Piezoelectric phase change six-layer moisture-proof corrugated board and preparation method thereof

Abstract

The invention provides a piezoelectric phase change six-layer moisture-proof corrugated board. The corrugated board is of a six-layer structure sequentially compounded from outside to inside, wherein an antistatic piezoelectric layer is formed by lead zirconate titanate nanoparticles and polyvinylidene fluoride through electrostatic spinning; the moisture-proof functional layer is formed by compounding a polyurethane emulsion, a fluorine-containing compound with the carbon atom number larger than or equal to 6 and hydroxypropyl chitosan, the hydrophobic adhesive interface layer is formed by mixing acrylic resin and TiO2 nanoparticles and then conducting UV curing, and the contact angle is larger than or equal to 110 degrees; the fine honeycomb composite corrugated layer is formed by arranging G corrugations, F corrugations and V-shaped compression-resistant corrugations in a staggered manner, gaps among corrugation teeth are filled with nano silicon dioxide aerogel containing more than or equal to 30% of regenerated cellulose, and the water absorption rate is less than or equal to 1.5%; the phase change temperature control layer is composed of a paraffin / expanded graphite shape-stabilized phase change material, and the paraffin adsorption rate is larger than or equal to 90%; the nano reinforced base material layer is prepared from 60% of softwood pulp, 40% of hibiscus cannabinus stem pulp and red seaweed gel modified nano calcium carbonate. A dynamic damp-proof, compression-resistant and temperature-control cooperative system is realized, and the comprehensive cost is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of corrugated cardboard technology, and in particular to a piezoelectric phase change six-layer moisture-proof corrugated cardboard and its preparation method. Background Technology

[0002] Chinese Patent Publication No. CN204894633U, published on December 23, 2015, discloses a corrugated cardboard comprising an outer linerboard, a waterproof adhesive layer, a corrugated core, an adhesive layer, and an inner linerboard. The corrugated core is composed of hexagonal cores, each containing a central circular core and several smaller circular cores tangent to the outer circumference of the central circular core. The advantages of this invention are: the waterproof adhesive layer provides moisture-proof and damp-proof properties; and the multi-layered composite core structure enhances the cushioning capacity of the corrugated cardboard. The existing technology has the following drawbacks: 1. Degraded mechanical properties: the structure of a hexagonal paper core nested around a central circle plus eight smaller circular paper cores complicates the stress transmission path; 2. Ineffective moisture protection: the waterproof adhesive layer is only placed between the outer linerboard and the corrugated paper core, but moisture mainly penetrates the inner layer through the seams and staples of the carton. The interconnected pores formed by the hexagonal and circular paper cores provide diffusion paths for water molecules; 3. Inability to mass-produce: the core layer processing requires excessively high precision, resulting in low material utilization. Given these circumstances, improvements are urgently needed. Summary of the Invention

[0003] Based on this, the purpose of this invention is to provide a piezoelectric phase change six-layer moisture-proof corrugated cardboard and its preparation method, which realizes a dynamic moisture-proof, pressure-resistant, and temperature-controlled synergistic system, and effectively reduces the overall cost.

[0004] This invention provides a piezoelectric phase change six-layer moisture-proof corrugated cardboard, with a six-layer structure laminated sequentially from the outside to the inside:

[0005] Antistatic layer: formed by electrospinning lead zirconate titanate nanoparticles and polyvinylidene fluoride, with a thickness of 0.05-0.1 mm and a surface resistivity ≤10. 6 Ω;

[0006] Moisture-proof functional layer: composed of polyurethane emulsion, fluorinated compounds with ≥6 carbon atoms and hydroxypropyl chitosan, with a thickness of 0.1-0.3mm;

[0007] Hydrophobic adhesive interface layer: formed by UV curing of acrylic resin and TiO2 nanoparticles, with a thickness of 0.05-0.1 mm and a contact angle ≥110°;

