High-strength high-transparency antibacterial composite isolation glue solution for cultural relic lining paper

Abstract

The invention relates to a high-strength and high-transparency antibacterial composite isolation glue solution for cultural relic lining paper. The glue solution takes a pore-foaming agent, an antibacterial agent and an isolation glue solution as main components, the pore-foaming agent is a compound system of nanoscale silicon dioxide, titanium dioxide and calcium carbonate, the antibacterial agent adopts a compound of berberine, epsilon-polylysine and nano-zinc oxide, and functional dispersion liquid is formed through synergistic modification of a silane coupling agent. A gradient-distributed microporous structure (porosity is greater than 40%) is constructed by utilizing a pore-foaming agent, and directional anchoring of an antibacterial agent in an adhesive layer is cooperated, so that the air permeability, the mechanical strength and the antibacterial and mildew-proof performance are synchronously improved, and the obtained cultural relic lining paper has a long-acting mildew-proof effect that the tensile strength is greater than 100N / cm, the water vapor transmission rate is 160ml / min and the aspergillus niger spore germination inhibition rate is 100%; the method is suitable for repairing and protecting fragile paper cultural relics such as paintings and calligraphies and ancient books.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-strength high-transparency antibacterial composite isolation glue for cultural relics backing paper and its preparation method, specifically relates to by silane coupling directional assembly technology constructs nano-pore forming agent / antibacterial agent composite dispersion system, utilize biomimetic gradient coating process to form the microporous structure (0.1-5 μm) of hierarchical distribution of pore size on paper base surface, simultaneously promote the air permeability and mechanical strength of backing paper, and realize the long-acting mildew-proof function of cultural relics based on the slow-release-photocatalytic synergistic antibacterial mechanism of plant source, belong to paper cultural relics protection material technical field. BACKGROUND

[0002] With the upgrading of global cultural heritage protection, the cross-century survival of paper cultural relics (such as calligraphy and painting, ancient books, archives) is facing severe challenges. As the last barrier to directly contact cultural relics, protective backing paper needs to simultaneously achieve three core functions in a dynamic environment: high air permeability (balance environmental humidity fluctuation, moisture permeability > 2500 g / m²·24h), high mechanical strength (tensile strength > 80 N / cm² to resist pick-and-place friction), and long-lasting antibacterial and mildew-proof (inhibit Aspergillus niger and other cultural relics corrosion bacteria, effective period > 20 years). The current mainstream technology uses a passive protection mode of "acid-free paper base + impregnated strengthening agent", which has fundamental defects: air permeability-strength mutual exclusion: impregnated acrylic resin increases the strength to 50-60 N / cm², but blocks the fiber pores, causing the moisture permeability to drop to < 100 ml / min, and the moisture retention increases the risk of cultural relics mildew by 300%; insufficient mildew-proof time: physical coating of quaternary ammonium salt antibacterial agent easily migrates and contaminates cultural relics, and the antibacterial rate decreases to < 40% within 3 years; poor chemical compatibility: sulfur-containing strengthening agent accelerates paper acidification, and the pH value decreases to 4.2-4.8 after 10 years of aging, far exceeding the safety threshold of cultural relics (pH > 6.5).

[0003] High-end cultural institutions are forced to rely on imported composite backing paper (such as Japanese paper), which achieves partial functions by coating isolation glue and antibacterial layers in multiple steps, but the multi-layer structure results in: thickness increase > 30 μm (base paper 35 μm + coating), loss of paper flexibility; isolation glue layer moisture permeability < 80 ml / min, frequent replacement of exhibit cabinet desiccant is required; cost as high as 2000 yuan / m², making it difficult to scale up. Therefore, it is urgent to develop a single-layer coating, performance-coordinated composite glue technology that simultaneously achieves gradient pore regulation, fiber strengthening anchoring, and intelligent mildew-proofing function in an ultra-thin coating (< 2 μm), completely solving the "triple contradiction" of cultural relics backing paper. SUMMARY

[0004] The technical purpose of the present application is to overcome the deficiencies of the prior art, to provide a high-strength high-transparency antibacterial cultural relics protection backing paper composite isolation glue with high strength, good air permeability and antibacterial performance.

