Manufacturing method of aluminized polyester film

Abstract

The invention discloses a manufacturing method of an aluminized polyester film, which comprises the following steps: S1, preparing materials required by the aluminized polyester film, including a polyester base material layer, an aluminized functional layer and a surface protective coating; s2, carrying out two-way stretching molding on the polyester base material, pretreating the raw materials, and carrying out blending extrusion and heat setting treatment; s3, performing plasma-assisted corona treatment on the polyester base material; s4, the aluminized functional layer is subjected to a vacuum aluminizing process, UV glue is coated, and micro-embossing forming is conducted on the aluminized functional layer; and S5, surface functionalization coating is adopted, a coating solution is prepared, and coating and curing are conducted on the coating solution. Cross-scale synergistic improvement of mechanical, optical and thermal properties is achieved from molecular chain toughening to macrostructure optimization, the coating actively adapts to space environment changes through the double effects of chemical bond recombination and physical barriers, vacuum aluminum plating and nano spraying are combined, the limitation of a traditional single-function coating is broken through, and the coating is more suitable for large-scale production. The comprehensive performance reaches the NASA multilayer composite membrane level, and the cost is reduced by 40%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum-plated polyester film processing, in particular to a manufacturing method of aluminum-plated polyester film. BACKGROUND

[0002] Spacecrafts are faced with extreme thermal environment (-180℃ to +150℃), high-energy particle radiation (ultraviolet, proton, electron), atomic oxygen erosion and micro-meteoroid impact during on-orbit operation. The thermal control system needs to maintain the temperature stability of the equipment through radiation heat dissipation and reflection regulation and control, and the aluminum-plated polyester film is the core material of the secondary surface mirror.

[0003] The aluminum-plated polyester film in the prior art has the following problems: 1. Insufficient thermal stability of the base material. The traditional polyester (PET) base material is prone to molecular chain rupture or crystallinity change under extreme temperature change, resulting in curling and delamination. For example, the thermal shrinkage rate of unmodified PET film is 1.2% at 150℃, which is much higher than the threshold of 0.5% required by spacecrafts. In addition, the anisotropic structure formed by the conventional biaxial stretching process aggravates stress concentration, and micro-cracks are easily induced after long-term service; 2. Limited bonding force and optical efficiency of the plated layer. The traditional vacuum aluminum plating process uses a flat substrate, and the bonding force between the aluminum layer and the polyester interface is 2-3 N / cm (ASTM D3359 test standard), which is prone to peeling after long-term thermal cycling. At the same time, the mirror reflectivity of the flat aluminum film to the incident light is only 88-90%, which cannot meet the demand of high reflectivity for deep space exploration; 3. Insufficient durability of the protective coating. The existing polyurethane or epoxy resin protective layer is prone to pulverization under atomic oxygen erosion, and lacks self-repairing ability. For example, the reflectivity of the unmodified coating decreases by more than 5% after 500 hours of exposure in low earth orbit environment.

[0004] Based on the above-mentioned technical problems, it is necessary to develop a manufacturing method of aluminum-plated polyester film. SUMMARY

[0005] The purpose of the present application is to provide a manufacturing method of aluminum-plated polyester film to solve the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a manufacturing method of aluminum-plated polyester film, comprising the following method steps: S1, preparing the materials required for the aluminum-plated polyester film, including a polyester base material layer, an aluminum-plated functional layer and a surface protective coating; S2, biaxially stretching the polyester base material, pretreating and blending the raw material, extruding and heat setting; S3, performing plasma-assisted corona treatment on the polyester base material; S4, using vacuum aluminum plating process on the aluminum-plated functional layer, coating UV glue and micro-embossing it; S5, using surface functionalization coating, preparing the coating solution and coating and curing it.

[0007] Preferably, the polyester substrate layer in step S1 includes a main material: high-purity PET chip (1000-2000 parts), with a specific viscosity of 0.65-0.85 dL / g and a crystallinity controlled at 35-40% to balance the mechanical and thermal stability; a toughening agent: polyisobutylene succinimide (PIBSI, 10-20 parts), which inhibits PET crystallization shrinkage through molecular entanglement of its long-chain structure; a coupling agent: cyano acrylate (5-10 parts), used to improve the interfacial bonding force of PET and nano-filler; and a nano-filler: modified montmorillonite particles (2-4 parts, diameter-thickness ratio ≥200) and hydroxylated nano-boron nitride (BN, 1-3 parts), the former blocks crack propagation, and the latter has a thermal conductivity of 400-500 W / (m·K) to disperse local thermal stress.