[0008] Micro-honeycomb composite corrugated layer: composed of alternating G-flute, F-flute and V-type compressive corrugations, with the gaps between the corrugations filled with nano-silica aerogel containing ≥30% regenerated cellulose and a water absorption rate ≤1.5%;

[0009] Phase change temperature control layer: composed of paraffin / expanded graphite shaped phase change material, with paraffin adsorption rate ≥90%, phase change enthalpy ≥180J / g, and thickness 0.2-0.4mm;

[0010] Nano-reinforced substrate layer: made of 60% softwood pulp, 40% kenaf stalk pulp, and red seaweed gum modified nano-calcium carbonate, with a basis weight of 90 g / m³. 2 .

[0011] Preferably, the lead zirconate titanate nanoparticles are set at 60-80 parts, the polyvinylidene fluoride is set at 20-40 parts; the mass ratio of the polyurethane emulsion to the fluorinated compound is 7:3; the hydroxypropyl chitosan is set at 5-8 parts; the acrylic resin is set at 50-75 parts; the TiO2 nanoparticles have a particle size of 20-50 nm and are set at 3-5 parts; the G-flute has a flute height of 0.5-0.6 mm, the F-flute has a flute height of 0.7-0.9 mm, and the V-shaped anti-compression corrugated corrugation has a flute height of 1.8-2.0 mm; and the amount of red seaweed-modified nano-calcium carbonate added is 8-12%.

[0012] Preferably, the antistatic electric layer is polarized with an electric field strength of 15 kV / mm for 30 min, and a piezoelectric constant d. 33 ≥25pC / N.

[0013] Preferably, the expanded graphite pore size in the phase change temperature control layer is 50-100μm, and the phase change temperature range is 5-35℃.

[0014] Preferably, the TiO2 nanoparticles in the hydrophobic adhesive interface layer generate hydroxyl radicals under ultraviolet light irradiation, resulting in a formaldehyde degradation rate of ≥95%.

[0015] Preferably, before the micro-honeycomb composite ribbed layer aerogel is filled, the surface of the ribs is formed with micro-nano-level pits by reactive ion etching.

[0016] Preferably, the total thickness of the six-layer structure is 3.2±0.3mm, wherein the antistatic layer accounts for 3%, the moisture-proof functional layer accounts for 7%, the hydrophobic adhesive interface layer accounts for 5%, the micro-honeycomb composite corrugated layer accounts for 55%, the phase change temperature control layer accounts for 10%, and the nano-reinforced substrate layer accounts for 20%.

[0017] Preferably, the moisture-proof functional layer has a moisture permeability of ≤2.0×10 at 25℃. 1 g / 24h·m 2 ·10 3 Pa, moisture permeability at 35℃ ≥5.0×10 1 g / 24h·m 2 ·10 3 Pa, moisture permeability at 5℃ ≤1.5×101 g / 24h·m 2 ·10 3 Pa.

[0018] A method for preparing corrugated cardboard including any one of the above 1-8, comprising the following steps:

[0019] S1. Substrate treatment: The surface of the nano-reinforced substrate layer is subjected to low-temperature plasma pretreatment with a power of 1.5kW for 30s.

[0020] S2, Phase change layer composite: A mixture of molten paraffin / expanded graphite is coated onto a substrate layer and hot-pressed at 80°C;

[0021] S3, Corrugated Layer Bonding: A hydrophobic adhesive interface layer is coated on the phase change temperature control layer through a slit extrusion coating head. The wet film thickness of the hydrophobic adhesive interface layer is 50±5μm. The micro-honeycomb composite corrugated layer is then pressed together. The coating accuracy of the hydrophobic adhesive interface layer is controlled to be ±3μm.