[0005] To achieve the above object, the technical scheme adopted by the present application is: A preparation method of high-strength, high-transparency and antibacterial composite glue solution for cultural relic backing paper, comprising the following steps: Step 1, backing paper substrate pretreatment: select acid-free rice paper / silk paper (basis weight 35-45 g / m²) as the substrate, and perform plasma surface activation (power 100 W, time 3 s) to enhance the adhesion of the glue solution; Step 2, combined dispersion liquid preparation: mix nano-sized silicon dioxide, nano-sized titanium dioxide and nano-sized calcium carbonate in a certain proportion; add a plant source antibacterial compound and KH-550 silane coupling agent (total solid content 8%); and then perform gradient dispersion to obtain a stable dispersion liquid; Step 3, composite glue solution preparation: fuse the dispersion liquid and polyvinyl alcohol glue solution (solid content 22%) in a mass ratio of 1:4; add 0.3% sodium alginate to adjust the viscosity to 160±10 cP; Step 4, biomimetic gradient coating: use a micro-gravure coater (screen line number 180 lines / cm) to perform single-layer coating on the surface of the substrate; and accurately control the coating amount to be 0.8±0.1 g / m² (dry film thickness 1.2 μm); Step 5, two-stage gradient drying: pre-drying: 40°C hot air for 5 s (fixed surface layer 0.1-0.5 μm antibacterial micropores); main drying: 55°C pressure roller (0.3 MPa, 3 s) to form a middle layer 1-2 μm air-permeable channel and a bottom layer 3-5 μm fiber anchoring hole.

[0006] Preferably, the plasma treatment in step 1 makes the surface energy of the substrate >72 mN / m (unprocessed <40 mN / m), and the uniformity deviation of the glue solution spreading is <5%.

[0007] Preferably, the ratio of the pore-forming agents nano-sized silicon dioxide, nano-sized titanium dioxide and nano-sized calcium carbonate in step 2 is 4:1.5:3.

[0008] Preferably, in step 2, berberine and KH-550 silane coupling agent are reacted in ethanol at 60°C for 4 h, with a molar ratio of 1:0.3; and the modified product is ultrasonically compounded with nano-zinc oxide (300 W, 30 min).

[0009] Preferably, in step 2, the ratio of the antibacterial compound berberine (98%), ε-polylysine (food grade) and nano-zinc oxide (20 nm) is 45%:35%:20%.

[0010] Preferably, in step 2, the gradient dispersion is first premixed by low-speed ball milling (500 rpm, 2 h), and then high-pressure homogenization (800 bar, 0.5 h) is performed.

[0011] Preferably, in step 3, the polyvinyl alcohol glue solution has a polymerization degree of 1700±100, an alcoholysis degree of 88±2%, and a pH value of 7.3±0.2.

[0012] In step 4, the preferred dry film thickness is 1.2±0.2μm, light transmittance loss is <5%, porosity is 42±2%, and water vapor transmission rate is >160ml / min.

[0013] The preferred step 5 is cooling and shaping at 20°C with a cold roller at 0.1MPa for 2s to fix the bottom anchoring structure (reinforcing layer).

[0014] The beneficial effects of this invention are: This invention achieves a revolutionary breakthrough in the performance of cultural relic backing paper within a single layer of ultrathin adhesive solution (0.8–1.2 g / m²) through silane coupling directional assembly and biomimetic gradient coating technology. 1) Single-layer adhesive achieves gradient functional integration: Top layer: 0.1–0.5μm micropores physically block microorganisms (Aspergillus niger spore diameter 2–5μm), with a 100% antibacterial rate; Middle layer: 1–2μm through-holes achieve a moisture permeability of >160ml / min; Bottom layer: 3–5μm anchoring pores combined with nano-cellulose whiskers (CNC), with a tensile strength >100 N / cm². This simultaneously solves the traditional problem of mutual incompatibility between strength, breathability, and antibacterial properties in liner paper.

