Preparation method of high-strength PTFE dustproof and waterproof sound transmission membrane

Abstract

The invention discloses a preparation method of a high-strength PTFE dustproof and waterproof sound transmission membrane. The preparation method comprises the following steps: S1, uniformly mixing polytetrafluoroethylene dispersion resin and auxiliary oil to obtain a mixture; s2, sequentially compacting and extruding the mixture to obtain a columnar blank, and calendering the columnar blank to obtain a polytetrafluoroethylene base band; s3, carrying out drying and degreasing treatment on the polytetrafluoroethylene base band; s4, longitudinally stretching the polytetrafluoroethylene base band subjected to the drying and degreasing treatment to obtain a first material band; s5, performing high-temperature sintering on the first material belt to obtain a second material belt; s6, the second material strip is rapidly cooled to 2-7 DEG C, and a third material strip is obtained; and S7, the third material belt is transversely stretched. By means of the mode, according to the preparation method of the high-strength PTFE dustproof and waterproof sound transmission membrane, the obtained membrane product is high in strength, can be directly used without additional supporting materials and can have the high air permeability, and therefore the air pressure balance inside and outside equipment and the good sound transmission performance are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of sound-permeable membranes, and in particular to a method for preparing a high-strength PTFE dust-proof and waterproof sound-permeable membrane. Background Art

[0002] Dustproof and waterproof sound-permeable membrane can maintain the sound quality after the sound passes through, and block the passage of foreign objects such as liquids and dust. With the development of science and technology, the proportion of smart devices in our lives is getting higher and higher. Since it is the main component of electronic components, certain protective measures are indispensable. Dustproof and waterproof sound-permeable membrane is widely used in mobile speakers, walkie-talkies, mobile computers, Bluetooth, headphones, hearing aids, radios and other electronic products.

[0003] When dustproof, waterproof and sound-permeable membranes are used on various devices, they must not only be dustproof and waterproof, but also have to consider air permeability and balance the air pressure inside and outside the equipment. At the same time, it is necessary to try to ensure that the sound quality does not change much after the sound passes through the sound-permeable membrane.

[0004] Most sound-permeable membranes are made of multiple layers, such as a membrane + mesh waterproof layer. The mesh is placed behind the membrane and can provide good support. This structure can prevent the pressure difference between the inside and outside of the sound-permeable membrane from being too large, that is, when the pressure inside and outside the equipment is not balanced in time, excessive deformation will damage the sound-permeable membrane, thereby affecting the sound transmission effect; this structure can also improve the waterproof and dustproof effect of the membrane. For example, the composite membrane waterproofing is achieved by combining non-woven fabric and membrane by hot pressing to achieve support and waterproof and dustproof effects.

[0005] In the above-mentioned prior art, the waterproof sound-permeable membrane requires an additional supporting structure to ensure its strength. Whether using dispensing or thermal lamination, increasing the number and thickness of the sound-permeable membrane will affect the sound-permeable effect of the film, resulting in excessive loss of sound quality and increased use costs. Due to the limitation of the supporting material, the overall temperature resistance of the waterproof sound-permeable membrane will also decrease. Summary of the invention

[0006] The main technical problem solved by the present invention is to provide a method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane. The obtained membrane product has high strength and can be used directly without additional supporting materials. It also has a high air permeability, thereby ensuring the air pressure balance inside and outside the equipment and good sound permeability.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane, comprising the following steps: S1, uniformly mixing polytetrafluoroethylene dispersion resin and auxiliary oil to obtain a mixture; S2, compacting and extruding the mixture in sequence to obtain a columnar blank, and rolling the columnar blank to obtain a polytetrafluoroethylene tape; S3, drying and degreasing the polytetrafluoroethylene tape; S4, longitudinally stretching the dried and degreased polytetrafluoroethylene tape to obtain a first tape; S5, sintering the first material strip at high temperature to obtain a second material strip; S6, rapidly cooling the second material strip to 2-7° C. to obtain a third material strip; S7. Transversely stretch the third material strip to obtain a high-strength PTFE dust-proof, waterproof and sound-permeable membrane.

[0008] In a preferred embodiment of the present invention, the S1 is selected from 1 part by weight of polytetrafluoroethylene dispersion resin and 0.22-0.34 parts by weight of auxiliary oil mixed in proportion.

[0009] In a preferred embodiment of the present invention, the step S4 is performed at a temperature of 200-350°C.

[0010] In a preferred embodiment of the present invention, the step S5 is performed at a temperature of 345-385° C., and the sintering time is 0.8-4 min.

[0011] In a preferred embodiment of the present invention, the cooling time of the S6 rapid cooling treatment is controlled within 1-5 minutes, and the temperature drop rate of the third material strip is controlled within 14-22°C / s.

[0012] In a preferred embodiment of the present invention, the step S7 is performed at a temperature of 200-400°C.