[0008] Preferably, the aluminum-plated functional layer in step S1 includes a UV-cured glue base: a triangular prism-shaped protruding structure (height 5-8 μm, spacing 10-15 μm) is adopted to improve the reflectivity of incident light to 95% through geometric optical effects; and nano-spherical alumina (50-100 nm) is sprayed on the surface of the aluminum layer to form a micro-nano rough structure.

[0009] Preferably, the surface protection coating in step S1 includes a base material: polyurethane acrylate (50%), with a glass transition temperature of -30°C, used to adapt to deformation in a wide temperature range; and functional additives: cyclotriphosphazene copolymer (30%) and vinyl-POSS (20%), the former generates a phosphate glass layer at high temperature, and the latter forms a Si-O-Si self-repairing network under ultraviolet irradiation.

[0010] Preferably, in the raw material pretreatment in step S2, the PET chip and additives are vacuum dried at 120°C for 12 hours, with a water content of ≤50 ppm; in the blending and extrusion, a double-screw extruder (length-diameter ratio 36:1) is adopted, with temperature zoning at 280-300°C, a melt pressure of 12-15 MPa, and a cast sheet thickness of 200-300 μm; and in the heat setting treatment, the temperature is controlled at 230-240°C, the relaxation rate is 5-8%, and the thermal shrinkage rate is ≤0.5%.

[0011] Preferably, the corona treatment device in step S3 is a high-frequency pulse power supply (frequency 50 kHz), with an electrode spacing of 2-3 mm, a nitrogen atmosphere, a power of 15-20 kW, and a processing speed of 10-15 m / min, and the surface energy is improved to 50-55 mN / m4.

[0012] Preferably, in step S4, the UV glue is coated using a gravure coater, with a wet film thickness of 2-3 μm; and in the micro-embossing forming, the steel roller temperature is 80°C, and the pressure is 5-8 kN, forming a triangular prism-shaped protruding structure.

[0013] Preferably, the coating solution in step S5 is prepared using ethyl acetate and acetone (mass ratio 7:3), with a solid content of 30%, a dispersion process of a high-speed shearing emulsifier (rotation speed 3000 rpm), a dispersion time of 30 minutes; in the coating and curing process, the coating method is micro-gravure coating (roller diameter 50 mm, line pressure 20 N / cm), and the curing conditions are UV intensity 800 mJ / cm 2 , infrared heating 60℃, and curing time 3-5 seconds.

[0014] Compared with the prior art, the present application has the following advantages:

[0015] (1) In the present application, polyisobutylene succinimide (PIBSI) is innovatively introduced as a toughening agent, and the long-chain block structure thereof inhibits stress concentration in the PET crystallization process through intermolecular entanglement, and the heat conduction property (400-500 W / (m·K)) of the hydroxylated boron nitride (BN) is combined to achieve rapid heat diffusion, so that the thermal shrinkage rate of the substrate is reduced to below 0.5% (the traditional PET is 1.2%);

[0016] (2) In the present application, a synergistic process of longitudinal stretching (80-90℃, 3.5-4.0 times) and transverse stretching (100-110℃, 3.0-3.5 times) is adopted to form an isotropic network structure, reduce residual stress, and realize uniform dispersion of nano-montmorillonite (diameter-thickness ratio≥200) through melt blending-ultrasonic oscillation, physically block the crack propagation path, and increase the bending fatigue resistance by 3 times;

[0017] (3) In the present application, a UV-cured adhesive is coated on the surface of the substrate and is embossed to form a triangular prism-shaped protrusion (height 5-8μm, spacing 10-15μm), which prolongs the reflection path of incident light through geometric optical effect, and the solar reflectivity is increased to more than 95% (the traditional planar aluminum-coated film is 88%), and the structure simultaneously increases the mechanical interlocking action between the aluminum layer and the substrate, and the bonding force reaches 6-8N / cm;

[0018] (4) In the present application, the protective coating is compounded by cyclotriphosphazene copolymer and vinyl-POSS at a mass ratio of 3:2 to form a double-response mechanism, the cyclotriphosphazene copolymer: generates a phosphate glass layer at high temperature to block the penetration of atomic oxygen (mass loss rate≤0.05%), and the vinyl-POSS: ultraviolet radiation initiates ring-opening reaction to form a Si-O-Si crosslinked network to repair microcracks, and the reflectivity attenuation is≤2% after 5000 hours of ultraviolet aging. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The present application is a whole method step block diagram. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application.

