Fuel gas leakage detection color-changing flexible film based on lead acetate dual-mode response as well as preparation method and application of fuel gas leakage detection color-changing flexible film

Abstract

The invention belongs to the technical field of gas sensing materials and safety monitoring, and discloses a gas leakage detection color-changing flexible film based on lead acetate dual-mode response and a preparation method and application thereof, and the method comprises the following steps: coating a molecular sieve layer: mixing ZSM-5 zeolite powder with polyvinyl alcohol, and blade-coating a PET substrate; catalytic layer loading: ball-milling and mixing lead acetate, Pd nanoparticles and mesoporous SiO2, and coating the molecular sieve layer with the mixture to obtain a Pd-lead acetate catalytic layer; performing reaction layer and packaging: performing pure lead acetate slurry coating to obtain a reaction layer, and performing vapor deposition on a PI layer to obtain a packaging layer; gum treatment: spraying high-temperature-resistant silica gel, and curing to form a self-adhesive layer; the mass ratio of the molecular sieve layer to the Pd-lead acetate catalyst layer to the reaction layer to the encapsulation layer is (20-30): (50-60): (10-15): (5-10). The product provided by the invention has relatively good flexible adaptability and environmental robustness; and quick response and low-cost mass production can be realized.

Description

Technical Field

[0001] This invention belongs to the field of gas sensing materials and safety monitoring technology, specifically relating to a flexible dual-mode gas leak detection film based on lead acetate composite material. It can simultaneously detect methane (CH4) and hydrogen sulfide (H2S) through color changes and is designed with a wound structure, suitable for leak location and real-time early warning at the connection of urban gas pipeline networks and liquefied petroleum gas (LPG) pipelines. Background Technology

[0002] The description of the background art in this invention pertains to related technologies and is used merely for illustration and to facilitate understanding of the invention. It should not be construed as the applicant explicitly believing or presuming that the invention was prior art on the filing date of the first application.

[0003] Traditional gas sensors (such as electrochemical and infrared sensors) require external power, making them unsuitable for passive applications and unable to directly locate leaks. Lead-based color-changing films (such as CN 112444514A) are difficult to promote due to toxicity issues and lack flexible design, making them unsuitable for conforming to curved pipe surfaces. Single-gas detection films (such as WO3 and MOFs) cannot meet the multi-component detection requirements of sulfur-containing town gas.

[0004] There is a lack of a flexible, non-toxic, encapsulated gas leak detection material with dual-mode color differentiation, especially suitable for the complex working conditions at pipe connections. Summary of the Invention

[0005] The purpose of this invention is to provide a color-changing flexible film for gas leak detection based on a dual-mode response of lead acetate, its preparation method, and its application. The product of this invention has good flexibility and environmental robustness; and can achieve rapid response and low-cost mass production.

[0006] The objective of this invention is achieved through the following technical solutions:

[0007] A method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response includes the following steps:

[0008] Molecular sieve coating: ZSM-5 zeolite powder is mixed with polyvinyl alcohol and coated onto a PET substrate;

[0009] Catalyst layer loading: Lead acetate, Pd nanoparticles, and mesoporous SiO2 are ball-milled and mixed, and then coated onto a molecular sieve layer to obtain a Pd-lead acetate catalyst layer;

[0010] Reaction layer and encapsulation: The reaction layer is obtained by coating with pure lead acetate paste, and the encapsulation layer is obtained by vapor deposition of PI layer;

[0011] Backing treatment: High-temperature resistant silicone is sprayed on, and a self-adhesive layer is formed after curing;

[0012] The mass ratio of the molecular sieve layer, the Pd-lead acetate catalyst layer, the reaction layer, and the encapsulation layer is 20-30: 50-60: 10-15: 5-10.

[0013] Furthermore, in the molecular sieve layer coating, the particle size of ZSM-5 zeolite powder is 1 μm, the concentration of polyvinyl alcohol is 5 wt%, the thickness of the PET substrate is 10-20 μm, and the thickness of the molecular sieve layer is 10-30 μm.

[0014] Furthermore, the catalyst layer loading, by mass percentage, includes the following components: lead acetate: 50%; Pd nanoparticles: 5%; mesoporous SiO2: 30%; Pd-lead acetate catalyst layer thickness: 40 μm;

[0015] The Pd nanoparticles have a loading of 3-6 wt%, a particle size of 2-5 nm, and are surface-modified with 1-3 wt% Fe3O4 sulfur scavenger.

[0016] Furthermore, the thickness of the pure lead acetate paste coating is 15 μm; the thickness of the vapor-deposited PI layer is 0.8 μm.

[0017] Furthermore, the high-temperature resistant silicone is resistant to 150℃; the peel strength of the self-adhesive layer is 1.8 N / cm.