[0015] 2) Dual-mode intelligent anti-mold system: Slow-release layer: pH-responsive release of berberine (spore DNA replication inhibitor) and ε-polylysine (cell membrane dissolving agent), with an antibacterial rate of >99.9% in 28 days; Photocatalytic layer: Nano-titanium dioxide / zinc oxide generates active oxygen under visible light, accelerating the inactivation of hyphae; achieving century-level anti-mold protection for cultural relics and completely blocking the risk of mold growth in calligraphy, paintings and ancient books.

[0016] 3) Guarantee of absolute safety of cultural relics: Zero chemical migration: silane coupling agent covalently bonded antibacterial agent, the amount of precipitation after 50 years of accelerated aging is <0.1ppm; Neutral environment: polyvinyl alcohol adhesive pH=6.8-7.3; Optical compatibility: light transmittance >88% (550nm), avoiding the obscuring of cultural relic details during restoration. Detailed Implementation

[0017] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0018] A method for preparing a high-strength, high-permeability, antibacterial composite adhesive for use as backing paper for cultural relics includes the following steps: Step 1, Pretreatment of backing paper substrate: Select acid-free Xuan paper / mulberry bark paper (basis weight 35-45g / m²) as the substrate, and enhance the adhesion of the adhesive by plasma surface activation (power 100W, time 3s).

[0019] Step 2, combined dispersion preparation: mix nano-sized silicon dioxide, nano-sized titanium dioxide, nano-sized calcium carbonate in proportion; add plant-derived antibacterial complex and KH-550 silane coupling agent (total solid content 8%); then perform gradient dispersion to obtain stable dispersion.

[0020] Step 3, composite glue preparation: mix the dispersion with polyvinyl alcohol glue (solid content 22%) in a mass ratio of 1:4; add 0.3% sodium alginate to adjust the viscosity to 160±10 cP.

[0021] Step 4, biomimetic gradient coating: use a micro-gravure coater (mesh number 180 lines / cm) to coat a single layer on the surface of the substrate; the coating amount is accurately controlled to be 0.8±0.1 g / m² (dry film thickness 1.2 μm).

[0022] Step 5, two-stage gradient drying: pre-drying: 40°C hot air for 5s (fixed surface layer 0.1-0.5 μm antibacterial microporous); main drying: 55°C pressure roller (0.3 MPa, 3s) to form middle layer 1-2 μm air permeable channel and bottom layer 3-5 μm fiber anchoring hole.

[0023] Preferably, step 1 plasma treatment makes the surface energy of the substrate >72 mN / m (untreated <40 mN / m), and the uniformity deviation of glue spreading is <5%.

[0024] Preferably, step 2 porogen nano-sized silicon dioxide, nano-sized titanium dioxide, nano-sized calcium carbonate ratio is 4:1.5:3.

[0025] Preferably, step 2 berberine and KH-550 silane coupling agent react in ethanol at 60°C for 4h, molar ratio 1:0.3; the modified product is ultrasonically compounded with nano-zinc oxide (300W, 30min).

[0026] Preferably, step 2 antibacterial complex berberine (98%), ε-polylysine (food grade), nano-zinc oxide (20nm) ratio is 45%:35%:20%.

[0027] Preferably, step 2 gradient dispersion first low-speed ball milling (500 rpm, 2h) pre-mixing, then high-pressure homogenization (800 bar, 0.5h).

[0028] Preferably, step 3 composite glue preparation polyvinyl alcohol glue degree of polymerization 1700±100, alcoholysis degree 88±2%, pH=7.0±0.2.

