Extrusion die, polytetrafluoroethylene film and preparation method and application thereof

Abstract

The invention belongs to the technical field of microporous membrane preparation, and particularly relates to an extrusion die, a polytetrafluoroethylene film and a preparation method and application of the polytetrafluoroethylene film. The extrusion die comprises a first shell and a second shell which are communicated with each other, the first shell is provided with at least one cavity, and at least two different roughness degrees are arranged on the surface, making contact with materials, of the cavity. The polytetrafluoroethylene film prepared by the extrusion die has the advantages of high strength, high filtering efficiency, good air permeability and the like, and the preparation of the polytetrafluoroethylene film can be completed without adopting a complex process.

Description

technical field

[0001] The invention belongs to the technical field of microporous membrane preparation, and in particular relates to an extrusion die, a polytetrafluoroethylene film and a preparation method and application thereof. Background technique

[0002] Polytetrafluoroethylene expanded microporous membrane (PTFE) is widely used in the filtration industry due to its excellent chemical stability, temperature resistance and high porosity. However, because PTFE is a non-melt flow material, it cannot flow even when it reaches the decomposition temperature. It is difficult, and the existing technology generally adopts the process of extrusion and stretching to prepare PTFE membrane. Specifically, the existing preparation process of polytetrafluoroethylene microporous membrane is to mix polytetrafluoroethylene resin with oil agent, and then prepare The filler in the billet, after pressing, forms a compact billet with uniform density, which is pushed through a circular die,...

Examples

Embodiment 1

[0050] This embodiment provides an extrusion die, including a connected first shell 1 and a second shell 2,

[0051] Such as figure 1 As shown, the first housing 1 is provided with at least one cavity 1-1, and the cavity includes a material inlet 1-1-1 and a material outlet 1-1-2. After the material enters the first housing 1, it is extruded , discharged from the material outlet into the second housing 2, and at least two different roughnesses are set on the surface of the cavity in contact with the material. When the extrusion die is used to prepare polytetrafluoroethylene film, it can make the film have the advantages of strength, high filtration efficiency, and good air permeability. At the same time, the extrusion die has no special requirements for the processing technology of polytetrafluoroethylene film. There is no need to employ complicated processes.

[0052] Specifically, at least two different roughnesses are set on the surface of the cavity, and the roughness (R...

Embodiment 2

[0061] The present embodiment provides a kind of extruding mold of preparing polytetrafluoroethylene film, as Figure 3-5 shown, including,

[0062] The first housing is provided with a first cavity 1-1, a second cavity 1-2 and a third cavity 1-3, the first cavity, the second cavity and the third cavity are all of circular frustum structure, And the axis of the circular frustum structure is parallel to the horizontal plane; the inner surface a of the first cavity 1-1 is provided with a first area and a second area, the roughness of the first area is 50, the roughness of the second area is 0.025, and the first area It is surrounded by the first arc, the second arc, the first busbar and the second busbar, the second area is surrounded by the third arc, the fourth arc, the first busbar and the second busbar, and the first area The arc length is 1 / 2 of the circumference of the circle where it is located, that is, the frustum structure is divided into upper and lower parts along t...

Embodiment 3

[0066] The present embodiment provides a kind of extruding mold for preparing polytetrafluoroethylene film, with image 3 ,include,

[0067] The first housing is provided with a first cavity 1-1, a second cavity 1-2 and a third cavity 1-3, the first cavity, the second cavity and the third cavity are all of circular frustum structure, And the axis of the circular frustum structure is parallel to the horizontal plane; the inner surface a of the first cavity 1-1 is provided with a first area and a second area, the roughness of the first area is 50, the roughness of the second area is 0.1, and the first area It is surrounded by the first arc, the second arc, the first busbar and the second busbar, the second area is surrounded by the third arc, the fourth arc, the first busbar and the second busbar, and the first area The arc length is 1 / 2 of the circumference of the circle where it is located, that is, the frustum structure is divided into upper and lower parts along the horizon...

technical field

[0001] The invention belongs to the technical field of microporous membrane preparation, and in particular relates to an extrusion die, a polytetrafluoroethylene film and a preparation method and application thereof. Background technique

[0002] Polytetrafluoroethylene expanded microporous membrane (PTFE) is widely used in the filtration industry due to its excellent chemical stability, temperature resistance and high porosity. However, because PTFE is a non-melt flow material, it cannot flow even when it reaches the decomposition temperature. It is difficult, and the existing technology generally adopts the process of extrusion and stretching to prepare PTFE membrane. Specifically, the existing preparation process of polytetrafluoroethylene microporous membrane is to mix polytetrafluoroethylene resin with oil agent, and then prepare The filler in the billet, after pressing, forms a compact billet with uniform density, which is pushed through a circular die,...

Examples

Embodiment 1

[0050] This embodiment provides an extrusion die, including a connected first shell 1 and a second shell 2,

[0051] Such as figure 1 As shown, the first housing 1 is provided with at least one cavity 1-1, and the cavity includes a material inlet 1-1-1 and a material outlet 1-1-2. After the material enters the first housing 1, it is extruded , discharged from the material outlet into the second housing 2, and at least two different roughnesses are set on the surface of the cavity in contact with the material. When the extrusion die is used to prepare polytetrafluoroethylene film, it can make the film have the advantages of strength, high filtration efficiency, and good air permeability. At the same time, the extrusion die has no special requirements for the processing technology of polytetrafluoroethylene film. There is no need to employ complicated processes.

[0052] Specifically, at least two different roughnesses are set on the surface of the cavity, and the roughness (R...

Embodiment 2

[0061] The present embodiment provides a kind of extruding mold of preparing polytetrafluoroethylene film, as Figure 3-5 shown, including,

[0062] The first housing is provided with a first cavity 1-1, a second cavity 1-2 and a third cavity 1-3, the first cavity, the second cavity and the third cavity are all of circular frustum structure, And the axis of the circular frustum structure is parallel to the horizontal plane; the inner surface a of the first cavity 1-1 is provided with a first area and a second area, the roughness of the first area is 50, the roughness of the second area is 0.025, and the first area It is surrounded by the first arc, the second arc, the first busbar and the second busbar, the second area is surrounded by the third arc, the fourth arc, the first busbar and the second busbar, and the first area The arc length is 1 / 2 of the circumference of the circle where it is located, that is, the frustum structure is divided into upper and lower parts along t...

Embodiment 3

[0066] The present embodiment provides a kind of extruding mold for preparing polytetrafluoroethylene film, with image 3 ,include,

[0067] The first housing is provided with a first cavity 1-1, a second cavity 1-2 and a third cavity 1-3, the first cavity, the second cavity and the third cavity are all of circular frustum structure, And the axis of the circular frustum structure is parallel to the horizontal plane; the inner surface a of the first cavity 1-1 is provided with a first area and a second area, the roughness of the first area is 50, the roughness of the second area is 0.1, and the first area It is surrounded by the first arc, the second arc, the first busbar and the second busbar, the second area is surrounded by the third arc, the fourth arc, the first busbar and the second busbar, and the first area The arc length is 1 / 2 of the circumference of the circle where it is located, that is, the frustum structure is divided into upper and lower parts along the horizon...

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