[0022] S4. Moisture-proof layer spraying: The moisture-proof functional layer is applied to the outer surface of the corrugated layer using a micro-pore spraying device with a pore size of 50μm, and the spraying pressure is 0.3-0.5MPa;

[0023] S5. Piezoelectric layer coating: PZT / PVDF electrospinning solution containing 0.5-1.0 wt% carbon nanotubes is coated on the outside of the moisture-proof functional layer. The electrospinning voltage is 20 kV and the receiving distance is 15 cm. 0.5-1.0 wt% carbon nanotubes are added to the electrospinning solution to form a three-dimensional conductive network.

[0024] S6. Curing: Pre-dry with hot air at 80℃ for 2 minutes, then UV cured at 800-1000 mJ / cm². 2 .

[0025] The beneficial effects of this invention are as follows: An antistatic layer is provided to convert transport vibration energy into electrical energy, driving a temperature-sensitive response and reducing electrostatic damage rate; a moisture-proof functional layer is provided, with polyurethane / fluorinated compound / chitosan composite achieving dynamic adjustment of moisture permeability; a hydrophobic adhesive interface layer is provided, with TiO2 photocatalytic degradation of formaldehyde ≥95%, UV curing contact angle ≥110°, combining self-cleaning and waterproofing; a micro-honeycomb composite corrugated layer is provided, filled with aerogel, with a water absorption rate ≤1.5%, and with a G / F / V corrugated composite design, the edge compressive strength reaches 7800 N / m; a phase change temperature control layer is provided, with paraffin / graphite shaped phase change material, phase change enthalpy ≥180 J / g, temperature control fluctuation rate <±1.5℃, lower than the industry average; a nano-reinforced substrate layer is provided, with 40% kenaf whole stalk pulp, plus nano-calcium carbonate to reduce carbon footprint, with a basis weight of 90 g / m³. 2 It has a biodegradability rate of ≥80%; it achieves a dynamic moisture-proof, pressure-resistant, and temperature-controlled synergistic system, and effectively reduces overall costs. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the present invention.

[0027] The attached figures are labeled as follows: antistatic layer 10, moisture-proof functional layer 11, hydrophobic adhesive interface layer 12, micro-honeycomb composite corrugated layer 13, and nano-reinforced substrate layer 15. Detailed Implementation

[0028] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Please refer to Figure 1 As shown, a piezoelectric phase change six-layer moisture-proof corrugated cardboard has a six-layer structure laminated sequentially from the outside to the inside:

[0031] Antistatic layer 10: formed by electrospinning lead zirconate titanate nanoparticles and polyvinylidene fluoride, with a thickness of 0.05-0.1 mm and a surface resistivity ≤10. 6 Ω; Antistatic layer 10 is polarized, electric field strength 15kV / mm, time 30min, piezoelectric constant d 33 ≥25pC / N; piezoelectric power generation drives temperature-sensitive response, solving the problem of condensation in cold chain packaging;

[0032] Moisture-proof functional layer 11: composed of polyurethane emulsion, fluorinated compounds with ≥6 carbon atoms, and hydroxypropyl chitosan, with a thickness of 0.1-0.3 mm and a moisture permeability of ≤2.0×10 at 25℃. 1 g / 24h·m 2 ·10 3 Pa; the moisture-proof functional layer 11 has a moisture permeability ≥ 5.0 × 10 at 35℃. 1 g / 24h·m 2 ·10 3 Pa, moisture permeability at 5℃ ≤1.5×10 1 g / 24h·m 2 ·10 3 Pa;

[0033] Hydrophobic adhesive interface layer 12: formed by UV curing of acrylic resin and TiO2 nanoparticles, with a thickness of 0.05-0.1 mm and a contact angle ≥110°; the TiO2 nanoparticles in the hydrophobic adhesive interface layer 12 generate hydroxyl radicals under UV irradiation, resulting in a formaldehyde degradation rate ≥95%.