[0029] Preferably, step 4 dry film thickness 1.2±0.2 μm light transmittance loss <5%; porosity 42±2% water vapor permeability >160 ml / min.

[0030] Preferred step 5 cooling and setting 20°C cold roll / 0.1 MPa / 2 s to fix the anchoring structure of the base layer (reinforcing layer) The application will be further described in detail below with reference to specific examples. Example

[0031] 1) Combined dispersion preparation: porogen: nano-sized silicon dioxide (50 nm) 4.0 g + nano-sized titanium dioxide (30 nm) 1.5 g + nano-sized calcium carbonate (80 nm, aspect ratio > 20) 3.0 g, antibacterial agent: modified berberine 1.8 g + ε-polylysine (food grade) 1.4 g + nano-zinc oxide (20 nm) 0.8 g, modifier: KH-550 silane coupling agent 0.9 g (total solid content 8%). Dispersion process: first ball milling dispersion (500 rpm, 2 h, zirconium oxide beads φ0.3 mm), then high-pressure homogenization (800 bar, 0.5 h), solid content 25%, room temperature standing for 12 h, sedimentation rate <0.1% 2) Composite glue fusion: mix the above dispersion with polyvinyl alcohol glue (polyvinyl alcohol, solid content 22%) according to the mass ratio 1:4, add 0.3% sodium alginate thickener, and adjust the viscosity to 160±10 cP.

[0032] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 40 g / m², pretreated with 100W plasma for 3s) coating process: micro-gravure transfer coating (screen line number 180 lines / cm, line speed 15 m / min) coating amount: 0.8±0.05 g / m² (dry film thickness 1.2 μm) gradient drying: pre-drying: 40°C hot air, air speed 8 m / s, time 5 s (lock the surface layer 0.1-0.5 μm microporous) main drying: 55°C pressure roller, pressure 0.3 MPa, time 3 s (form the middle layer 1-2 μm through-hole) 4) The high-strength, high-transparency, antibacterial composite isolation glue prepared in this embodiment for cultural relic backing paper has a water vapor permeability of 168 ml / min; a longitudinal tensile strength of 130.25 N / cm², a transverse tensile strength of 76.18 N / cm²; a longitudinal tear strength of 875.33 mN, a transverse tear strength of 982.45 mN; a bacteriostatic rate ≥99.95%, an antibacterial value ≥4.5. Example

[0033] 1) Combined dispersion liquid preparation: pore-forming agent: nano-sized silicon dioxide (50 nm) 4.5 g + nano-sized titanium dioxide (30 nm) 1.2 g + nano-sized calcium carbonate (80 nm, aspect ratio > 20) 2.8 g, antibacterial agent: modified berberine 1.6 g + ε-polylysine (food grade) 1.2 g + nano-zinc oxide (20 nm) 0.6 g, modifier: KH-550 silane coupling agent 0.8 g (total solid content 7.5%). Dispersion process: first ball milling dispersion (500 rpm, 2.0 h, zirconium oxide beads φ0.3 mm), then high pressure homogenization (800 bar, 0.8 h), solid content 24%, room temperature standing 12 h sedimentation rate <0.1% 2) Composite glue fusion: mix the above dispersion liquid with polyvinyl alcohol glue (polyvinyl alcohol, solid content 22%) according to the mass ratio 1:4.2, add 0.3% sodium alginate thickener, adjust the viscosity to 155±5 cP.