[0021] Please refer to Figure 1 An embodiment provided by the present application is a manufacturing method of an aluminum-plated polyester film, comprising the following method steps: S1, preparing materials required by the aluminum-plated polyester film, including a polyester base material layer, an aluminum-plated functional layer and a surface protection coating layer; S2, biaxially stretching the polyester base material into a shape, pretreating and blending extruding and heat setting the raw material; S3, performing plasma-assisted corona treatment on the polyester base material; S4, adopting a vacuum aluminum plating process on the aluminum-plated functional layer, coating UV glue and performing micro-embossing on the UV glue; and S5, adopting surface functionalization coating, preparing a coating solution and coating and curing the coating solution.

[0022] Further, the polyester base material layer in the step S1 comprises a main material: high-purity PET chip (1000-2000 parts), with a specific viscosity of 0.65-0.85 dL / g and a crystallinity controlled at 35-40% to balance the mechanical property and thermal stability; a toughening agent: polyisobutylene succinimide (PIBSI, 10-20 parts), which suppresses PET crystallization shrinkage through molecular entanglement of long-chain structure; a coupling agent: cyanoacrylate (5-10 parts), used to improve the interfacial bonding force between PET and nano-filler; and a nano-filler: modified montmorillonite particles (2-4 parts, with a diameter-thickness ratio ≥200) and hydroxylated nano-boron nitride (BN, 1-3 parts), the former blocks crack propagation and the latter has a thermal conductivity of 400-500 W / (m·K) and is used to disperse local thermal stress.

[0023] Further, the aluminum-plated functional layer in the step S1 comprises a UV-cured glue base: a triangular prism-shaped protruding structure (with a height of 5-8 μm and a spacing of 10-15 μm), which improves the reflectivity of incident light to 95% through geometric optical effect; and nano-spherical alumina (50-100 nm), which is sprayed on the surface of the aluminum layer to form a micron-nanometer level rough structure.

[0024] Further, the surface protection coating layer in the step S1 comprises a base material: polyurethane acrylate (50%), with a glass transition temperature of -30 ℃ and used to adapt to deformation in a wide temperature range; and functional additives: cyclotriphosphazene copolymer (30%) and vinyl-POSS (20%), the former generates a phosphate glass layer through high-temperature decomposition and the latter forms a Si-O-Si self-repairing network through ultraviolet irradiation.

[0025] Further, in the step S2, the PET chips and the additives are vacuum dried at 120℃ for 12 hours, and the water content is less than or equal to 50ppm; in the blending and extruding, a double-screw extruder (length-diameter ratio 36:1) is used, the temperature partition is 280-300℃, the melt pressure is 12-15MPa, and the casting thickness is 200-300μm; in the heat setting, the temperature is controlled at 230-240℃, the relaxation rate is 5-8%, and the heat shrinkage rate is less than or equal to 0.5%.

[0026] Further, in the step S3, the corona treatment device is a high-frequency pulse power supply (frequency 50kHz), the electrode spacing is 2-3mm, the process parameters are nitrogen atmosphere, power 15-20kW, and the processing speed is 10-15m / min, and the surface energy is increased to 50-55mN / m4.

[0027] Further, in the step S4, the UV glue is coated by using a gravure coater, and the wet film thickness is 2-3μm; in the micro-embossing, the steel roller temperature is 80℃, and the pressure is 5-8kN, so as to form a triangular prism convex structure.

[0028] Further, in the step S5, the coating solution is prepared by using ethyl acetate and acetone (mass ratio 7:3), the solid content is 30%, the dispersion process is a high-speed shearing emulsifier (rotating speed 3000rpm), and the dispersion time is 30 minutes; in the coating and curing, the coating method is microgravure coating (roller diameter 50mm, linear pressure 20N / cm), and the curing conditions are UV intensity 800mJ / cm 2 , infrared heating 60℃, and curing time 3-5 seconds.

[0029] Please refer to Figure 1 , another embodiment provided by the present application is as follows:

[0030] I. Material composition

[0031] Polyester substrate layer

[0032] Formulation: PET chips 1500 parts, polyisobutylene succinimide (PIBSI) 15 parts, cyano acrylate 8 parts, nano-modified montmorillonite particles 3 parts, and hydroxylated nano-boron nitride (BN) 2 parts.