[0034] Micro-cell composite corrugated layer 13: It is composed of alternating G-flute, F-flute and V-type compression-resistant corrugations, and the gaps between the corrugations are filled with nano-silica aerogel containing ≥30% regenerated cellulose, with a water absorption rate ≤1.5%; Before the aerogel is filled, the surface of the corrugations of the micro-cell composite corrugated layer 13 is formed with micro-nano-level pits by reactive ion etching; This solves the problem of delamination of the composite core layer under humid and hot conditions;

[0035] Phase change temperature control layer 14: composed of paraffin / expanded graphite shaped phase change material, with paraffin adsorption rate ≥90%, phase change enthalpy ≥180J / g, and thickness 0.2-0.4mm; the expanded graphite pore size in phase change temperature control layer 14 is 50-100μm, and the phase change temperature range is 5-35℃; it delays the internal temperature rise caused by sudden external temperature changes by ≥4h, and reduces the loss rate from 15% to 5%;

[0036] Nano-reinforced substrate layer 15: made of 60% softwood pulp, 40% kenaf stalk pulp, and red seaweed gum modified nano-calcium carbonate, with a quantitative content of 90 g / m³. 2 .

[0037] The lead zirconate titanate nanoparticles are set at 60-80 parts, the polyvinylidene fluoride is set at 20-40 parts; the mass ratio of the polyurethane emulsion to the fluorinated compound is 7:3; the hydroxypropyl chitosan is set at 5-8 parts; the acrylic resin is set at 50-75 parts; the TiO2 nanoparticles have a particle size of 20-50 nm and are set at 3-5 parts; the G-flute has a flute height of 0.5-0.6 mm, the F-flute has a flute height of 0.7-0.9 mm, and the V-shaped anti-compression corrugated corrugation has a flute height of 1.8-2.0 mm; the amount of red seaweed gum-modified nano-calcium carbonate added is 8-12%.

[0038] The total thickness of the six-layer structure is 3.2±0.3mm, wherein the antistatic layer 10 accounts for 3%, the moisture-proof functional layer 11 accounts for 7%, the hydrophobic adhesive interface layer 12 accounts for 5%, the micro-honeycomb composite corrugated layer 13 accounts for 55%, the phase change temperature control layer 14 accounts for 10%, and the nano-reinforced substrate layer 15 accounts for 20%.

[0039] In this embodiment, an antistatic layer is provided to convert transport vibration energy into electrical energy, driving a temperature-sensitive response and reducing electrostatic damage rate; a moisture-proof functional layer is provided, with polyurethane / fluorinated compound / chitosan composite achieving dynamic adjustment of moisture permeability; a hydrophobic adhesive interface layer is provided, with TiO2 photocatalytic degradation of formaldehyde ≥95%, UV curing contact angle ≥110°, and both self-cleaning and waterproof properties; a micro-honeycomb composite corrugated layer is provided, filled with aerogel, with a water absorption rate ≤1.5%, and with a G / F / V corrugated composite design, the edge compressive strength reaches 7800 N / m; a phase change temperature control layer is provided, with paraffin / graphite shaped phase change material, phase change enthalpy ≥180 J / g, and temperature control fluctuation rate <±1.5℃, lower than the industry average; a nano-reinforced substrate layer is provided, with 40% kenaf whole stalk pulp, plus nano-calcium carbonate to reduce carbon footprint, with a basis weight of 90 g / m³. 2 It has a biodegradability rate of ≥80%; it achieves a dynamic moisture-proof, pressure-resistant, and temperature-controlled synergistic system, and effectively reduces overall costs.

[0040] A method for preparing corrugated cardboard including any one of the above 1-8, comprising the following steps:

[0041] S1. Substrate treatment: The surface of the nano-reinforced substrate layer 15 is subjected to low-temperature plasma pretreatment with a power of 1.5kW for 30s. The plasma pretreatment improves the fiber bonding force and the adsorption rate of nano-calcium carbonate reaches 95%.

[0042] S2, Phase Change Layer Composite: Molten paraffin / expanded graphite mixture is coated onto the substrate layer and hot-pressed at 80℃; the hot pressing of the phase change layer at 80℃ avoids paraffin leakage, and the thickness fluctuation rate is <5%.