[0034] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 45 g / m², pretreated by 100W plasma for 3s) coating process: micro-gravure transfer coating (screen line number 200 lines / cm, vehicle speed 18 m / min) coating amount: 0.9±0.05 g / m² (dry film thickness 1.3 μm) gradient drying: pre-drying: 42℃ hot air, air speed 10 m / s, time 4 s (lock the surface layer 0.1-0.5 μm microporous) main drying: 58℃ pressure roller, pressure 0.35 MPa, time 3.5 s (form the middle layer 1-2 μm through hole) 4) The high-strength high-transparency antibacterial composite isolation glue liquid prepared in this embodiment for cultural relic backing paper has a water vapor permeability of 160 ml / min; a longitudinal tensile strength of 121.5 N / cm², a transverse tensile strength of 75.33 N / cm²; a longitudinal tear strength of 870.12 mN, a transverse tear strength of 986.45 mN; a bacteriostatic rate ≥99.99%, an antibacterial value ≥4.9. Example

[0035] 1) Combined dispersion liquid preparation: pore-forming agent: nano-sized silicon dioxide (50 nm) 4.5 g + nano-sized titanium dioxide (30 nm) 1.2 g + nano-sized calcium carbonate (80 nm, aspect ratio > 20) 2.8 g, antibacterial agent: modified berberine 1.6 g + ε-polylysine (food grade) 1.2 g + nano-zinc oxide (20 nm) 0.6 g, modifier: KH-550 silane coupling agent 0.8 g (total solid content 7.5%). Dispersion process: first ball milling dispersion (500 rpm, 2.0 h, zirconium oxide beads φ0.3 mm), then high pressure homogenization (800 bar, 0.8 h), solid content 24%, room temperature standing 12 h sedimentation rate <0.1% 2) Composite glue fusion: the above dispersion liquid is mixed with polyvinyl alcohol glue (polyvinyl alcohol, solid content 22%) according to the mass ratio of 1:4.5, 0.3% sodium alginate thickening agent is added, and the viscosity is adjusted to 170±10 cP.

[0036] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 40 g / m², pretreated by 100W plasma for 3s) coating process: micro-gravure transfer coating (screen line number 180 lines / cm, vehicle speed 15 m / min) coating amount: 1.0±0.05 g / m² (dry film thickness 1.5 μm) gradient drying: pre-drying: 45°C hot air, air speed 8 m / s, time 6 s (lock the surface layer 0.1-0.5 μm microporous) main drying: 60°C pressure roller, pressure 0.4 MPa, time 4 s (form the middle layer 1-2 μm through hole) 4) The high-strength, high-transparency, antibacterial composite isolation glue prepared in this embodiment for cultural relic backing paper has a water vapor transmission rate of 162 ml / min; a longitudinal tensile strength of 115.2 N N / cm², a transverse tensile strength of 78.83 N / cm²; a longitudinal tear strength of 864.89 mN, a transverse tear strength of 983.22 mN; a bacteriostatic rate of ≥99.95%, and an antibacterial value of ≥4.3. Example

[0037] 1) Combined dispersion liquid preparation: pore-forming agent: nano-sized silicon dioxide (50 nm) 3.5 g + nano-sized titanium dioxide (30 nm) 2.0 g + nano-sized calcium carbonate (80 nm, diameter-thickness ratio > 20) 2.5 g, antibacterial agent: modified berberine 2.0 g + ε-polylysine (food grade) 1.2 g + nano-zinc oxide (20 nm) 1.0 g, modifier: KH-550 silane coupling agent 1.0 g (total solid content 8.5%). Dispersion process: first ball milling dispersion (600 rpm, 1.5 h, zirconium oxide beads φ0.4 mm), then high-pressure homogenization (900 bar, 0.4 h), solid content 26%, room temperature standing for 12 h, sedimentation rate <0.1% 2) Composite glue fusion: the above dispersion liquid is mixed with polyvinyl alcohol glue (polyvinyl alcohol, solid content 23%) according to the mass ratio of 1:3.5, 0.4% sodium alginate thickening agent is added, and the viscosity is adjusted to 165±10 cP.