[0033] Function: PIBSI inhibits crystallization stress, BN improves thermal conductivity (0.35W / (m·K)), and montmorillonite enhances crack propagation resistance.

[0034] Aluminum-coated functional layer

[0035] Structure: UV-cured glue base (thickness 2.5μm, triangular prism convex height 6μm), aluminum layer thickness Surface spraying of nano-spherical alumina (particle size 80nm).

[0036] Coating sheet resistance: 1.8 Ω / □, solar reflectance after optimization of the reflection path increased to 96.2%.

[0037] Surface protective coating

[0038] Formulation: polyurethane acrylate (50%), cyclotriphosphazene copolymer (30%), vinyl-POSS (20%), forming a self-healing network.

[0039] Coating thickness: 3.0 ± 0.2 μm, hardness after curing up to 3H (pencil hardness test).

[0040] II. Preparation process flow

[0041] Step 1: biaxial stretching of the polyester substrate

[0042] Melt extrusion

[0043] The raw materials were blended and extruded at 290 °C, with a cast thickness of 250 μm and a screw rotation speed of 15 r / min.

[0044] Longitudinal stretching

[0045] Temperature 85 °C, stretching ratio 3.8 times, controlled tension 200 N / m.

[0046] Transverse stretching

[0047] Temperature 105 °C, stretching ratio 3.2 times, final substrate thickness 18 μm.

[0048] Step 2: plasma surface treatment

[0049] Equipment parameters: nitrogen atmosphere, power 18 kW, frequency 50 kHz, treatment time 30 seconds, surface energy increased to 52 mN / m.

[0050] Step 3: vacuum deposition of the aluminum base

[0051] After coating with the UV glue, the micro-embossing roller (line pressure 50 N / cm) was used to form the triangular pyramid projections, with a UV curing energy of 600 mJ / cm 2 .

[0052] Deposition of aluminum

[0053] Vacuum 3 x 10-3P a , aluminum evaporation temperature 1250 °C, deposition rate 25 nm / s, aluminum wire purity 99.99%.

[0054] Step 4: surface protective coating

[0055] Slot coating: solid content 30%, coating speed 8 m / min, film thickness uniformity deviation ± 0.15 μm.

[0056] Dual curing: UV intensity 800 mJ / cm 2 ( wavelength 365 nm), 60℃ post-curing for 2 hours 24.

[0057] Step 5: Punching treatment

[0058] Punching parameters: through-hole diameter 2mm, row distance 30mm, column distance 30mm, staggered diamond distribution, hole roundness ≤0.08mm.

[0059] Equipment: punch pin mold (pressure 0.5MPa), organic pad to prevent plating scratches.

[0060] III. Performance verification

[0061] 1. Thermal stability test

[0062] Conditions: -180℃ (liquid nitrogen) to +150℃ (oven) cycle 100 times.

[0063] Results: thermal shrinkage rate 0.38% (traditional PET 1.2%); no cracking or curling, tensile strength retention rate 96.5%.

[0064] 2. Optical performance test

[0065] Solar reflectance: 96.2% (ASTM E903 standard), infrared emissivity 0.07 (FTIR test).

[0066] Radiation resistance: after 1MeV proton irradiation (flux 1×10 15 / cm 2 ), reflectance attenuation ≤1.5%.

[0067] 3. Environmental resistance test

[0068] Atomic oxygen erosion: flux 1×10 16 atoms / cm 2 , mass loss rate 0.04% (traditional coating 0.2%).

[0069] Bending fatigue: radius 5mm, after 5000 cycles, the coating has no peeling (ASTM D2176 standard)

[0070]

[0071] In summary, the application realizes the cross-scale synergistic improvement of mechanical, optical and thermal properties by toughening from molecular chain to macroscopic structure optimization, the coating actively adapts to changes in space environment through the dual action of chemical bond reorganization and physical barrier, and the combination of vacuum aluminum plating and nano spraying breaks through the limitations of traditional single functional coating, the comprehensive performance reaches the level of NASA multilayer composite film, and the cost is reduced by 40%.

[0072] It has to be noted that, in the present document, the terms "first", "second", etc. merely serve to identify a subject or action, without necessarily requiring or implying any such actual relationship or order between such subjects or actions. Moreover, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusions, such that a process, method, article, or apparatus that comprises a list of elements does not include those elements solely, but can include other elements not expressly listed, or can include elements inherent in such process, method, article, or apparatus.