[0018] A flexible color-changing film for gas leak detection based on a lead acetate dual-mode response is prepared by the method described above. The flexible color-changing film for gas leak detection based on a lead acetate dual-mode response comprises, from bottom to top, a flexible PET substrate, a ZSM-5 molecular sieve layer, a Pd-lead acetate catalyst layer, a pure lead acetate reaction layer, and a polyimide encapsulation layer; a high-temperature resistant silicone layer is coated on the back of the flexible PET substrate.

[0019] Furthermore, the total thickness is ≤100μm, the elongation at break is >150%, the minimum bending radius is ≤3mm; after 1000 cyclic bending cycles, the membrane shows no cracking, and the response time deviation is <5%.

[0020] Furthermore, the lead permeation of the PI encapsulation layer is <0.05 μg / cm³. 2 / day.

[0021] An application of a color-changing flexible film for gas leak detection based on a dual-mode response of lead acetate in gas leak detection: the film is wrapped around pipe elbows and flanges with a bonding gap of <0.1mm; the detection limit for CH4 is 0.1% with a response time of ≤30 seconds; the detection limit for H2S is 5ppm with a response time of ≤10 seconds; the performance degradation is <5% at 90% humidity and temperatures ranging from -20℃ to 120℃; and the film has UV resistance of >1000 hours.

[0022] The embodiments of the present invention have the following beneficial effects:

[0023] A dual-color (yellow / black) spatial detection method is achieved through ZSM-5 molecular sieve filtration, Pd-catalyzed exothermic methane oxidation, and direct H2S reaction. This membrane combines high sensitivity (CH4 0.1%, H2S 5ppm), flexible winding characteristics (bending radius ≤3mm), and industrial-grade safety (lead permeability <0.05μg / cm³). 2 / day), applicable to leak location and real-time early warning of urban gas pipeline networks and LNG storage and transportation facilities.

[0024] The product of this invention can be wound around complex parts such as DN20-DN200 pipe elbows and flanges, with a bonding gap of <0.1mm. The detection limit for CH4 is 0.1% (response time ≤30 seconds), and the detection limit for H2S is 5ppm (response time ≤10 seconds). Environmental robustness: performance degradation is <5% at 90% humidity and temperatures ranging from -20℃ to 120℃; UV resistance is >1000 hours. The roll-to-roll coating process has a production efficiency >10m³ / h. 2 / min, overall cost <600 yuan / m 2 . Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the flexible thin film structure in this invention;

[0026] Figure 2 This is a diagram illustrating an application scenario of the flexible membrane wrapping method in this invention (attached at a pipe flange).

[0027] Figure 3 This is a dynamic diagram of the dual-mode color-changing mechanism in this invention (CH4→yellow, H2S→black);

[0028] Figure 4 This is a curve showing the relationship between lead permeability and PI encapsulation layer thickness in this invention. Detailed Implementation

[0029] The present application will be further described below with reference to the embodiments.

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, in the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Different embodiments can be substituted or combined, and for those skilled in the art, other implementation methods can be obtained based on these embodiments without creative effort.

[0031] A method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response includes the following steps:

[0032] Molecular sieve coating: ZSM-5 zeolite powder is mixed with polyvinyl alcohol and coated onto a PET substrate;

[0033] Catalyst layer loading: Lead acetate, Pd nanoparticles, and mesoporous SiO2 are ball-milled and mixed, and then coated onto a molecular sieve layer to obtain a Pd-lead acetate catalyst layer;

[0034] Reaction layer and encapsulation: The reaction layer is obtained by coating with pure lead acetate paste, and the encapsulation layer is obtained by vapor deposition of PI layer;

[0035] Backing treatment: High-temperature resistant silicone is sprayed on, and a self-adhesive layer is formed after curing;

[0036] The mass ratio of the molecular sieve layer, the Pd-lead acetate catalyst layer, the reaction layer, and the encapsulation layer is 20-30: 50-60: 10-15: 5-10.

[0037] A schematic diagram of the flexible thin film structure is shown below. Figure 1 As shown.

[0038] The material composition is shown in the table below:

[0039]

[0040] Dual-mode color differentiation

[0041] CH4 leakage: Pd catalytic oxidation releases heat, and lead acetate decomposes into yellow PbO, with the color changing from white to bright yellow (ΔE≥35);

[0042] H2S leakage: Direct reaction produces black PbS precipitate, color changes from white to dark black (ΔE≥45);

[0043] Mixed leakage: Yellow and black mottled pattern, visible to the naked eye (ΔE difference > 15);

[0044] Toxicity control technology

[0045] Lead permeability of PI encapsulation layer <0.05μg / cm 2 / day (RoHS standard limit 1μg / cm) 2 / day);

[0046] Accompanying recycling agreement: Waste membranes are soaked in a 5% nitric acid solution, with a lead recovery rate of >95%.