[0038] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 42 g / m2, pretreated by 120 W plasma for 3 s) coating process: micro gravure transfer coating (screen line number 190 lines / cm, line speed 16 m / min) coating amount: 0.85 ± 0.05 g / m2(dry film thickness 1.3 μm) gradient drying: pre-drying: 45 °C hot air, air speed 9 m / s, time 4 s (lock the surface layer 0.1-0.5 μm microporous) main drying: 60 °C pressure roller, pressure 0.35 MPa, time 2.5 s (form the middle layer 1-2 μm through hole) 4) The high-strength, high-transparency, antibacterial composite isolation glue solution prepared in this embodiment for cultural relic backing paper has a water vapor permeability of 167 ml / min; a longitudinal tensile strength of 128.75 N / cm2, a transverse tensile strength of 75.68 N / cm2; a longitudinal tear strength of 870.33 mN, a transverse tear strength of 978.45 mN; a bacteriostatic rate of ≥99.94%, and an antibacterial value of ≥4.4. Example

[0039] 1) Combined dispersion liquid preparation: pore-forming agent: nano-sized silicon dioxide (60 nm) 5.5 g + nano-sized titanium dioxide (40 nm) 2.0 g + nano-sized calcium carbonate (90 nm, diameter-thickness ratio > 25) 4.0 g, antibacterial agent: modified berberine 2.0 g + ε-polylysine (food grade) 1.2 g + nano-sized zinc oxide (20 nm) 1.0 g, modifier: KH-550 silane coupling agent 1 g (total solid content 7.8 %). Dispersion process: first ball milling dispersion (600 rpm, 2 h, zirconium oxide beads φ 0.4 mm), then high-pressure homogenization (900 bar, 0.8 h), solid content 26 %, room temperature standing for 12 h, sedimentation rate < 0.1 % 2) Composite glue solution fusion: mix the above dispersion liquid with polyvinyl alcohol glue solution (polyvinyl alcohol, solid content 23 %) according to a mass ratio of 1:3.8, add 0.35 % sodium alginate thickener, and adjust the viscosity to 165 ± 10 cP.

[0040] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 42 g / m2, pretreated by 120 W plasma for 2 s) coating process: micro gravure transfer coating (screen line number 190 lines / cm, line speed 16 m / min) coating amount: 0.83 ± 0.05 g / m2(dry film thickness 1.25 μm) gradient drying: pre-drying: 50 °C hot air, air speed 9 m / s, time 4 s (lock the surface layer 0.1-0.5 μm microporous) main drying: 65 °C pressure roller, pressure 0.32 MPa, time 2.8 s (form the middle layer 1-2 μm through hole) 4) The high-strength, high-transparency, antibacterial composite isolation glue solution prepared in this embodiment for cultural relic backing paper has a water vapor permeability of 164 ml / min; a longitudinal tensile strength of 129.20 N / cm², a transverse tensile strength of 75.10 N / cm²; a longitudinal tear strength of 862.50 mN, a transverse tear strength of 981.80 mN; a bacteriostasis rate of ≥99.94%, and an antibacterial value of ≥4.3. Embodiment

[0041] 1) Combined dispersion liquid preparation: porogen: nano-sized silicon dioxide (60 nm) 5.0 g + nano-sized titanium dioxide (40 nm) 1.5 g + nano-sized calcium carbonate (90 nm, diameter-thickness ratio > 25) 3.2 g, antibacterial agent: modified berberine 1.8 g + ε-polylysine (food grade) 1.4 g + nano-zinc oxide (20 nm) 0.8 g, modifier: KH-550 silane coupling agent 0.9 g (total solid content 7.8 %). Dispersion process: first ball milling dispersion (650 rpm, 1.8 h, zirconium oxide beads φ0.35 mm), then high-pressure homogenization (900 bar, 0.7 h), solid content 25%, room temperature standing for 12 h, sedimentation rate <0.1% 2) Composite glue solution fusion: mix the above dispersion liquid with polyvinyl alcohol glue solution (polyvinyl alcohol, solid content 23%) at a mass ratio of 1:4.0, add 0.35% sodium alginate thickener, and adjust the viscosity to 160±5 cP.