[0073] While embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, combinations, and variations of the embodiments can be undertaken without departing from the spirit and scope of the present application, which is defined by the appended claims and their equivalents.

Claims

1. A method for producing an aluminized polyester film, characterized in that: The method comprises the following steps: S1. Prepare the materials required for the aluminized polyester film, including a polyester base layer, an aluminized functional layer, and a surface protective coating; S2, biaxially stretching the polyester substrate, pre-treating the raw materials, and performing co-extrusion and heat setting treatments; S3, performing plasma-assisted corona treatment on the polyester substrate; S4. Vacuum aluminizing process is used for the aluminized functional layer, UV adhesive is applied and micro-embossing is performed; S5. Using surface functional coating, the coating solution is prepared and coated and cured.

2. The method for manufacturing an aluminized polyester film according to claim 1, wherein: In step S1, the polyester substrate layer includes a main material: high-purity PET chips (1000-2000 parts), an intrinsic viscosity of 0.65-0.85 dL / g, and a crystallinity controlled at 35-40% to balance mechanical and thermal stability; a toughening agent: polyisobutylene succinimide (PIBSI, 10-20 parts), whose long-chain structure inhibits PET crystallization shrinkage through molecular entanglement; a coupling agent: cyanoacrylate (5-10 parts), which is used to enhance the interfacial bonding strength between PET and nanofillers; and nanofillers: modified montmorillonite particles (2-4 parts, aspect ratio ≥200) and hydroxylated nano-boron nitride (BN, 1-3 parts), the former of which blocks crack propagation, and the latter of which has a thermal conductivity of 400-500 W / (m·K) and is used to disperse local thermal stress.

3. The method for manufacturing an aluminized polyester film according to claim 1, wherein: The aluminum-plated functional layer in step S1 includes a UV-curing adhesive base: a triangular prism-shaped protrusion structure (height 5-8 μm, spacing 10-15 μm) is used to increase the reflectivity of incident light to 95% through geometric optical effects; nano-spherical aluminum oxide (50-100 nm) is sprayed on the surface of the aluminum layer to form a micron-nanoscale rough structure.

4. The method for manufacturing an aluminized polyester film according to claim 1, wherein: The surface protective coating in step S1 includes a base material: polyurethane acrylate (50%), with a glass transition temperature of -30°C, which is used to adapt to deformation over a wide temperature range; functional additives: cyclotriphosphazene copolymer (30%) and vinyl-POSS (20%), the former decomposes at high temperature to form a phosphate glass layer, and the latter forms a Si-O-Si self-healing network under ultraviolet irradiation.

5. The method for manufacturing an aluminized polyester film according to claim 1, wherein: In the raw material pretreatment of step S2, the PET slices and additives are vacuum dried at 120° C. for 12 hours, with a moisture content of ≤50 ppm; a twin-screw extruder (length-to-diameter ratio 36:1) is used for the blending extrusion, with a temperature zone of 280-300° C., a melt pressure of 12-15 MPa, and a sheet thickness of 200-300 μm; and the temperature of the heat setting treatment is controlled at 230-240° C., a relaxation rate of 5-8%, and a thermal shrinkage rate of ≤0.5%.

6. The method for manufacturing an aluminized polyester film according to claim 1, wherein: In step S3, the corona treatment device is a high-frequency pulse power supply (frequency 50kHz), the electrode spacing is 2-3mm, the process parameters are nitrogen atmosphere, power 15-20kW, treatment speed 10-15m / min, and the surface energy is increased to 50-55mN / m4.

7. The method for manufacturing an aluminized polyester film according to claim 1, wherein: In step S4, the UV adhesive is coated using a gravure coater with a wet film thickness of 2-3 μm; in the micro-embossing, the steel roller temperature is 80° C. and the pressure is 5-8 kN to form a triangular prism convex structure.

8. The method for manufacturing an aluminized polyester film according to claim 1, wherein: In step S5, the coating solution is prepared by using ethyl acetate and acetone (mass ratio 7:3), with a solid content of 30%, and the dispersion process is a high-speed shear emulsifier (rotation speed 3000 rpm), and the dispersion time is 30 minutes; the coating and curing are carried out by micro-gravure coating (roller diameter 50 mm, linear pressure 20 N / cm), and the curing condition is UV intensity 800 mJ / cm 2 , infrared heating 60℃, curing time 3-5 seconds.

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