[0043] S3, Corrugated Layer Bonding: A hydrophobic adhesive interface layer 12 is coated on the phase change temperature control layer 14 through a slit extrusion coating head. The wet film thickness of the hydrophobic adhesive interface layer 12 is 50±5μm. The micro-honeycomb composite corrugated layer 13 is then pressed together. The coating accuracy of the hydrophobic adhesive interface layer 12 is controlled to ±3μm, and the uniformity of the adhesive layer avoids local stress concentration.

[0044] S4. Moisture-proof layer spraying: The moisture-proof functional layer 11 is coated on the outer surface of the corrugated layer using a 50μm micro-pore spraying device at a spraying pressure of 0.3-0.5MPa. The 50μm micro-pore spraying ensures that the moisture-proof layer thickness fluctuation rate is ≤5%, thus improving the moisture permeability stability.

[0045] S5. Piezoelectric layer lamination: A PZT / PVDF electrospinning solution containing 0.5-1.0 wt% carbon nanotubes is lamination over the moisture-proof functional layer 11. The electrospinning voltage is 20 kV, and the receiving distance is 15 cm. Adding 0.5-1.0 wt% carbon nanotubes to the electrospinning solution forms a three-dimensional conductive network with a surface resistance ≤ 10 Ω·cm. 6 Ω;

[0046] S6. Curing: Pre-dry with hot air at 80℃ for 2 minutes, then UV cured at 800-1000 mJ / cm². 2 800-1000mJ / cm 2 Rapid prototyping under energy conditions increases production speed to 120m / min.

[0047] The application of recycled materials and process integration in this preparation method reduces overall costs, meeting the cost reduction needs of the packaging industry.

[0048] The above-described embodiments are merely one implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A piezoelectric phase change six-ply moisture barrier corrugated paperboard, characterized by: Six layers are compounded from outside to inside: Antistatic piezoelectric layer (10): formed by electrospinning of lead zirconate titanate nanoparticles with polyvinylidene fluoride, thickness 0.05-0.1 mm, surface resistance <10 6 Ω; The moisture-proof functional layer (11) is compounded by polyurethane emulsion, fluorine-containing compound with carbon atom number ≥6 and hydroxypropyl chitosan, and has a thickness of 0.1-0.3 mm; The hydrophobic adhesive interface layer (12) is formed by mixing acrylic resin and TiO2 nanoparticles and then UV curing, has a thickness of 0.05-0.1 mm, and a contact angle ≥110°; The micro-fine honeycomb composite corrugated layer (13) is composed of G corrugation, F corrugation and V-shaped compression corrugation staggered arrangement, and the gap between the corrugated teeth is filled with nano-silica aerogel containing ≥30% of regenerated cellulose, and the water absorption rate is ≤1.5%; The phase change temperature control layer (14) is composed of paraffin / expanded graphite shaped phase change material, and has a paraffin adsorption rate ≥90%, a phase change enthalpy ≥180 J / g, and a thickness of 0.2-0.4 mm; Nano-reinforced substrate layer (15): made of 60% of coniferous wood pulp, 40% of Kenaf whole stem pulp and nano-CaC03 modified with red seaweed glue, basis weight 90 g / m 2 .

2. A piezoelectric phase change six-ply moisture barrier corrugated paperboard according to claim 1, characterized by: The zirconium titanate lead nanoparticles are 60-80 parts, the polyvinylidene fluoride is 20-40 parts; the mass ratio of the polyurethane emulsion to the fluorine-containing compound is 7:3; the hydroxypropyl chitosan is 5-8 parts; the acrylic resin is 50-75 parts, the particle size of the TiO2 nanoparticles is 20-50 nm, and 3-5 parts; the G corrugation has a corrugation height of 0.5-0.6 mm, the F corrugation has a corrugation height of 0.7-0.9 mm, and the V-shaped compression corrugation has a corrugation height of 1.8-2.0 mm; the red seaweed glue modified nano calcium carbonate is added in an amount of 8-12%.