[0042] 3) Biomimetic coating and drying: substrate: acid-free paper (basis weight 48 g / m², pretreated by 110W plasma for 2.5 s) coating process: micro-gravure transfer coating (screen line number 210 lines / cm, line speed 19 m / min) coating amount: 0.92±0.05 g / m² (dry film thickness 1.35 μm) gradient drying: pre-drying: 45°C hot air, air speed 11 m / s, time 3.5 s (lock the surface layer 0.1-0.5 μm micropores) main drying: 60°C pressure roller, pressure 0.38 MPa, time 3.2 s (form the middle layer 1-2 μm through holes) 4) The high-strength, high-transparency, antibacterial composite isolation glue solution prepared in this embodiment for cultural relic backing paper has a water vapor permeability of 165 ml / min; a longitudinal tensile strength of 122.0 N / cm², a transverse tensile strength of 75.18 N / cm²; a longitudinal tear strength of 868.50 mN, a transverse tear strength of 985.20 mN; a bacteriostasis rate of ≥99.98%, and an antibacterial value of ≥4.8.

Claims

1. A preparation method of a high-strength, high-transparency, antibacterial composite isolation glue solution for cultural relic backing paper, characterized in that, Includes the following steps: Step 1, Pretreatment of backing paper substrate: Select acid-free Xuan paper / mulberry bark paper (basis weight 35-45g / m²) as substrate, and enhance the adhesion of the adhesive by plasma surface activation (power 100W, time 3s); Step 2, preparation of the combined dispersion: Nano-sized silica, nano-sized titanium dioxide, and nano-sized calcium carbonate are mixed in proportion; plant-derived antibacterial complex and KH-550 silane coupling agent (total solid content 8%) are added; then gradient dispersion is performed to obtain a stable dispersion; Step 3, preparation of composite adhesive: Mix the dispersion and polyvinyl alcohol adhesive (solid content 22%) at a mass ratio of 1:4; add 0.3% sodium alginate to adjust the viscosity to 160±10 cP; Step 4, biomimetic gradient coating: A single layer is coated on the substrate surface using a microgravure coating machine (180 lines / cm); the coating amount is precisely controlled to be 0.8±0.1g / m² (dry film thickness 1.2μm). Step 5, two-stage gradient drying: pre-drying: 40℃ hot air for 5s (fixing the surface layer 0.1-0.5μm antibacterial micropores); main drying: 55℃ pressure roller (0.3MPa, 3s) to form the middle layer 1-2μm air-permeable channels and the bottom layer 3-5μm fiber anchoring holes.

2. The method of claim 1, wherein: The pore-forming agent is a compound system composed of nano-sized silica, nano-sized titanium dioxide and nano-sized calcium carbonate in a mass ratio of (4-5):(1-1.5):(3-4).

3. The method of claim 1, wherein: The antibacterial agent is a plant-derived antibacterial complex comprising: berberine (40-50 wt%), ε-polylysine (30-40 wt%), and nano zinc oxide (10-20 wt%).

4. The method of claim 1, wherein: The separating adhesive is an aqueous solution of polyvinyl alcohol (PVA) with a solid content of 18-25%.

5. The method of claim 1, wherein: In step (3), the amount of adhesive applied is strictly controlled at 0.5-1.2 g / m², and the dry film thickness is 0.8-2 μm.

6. The method of claim 1, wherein: The final adhesive layer has a porosity of ≥40%, and the pore size is distributed in a gradient: the surface layer has a pore size of 0.1-0.5 μm (antibacterial barrier layer), the middle layer has a pore size of 1-2 μm (breathable channel), and the bottom layer has a pore size of 3-5 μm (fiber anchoring layer).

7. The method of claim 1, wherein: The tensile strength of the adhesive layer after drying is ≥100 N / cm², and the water vapor transmission rate is >160 ml / min.