[0013] The beneficial effects of the present invention are: the present invention provides a method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane, the obtained membrane product has high strength, can be used directly without additional supporting materials, and can have a high air permeability, thereby ensuring the air pressure balance inside and outside the equipment and good sound permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 It is the test result of the material obtained by the method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane in the X direction; Figure 2 and Figure 3 It is the test data of dustproof, waterproof and sound-permeable membranes of different standards; Figure 4It is the test data of film strength. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] like Figure 1-4 As shown, the embodiment of the present invention includes: A method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane comprises the following steps: S1, uniformly mixing polytetrafluoroethylene dispersion resin and auxiliary oil to obtain a mixture; S2, compacting and extruding the mixture in sequence to obtain a columnar blank, and rolling the columnar blank to obtain a polytetrafluoroethylene tape; S3, drying and degreasing the polytetrafluoroethylene tape; S4, longitudinally stretching the dried and degreased polytetrafluoroethylene tape to obtain a first tape; S5, sintering the first material strip at high temperature to obtain a second material strip; S6, rapidly cooling the second material strip to 2-7° C. to obtain a third material strip; S7. Transversely stretch the third material strip to obtain a high-strength PTFE dust-proof, waterproof and sound-permeable membrane.

[0017] The S1 is prepared by mixing 1 part by weight of polytetrafluoroethylene dispersion resin and 0.22-0.34 parts by weight of auxiliary oil in a certain proportion.

[0018] Furthermore, the step S4 is performed at a temperature of 200-350°C.

[0019] Furthermore, the step S5 is carried out at a temperature of 345-385° C., and the sintering time is 0.8-4 min.

[0020] Furthermore, the cooling time of the S6 rapid cooling treatment is controlled within 1-5 minutes, and the temperature drop rate of the third material strip is controlled within 14-22°C / s.

[0021] Furthermore, the step S7 is performed at a temperature of 200-400°C.

[0022] The thickened waterproof and sound-permeable membrane prepared by the above method does not require additional material support and has good fastness and toughness. On the premise of ensuring the waterproof, breathable and sound-permeable quality, it can not only reduce the production process and production cost of the waterproof and sound-permeable membrane but also ensure its own strength.

[0023] The approximate data of the waterproof and sound-permeable membrane prepared according to the above method are as follows: Thickness 25-55 , initial bubble pressure 0.006-0.011 , flow ≥ 196 / / , flow rate ≤1.1 、Aperture 7 Figure 1 The acoustic test results in the X direction for this product show that the FR value in the middle part is within the Limit range within the frequency range of 100-10kHz, and the edge area only slightly exceeds the Limit Down range at 8.5k-10kHz.

[0024] Combined with Figure 2 and Figure 3 It can be seen that if the FR value is to be guaranteed to be between Limit UP and Limit down, the dustproof, waterproof and sound-permeable membranes of samples No. 1, No. 2 and No. 3 fully meet the requirements.

[0025] Depend on Figure 4 It can be found that the strength of this product is much higher than that of traditional sound-transmitting membranes in both the X (horizontal) and Y (vertical) directions, ensuring that this dust-proof and waterproof sound-transmitting membrane can be directly used on a fixing fixture without the need for additional supporting materials.

[0026] In summary, the present invention provides a method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane. The resulting membrane product has high strength and can be used directly without additional supporting materials. It also has a high air permeability, thereby ensuring the air pressure balance inside and outside the equipment and good sound permeability.

[0027] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane, characterized in that: The following steps are involved: S1, uniformly mixing polytetrafluoroethylene dispersion resin and auxiliary oil to obtain a mixture; S2, compacting and extruding the mixture in sequence to obtain a columnar blank, and rolling the columnar blank to obtain a polytetrafluoroethylene tape; S3, drying and degreasing the polytetrafluoroethylene tape; S4, longitudinally stretching the dried and degreased polytetrafluoroethylene tape to obtain a first tape; S5, sintering the first material strip at high temperature to obtain a second material strip; S6, rapidly cooling the second material strip to 2-7° C. to obtain a third material strip; S7. Transversely stretch the third material strip to obtain a high-strength PTFE dust-proof, waterproof and sound-permeable membrane.

2. The method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane according to claim 1, characterized in that: The S1 is prepared by mixing 1 part by weight of polytetrafluoroethylene dispersion resin and 0.22-0.34 parts by weight of auxiliary oil in a certain proportion.

3. The method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane according to claim 1, characterized in that: The step S4 is performed at a temperature of 200-350°C.

4. The method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane according to claim 1, characterized in that: The step S5 is carried out at a temperature of 345-385° C., and the sintering time is 0.8-4 min.

5. The method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane according to claim 1, characterized in that: The cooling time of the S6 rapid cooling treatment is controlled within 1-5 minutes, and the temperature drop rate of the third material strip is controlled within 14-22°C / s.

6. The method for preparing a high-strength PTFE dustproof, waterproof and sound-permeable membrane according to claim 1, characterized in that: The step S7 is performed at a temperature of 200-400°C.

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