[0047] In some embodiments of the present invention, in the molecular sieve layer coating, the particle size of ZSM-5 zeolite powder is 1 μm, the concentration of polyvinyl alcohol is 5 wt%, the thickness of the PET substrate is 10-20 μm, and the thickness of the molecular sieve layer is 10-30 μm.

[0048] In some embodiments of the present invention, the catalyst layer loading comprises, by mass percentage, the following components: lead acetate: 50%; Pd nanoparticles: 5%; mesoporous SiO2: 30%; and the Pd-lead acetate catalyst layer thickness is 40 μm.

[0049] The Pd nanoparticles have a loading of 3-6 wt%, a particle size of 2-5 nm, and are surface-modified with 1-3 wt% Fe3O4 sulfur scavenger.

[0050] In some embodiments of the present invention, the thickness of the pure lead acetate paste coating is 15 μm; the thickness of the vapor-deposited PI layer is 0.8 μm.

[0051] In some embodiments of the present invention, the high-temperature resistant silicone is resistant to 150°C; the peel strength of the self-adhesive layer is 1.8 N / cm.

[0052] A color-changing flexible film for gas leak detection based on a lead acetate dual-mode response is prepared by the method described above; Figure 1 As shown, the color-changing flexible film for gas leak detection based on lead acetate dual-mode response comprises, from bottom to top, a flexible PET substrate, a ZSM-5 molecular sieve layer, a Pd-lead acetate catalyst layer, a pure lead acetate reaction layer, and a polyimide encapsulation layer; the back of the flexible PET substrate is coated with a high-temperature resistant silicone layer.

[0053] In some embodiments of the present invention, the total thickness is ≤100μm, the elongation at break is >150%, the minimum bending radius is ≤3mm, the film does not crack after 1000 cyclic bending cycles, and the response time deviation is <5%.

[0054] In some embodiments of the present invention, the lead permeability of the PI encapsulation layer is <0.05 μg / cm³. 2 / day.

[0055] An application of a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response in gas leak detection, such as... Figure 2 As shown, the spiral wound pipe flange has a fitting gap of <0.1mm; CH4 detection limit of 0.1% and response time of ≤30 seconds; H2S detection limit of 5ppm and response time of ≤10 seconds; performance degradation of <5% at 90% humidity and -20℃ to 120℃; and UV resistance of >1000 hours.

[0056] Figure 3 This is a dynamic diagram of the dual-mode color-changing mechanism (CH4→yellow, H2S→black).

[0057] Frame 1: Gas adsorption [ZSM-5 channels] → CH4 (circular) enters the Pd-lead acetate catalyst layer

[0058] H2S (triangular) enters the lead acetate reaction layer.

[0059] Frame 2: CH4 Catalytic Oxidation

[0060] CH4 is exothermic under the catalysis of a Pd catalyst (black circular shape).

[0061] Lead acetate (white) → heat → PbO (yellow) ΔE = 35

[0062] Frame 3: Direct H2S reaction

[0063] Lead acetate (white) + H₂S → PbS (black) ΔE = 45

[0064] Frame 4: Mixed Leaks

[0065] Yellow (CH4) + Black (H2S) → Yellow and black mottled pattern.

[0066] Figure 4 This is a curve showing the relationship between lead permeability and PI encapsulation layer thickness in this invention.

[0067] The embodiments of the present invention have the following beneficial effects:

[0068] A dual-color (yellow / black) spatial detection method is achieved through ZSM-5 molecular sieve filtration, Pd-catalyzed exothermic methane oxidation, and direct H2S reaction. This membrane combines high sensitivity (CH4 0.1%, H2S 5ppm), flexible winding characteristics (bending radius ≤3mm), and industrial-grade safety (lead permeability <0.05μg / cm³). 2 / day), applicable to leak location and real-time early warning of urban gas pipeline networks and LNG storage and transportation facilities.

[0069] The product of this invention can be wound around complex parts such as DN20-DN200 pipe elbows and flanges, with a bonding gap of <0.1mm. The detection limit for CH4 is 0.1% (response time ≤30 seconds), and the detection limit for H2S is 5ppm (response time ≤10 seconds). Environmental robustness: performance degradation is <5% at 90% humidity and temperatures ranging from -20℃ to 120℃; UV resistance is >1000 hours. The roll-to-roll coating process has a production efficiency >10m³ / h. 2 / min, overall cost <600 yuan / m 2 .

[0070] Example 1: Flexible Membrane Preparation

[0071] 1. Molecular sieve layer coating:

[0072] ZSM-5 zeolite powder (particle size 1 μm) was mixed with polyvinyl alcohol (PVA, 5 wt%) and coated onto a PET substrate (thickness 15 μm).