3. A piezoelectric phase change six-ply moisture barrier corrugated paperboard according to claim 1, wherein: The antistatic piezoelectric layer (10) is subjected to polarization treatment, electric field intensity 15 kV / mm, time 30 min, piezoelectric constant d 33 ≥ 25 pC / N.

4. The piezoelectric phase change six-ply moisture barrier corrugated paperboard of claim 1, wherein: The phase change temperature control layer (14) has a pore size of 50-100 μm, and a phase change temperature interval of 5-35℃.

5. The piezoelectric phase change six-ply moisture barrier corrugated paperboard of claim 1, wherein: The TiO2 nanoparticles in the hydrophobic adhesive interface layer (12) generate hydroxyl radicals under ultraviolet light, and the formaldehyde degradation rate is ≥95%.

6. A piezoelectric phase change six-ply moisture barrier corrugated paperboard according to claim 1, wherein: Before the micro-fine honeycomb composite corrugated layer (13) is filled with aerogel, the corrugated tooth surface is subjected to reactive ion etching to form micro-nano level pits.

7. The piezoelectric phase change six-ply moisture barrier corrugated paperboard of claim 1, wherein: The total thickness of the six-layer structure is 3.2±0.3 mm, wherein the antistatic pressure layer (10) accounts for 3%, the moisture-proof functional layer (11) accounts for 7%, the hydrophobic adhesive interface layer (12) accounts for 5%, the micro-fine honeycomb composite corrugated layer (13) accounts for 55%, the phase change temperature control layer (14) accounts for 10%, and the nano-enhanced substrate layer (15) accounts for 20%.

8. The piezoelectric phase change six-ply moisture barrier corrugated paperboard of claim 1, wherein: The moisture-proof function layer (11) has a moisture permeation amount of ≤2.0 x 10 1 g / 24h-m 2 ·10 3 Pa at 25°C, a moisture permeation amount of ≥5.0 x 10 1 g / 24h-m 2 ·10 3 Pa at 35°C, and a moisture permeation amount of ≤1.5 x 10 1 g / 24h-m 2 ·10 3 Pa at 5°C.

9. A method of producing a corrugated paperboard according to any one of the preceding claims 1 to 8, characterized by: The method comprises the following steps: S1, substrate treatment: the surface of the nano-enhanced substrate layer (15) is subjected to low temperature plasma pretreatment, the power is 1.5 kW, the time is 30 s, and the temperature is 80℃; S2, phase change layer compounding: the molten paraffin / expanded graphite mixture is coated on the substrate layer, and hot pressing is performed at 80℃; S3, corrugated layer bonding: the hydrophobic adhesive interface layer (12) is coated on the phase change temperature control layer (14) by a slit extrusion coating head, The wet film thickness of the hydrophobic adhesive interface layer (12) is 50±5 μm, and the micro-fine honeycomb composite corrugated layer (13) is pressed; The coating precision of the hydrophobic adhesive interface layer (12) is controlled to be ±3 μm; S4, moisture-proof layer spraying: the moisture-proof functional layer (11) is coated on the outer surface of the corrugated layer by a micropore spraying device with a pore size of 50 μm, The spraying pressure is 0.3-0.5 MPa. ​ S5, piezoelectric layer covering: PZT / PVDF electrospinning solution, containing 0.5-1.0wt% carbon nanotubes, is covered on the moisture-proof functional layer (11), electrospinning voltage is 20kV, receiving distance is 15cm; 0.5-1.0wt% carbon nanotubes are added in the electrospinning solution, a three-dimensional conductive network is formed; S6, Curing: UV curing after 80°C hot air pre-drying for 2 min, energy 800-1000 mJ / cm 2 .

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