Production method of ultrathin polyamide film

Abstract

The invention discloses a production method of an ultrathin polyamide film. The polyamide film is composed of PA6, PA612, lithium chloride, hectorite and modified nano-zinc oxide. And the thickness of the polyamide film is 9 microns. Lithium chloride is added, so that the melting point of the composite material is reduced, large-scale continuous production is facilitated, but the mechanical properties of PA6 and PA612 become poor due to lithium chloride, so that the tensile strength and bending strength of the composite material are improved by adding hectorite, and the composite material has better mechanical properties and plays a role in enhancement; the modified nano-zinc oxide can be used as a nucleating agent to promote crystallization of PA6 and PA612, the modified nano-zinc oxide has small influence on the thermal stability of PA6 and PA612, and the modified nano-zinc oxide also has an antibacterial effect; after the film is subjected to radiation modification, the mechanical property and modulus of the composite material can be remarkably improved.

Description

Technical Field

[0001] The invention relates to a method for producing an ultra-thin polyamide film. Background Art

[0002] BOPA is a biaxially oriented nylon film, which is an important material for producing various composite packaging materials. The existing BOPA film usually has a three-layer structure, namely: upper surface layer, core layer and lower surface layer. Ordinary PA film has the following disadvantages: PA has a high melting point and is not suitable for large-scale continuous production; PA antibacterial packaging materials are increasingly valued, and inorganic antibacterial agents can be used for antibacterial, but they have the disadvantages of low crystallinity and poor thermal stability. Summary of the invention

[0003] In view of the above-mentioned defects of the prior art, an object of the present invention is to provide a method for producing an ultra-thin polyamide film.

[0004] To solve the above problems, the technical solution of the present invention is: a method for producing an ultra-thin polyamide film, wherein the polyamide film is composed of PA6, PA612, lithium chloride, hectorite, and modified nano zinc oxide; the production method comprises the following steps: (1) preparing raw materials, wherein the modified nano zinc oxide is prepared by surface modification of nano zinc oxide using a coupling agent KH500; (2) Blending the raw materials and sending them into the extruder for mixing and plasticizing; (3) The molten melt is fed into the die, and the melt passes through the flat die orifice to form a molten sheet; (4) Using an air knife to attach the sheet to a chilled roller to quench it into an unshaped sheet, and then cooling it in a water bath to shape the sheet into a cast sheet; (5) The cast sheet is stretched to form a film; (6) Radiation modification of thin films; (7) Detect the film thickness; (8) Rewind the inspected film.

[0005] Furthermore, the components of the polyamide film are as follows by mass ratio: PA6 46%, PA612 49%, lithium chloride 1.5%, laponite 2.5%, and modified nano zinc oxide 1%.

[0006] Furthermore, step (6) is specifically as follows: the film is packaged in a PE plastic bag and placed in a Co-60 radiation source radiation room, where it is irradiated with a dose of 120 at a radiation dose rate of 10 kGy / h and room temperature.

[0007] Furthermore, step (7) includes the following steps: (71) Prepare a thickness gauge, wherein a rotatable circular turntable is installed at the lower end of the thickness gauge, a plurality of measuring platforms are distributed in a circle on the top of the turntable, and a measuring head is provided at the upper end of the thickness gauge that can move up and down; (72) Cut out a number of film blocks equal to the number of measuring platforms, and place one film block on each measuring platform; (73) The measuring head moves downward to measure the thickness of one of the film blocks. After the measurement, the turntable rotates one station and the measuring head measures the thickness of the second film block. All film blocks are measured in this way.

[0008] Furthermore, the thickness of the polyamide film is 9 micrometers.

[0009] The beneficial effects of the present invention are as follows: the addition of lithium chloride reduces the melting point of the composite material, which is conducive to large-scale continuous production; however, since lithium chloride deteriorates the mechanical properties of PA6 and PA612, the addition of hectorite improves the tensile strength and bending strength of the composite material, so that the composite material has better mechanical properties and plays a reinforcing role; the modified nano zinc oxide can be used as a nucleating agent to promote the crystallization of PA6 and PA612, and the modified nano zinc oxide has little effect on the thermal stability of PA6 and PA612, and the modified nano zinc oxide also plays an antibacterial role; after the film is subjected to radiation modification, the mechanical properties and modulus of the composite material can be significantly improved. Implementation

[0010] In order to more intuitively and completely understand the technical solution of the present invention, a non-limiting feature description is now provided as follows: The production method of ultra-thin polyamide film comprises PA6, PA612, lithium chloride, laponite and modified nano zinc oxide; the production method comprises the following steps: (1) preparing raw materials, wherein the modified nano zinc oxide is prepared by surface modification of nano zinc oxide using a coupling agent KH500; (2) Blending the raw materials and sending them into the extruder for mixing and plasticizing; (3) The molten melt is fed into the die, and the melt passes through the flat die orifice to form a molten sheet; (4) Using an air knife to attach the sheet to a chilled roller to quench it into an unshaped sheet, and then cooling it in a water bath to shape the sheet into a cast sheet; (5) The cast sheet is stretched to form a film; (6) Radiation modification of thin films; (7) Detect the film thickness; (8) Rewind the inspected film.