[0073] 2. Catalyst layer loading:

[0074] Lead acetate (50%), Pd nanoparticles (5%), and mesoporous SiO2 (30%) were ball-milled and mixed, and then coated onto a molecular sieve layer (40 μm thick).

[0075] 3. Reaction layer and encapsulation:

[0076] Pure lead acetate paste coating (15 μm thick), followed by vapor deposition of a PI layer (0.8 μm thick).

[0077] 4. Adhesive backing treatment

[0078] Spray with high-temperature resistant silicone (temperature resistance 150℃), which cures to form a self-adhesive layer (peel strength 1.8N / cm).

[0079] Example 2: Detection Performance

[0080] Flexibility test:

[0081] With a bending radius of 3mm, after 1000 cyclic bending cycles, the membrane showed no cracking, and the response time deviation was <5%.

[0082] Dual gas detection:

[0083]

[0084]

[0085] Industrial scenario simulation:

[0086] Wrapped around the flange of a DN50 pipe, simulating a 0.2% CH4 leak, a yellow ring appears around the leak point within 25 seconds, with a positioning error of <1cm.

[0087] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response, characterized in that, Includes the following steps: Molecular sieve coating: ZSM-5 zeolite powder is mixed with polyvinyl alcohol and coated onto a PET substrate; Catalyst layer loading: Lead acetate, Pd nanoparticles, and mesoporous SiO2 are ball-milled and mixed, and then coated onto a molecular sieve layer to obtain a Pd-lead acetate catalyst layer; Reaction layer and encapsulation: The reaction layer is obtained by coating with pure lead acetate paste, and the encapsulation layer is obtained by vapor deposition of PI layer; Backing treatment: High-temperature resistant silicone is sprayed on, and a self-adhesive layer is formed after curing; The mass ratio of the molecular sieve layer, the Pd-lead acetate catalyst layer, the reaction layer, and the encapsulation layer is 20-30: 50-60: 10-15: 5-10.

2. The method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response according to claim 1, characterized in that, In the aforementioned molecular sieve coating, the particle size of ZSM-5 zeolite powder is 1 μm, the concentration of polyvinyl alcohol is 5 wt%, the thickness of the PET substrate is 10-20 μm, and the thickness of the molecular sieve layer is 10-30 μm.

3. The method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response according to claim 1, characterized in that, The catalyst layer loading, by mass percentage, includes the following components: lead acetate: 50%; Pd nanoparticles: 5%; mesoporous SiO2: 30%; Pd-lead acetate catalyst layer thickness: 40 μm; The Pd nanoparticles have a loading of 3-6 wt%, a particle size of 2-5 nm, and are surface-modified with 1-3 wt% Fe3O4 sulfur scavenger.

4. The method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response according to claim 1, characterized in that, The thickness of the pure lead acetate paste coating is 15 μm; the thickness of the vapor-deposited PI layer is 0.8 μm.

5. The method for preparing a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response according to claim 1, characterized in that, The high-temperature resistant silicone is resistant to 150℃; the peel strength of the self-adhesive layer is 1.8 N / cm.

6. A color-changing flexible film for gas leak detection based on a lead acetate dual-mode response, characterized in that, The color-changing flexible gas leak detection film based on lead acetate dual-mode response is prepared by the method described in any one of claims 1-5; the color-changing flexible gas leak detection film based on lead acetate dual-mode response comprises, from bottom to top, a flexible PET substrate, a ZSM-5 molecular sieve layer, a Pd-lead acetate catalyst layer, a pure lead acetate reaction layer, and a polyimide encapsulation layer; the back of the flexible PET substrate is coated with a high-temperature resistant silicone layer.

7. The color-changing flexible film for gas leak detection based on a lead acetate dual-mode response according to claim 6, characterized in that, Total thickness ≤100μm, elongation at break >150%, minimum bending radius ≤3mm; after 1000 cycles of bending, the membrane shows no cracking, and the response time deviation is <5%.

8. The color-changing flexible film for gas leak detection based on a dual-mode lead acetate response according to claim 6, characterized in that, Lead permeability of PI encapsulation layer <0.05μg / cm 2 / day.

9. An application of a color-changing flexible film for gas leak detection based on a lead acetate dual-mode response in gas leak detection, characterized in that, For spiral wound pipe elbows and flanges, the fitting gap is <0.1mm; CH4 detection limit is 0.1%, and the response time is ≤30 seconds; H2S detection limit is 5ppm, and the response time is ≤10 seconds; performance degradation is <5% at 90% humidity and -20℃ to 120℃, and UV resistance is >1000 hours.

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