[0011] The components of the polyamide film are as follows by mass ratio: PA6 46%, PA612 49%, lithium chloride 1.5%, laponite 2.5%, and modified nano zinc oxide 1%.

[0012] Step (6) is as follows: the film is packaged in a PE plastic bag and placed in a Co-60 radiation source radiation room, where it is irradiated with a dose of 120 at a radiation dose rate of 10 kGy / h and room temperature.

[0013] Step (7) includes the following steps: (71) Prepare a thickness gauge, wherein a rotatable circular turntable is installed at the lower end of the thickness gauge, a plurality of measuring platforms are distributed in a circle on the top of the turntable, and a measuring head is provided at the upper end of the thickness gauge that can move up and down; (72) Cut out a number of film blocks equal to the number of measuring platforms, and place one film block on each measuring platform; (73) The measuring head moves downward to measure the thickness of one of the film blocks. After the measurement, the turntable rotates one station and the measuring head measures the thickness of the second film block. All film blocks are measured in this way.

[0014] By using the turntable in conjunction with the measuring head, there is no need to remove a piece of film after testing and then replace it with a new one for testing, which improves the testing efficiency.

[0015] The thickness of the polyamide film is 9 microns.

[0016] The addition of lithium chloride lowers the melting point of the composite material, which is conducive to large-scale continuous production. However, because lithium chloride deteriorates the mechanical properties of PA6 and PA612, the addition of hectorite improves the tensile strength and flexural strength of the composite material, giving the composite material better mechanical properties and playing a reinforcing role; modified nano zinc oxide can be used as a nucleating agent to promote the crystallization of PA6 and PA612, and the modified nano zinc oxide has little effect on the thermal stability of PA6 and PA612, and the modified nano zinc oxide also has an antibacterial effect; after the film is radiation modified, the mechanical properties and modulus of the composite material can be significantly improved.

Claims

1. A method for producing an ultra-thin polyamide film, characterized in that: The polyamide film is composed of PA6, PA612, lithium chloride, laponite, and modified nano zinc oxide; the production method comprises the following steps: (1) preparing raw materials, wherein the modified nano zinc oxide is prepared by surface modification of nano zinc oxide using a coupling agent KH500; (2) Blending the raw materials and sending them into the extruder for mixing and plasticizing; (3) The molten melt is fed into the die, and the melt passes through the flat die orifice to form a molten sheet; (4) Using an air knife to attach the sheet to a chilled roller to quench it into an unshaped sheet, and then cooling it in a water bath to shape the sheet into a cast sheet; (5) The cast sheet is stretched to form a film; (6) Radiation modification of thin films; (7) Detect the film thickness; (8) Rewind the inspected film.

2. The method for producing an ultra-thin polyamide film according to claim 1, characterized in that: The components of the polyamide film are as follows by mass ratio: PA6 46%, PA612 49%, lithium chloride 1.5%, laponite 2.5%, and modified nano zinc oxide 1%.

3. The method for producing an ultra-thin polyamide film according to claim 1, characterized in that: Step (6) is as follows: the film is packaged in a PE plastic bag and placed in a Co-60 radiation source radiation room, where it is irradiated with a dose of 120 at a radiation dose rate of 10 kGy / h and room temperature.

4. The method for producing an ultra-thin polyamide film according to claim 1, characterized in that: Step (7) includes the following steps: (71) Prepare a thickness gauge, wherein a rotatable circular turntable is installed at the lower end of the thickness gauge, a plurality of measuring platforms are distributed in a circle on the top of the turntable, and a measuring head is provided at the upper end of the thickness gauge that can move up and down; (72) Cut out a number of film blocks equal to the number of measuring platforms, and place one film block on each measuring platform; (73) The measuring head moves downward to measure the thickness of one of the film blocks. After the measurement, the turntable rotates one station and the measuring head measures the thickness of the second film block. All film blocks are measured in this way.

5. The method for producing an ultra-thin polyamide film according to claim 1, characterized in that: The thickness of the polyamide film is 9 microns.