Manufacturing method of shimmering powder paper

Abstract

The invention discloses a shimmering powder paper manufacturing method which is characterized in that in the existing shimmering powder paper manufacturing process, an adhesive is not subjected to modification treatment, and nano-scale silicon dioxide particles are added into the adhesive, so that the mechanical anchoring effect and the interface bonding strength of the adhesive are remarkably enhanced; meanwhile, the stirring and coating processes are optimized, and the bonding uniformity between the shimmering powder and the base material paper and the stability of the overall structure are improved. Due to the addition of the nanoscale silicon dioxide particles, the cohesive force and the interface bonding capacity of the adhesive are improved, so that the adhesive force between the shimmering powder and the base material paper is remarkably enhanced, and the wear resistance and durability of the product are improved; the surface of the shimmering powder is uniformly coated with the enhanced composite adhesive through full stirring of the high-speed stirring device, the consistency and surface quality of a coating are guaranteed through the optimized coating process, the integrity and glossiness of the shimmering powder coating are guaranteed, and the shimmering powder paper is better than existing products in the visual effect and mechanical performance; and the ink is suitable for wider printing and decoration purposes.

Description

Technical Field

[0001] The present invention relates to the technical field of paper making, and specifically to a method for manufacturing glitter paper. Background Art

[0002] In recent years, glitter paper has been widely used in fields such as packaging, decoration, greeting cards, and art design due to its unique visual effects. Traditional glitter paper manufacturing processes usually involve directly spreading glitter on the surface of a substrate coated with glue, or forming a coating by simply mixing an adhesive with glitter. However, such methods have the following technical drawbacks: Poor glitter adhesion: The traditional adhesive does not uniformly coat the glitter, resulting in the glitter being easily shed during subsequent processing or use, affecting the durability of the product.

[0003] Insufficient coating strength: The mechanical properties of ordinary water-based adhesives after film formation are weak, and cracks are likely to appear during calendering or die-cutting, affecting the integrity and gloss of the glitter coating. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for manufacturing glitter paper, which solves the problems of poor glitter adhesion and insufficient coating strength of current glitter paper mentioned in the background art.

[0005] A method for manufacturing glitter paper includes uniformly dispersing nano-scale silica particles in a water-based adhesive to form a reinforced composite adhesive; mixing the reinforced composite adhesive with colored glitter in a set ratio and fully stirring through a high-speed stirring device so that the surface of the glitter is uniformly coated with the reinforced composite adhesive to form a glitter mixture; coating the glitter mixture on a base paper to form a glitter coating, and controlling the thickness and surface flatness of the glitter coating through a calendering process; finally, through drying and curing treatment, the glitter coating is firmly adhered to the base paper.

[0006] In one embodiment, the particle size of the nano-scale silica particles is 10 nm - 100 nm, and the dispersion concentration in the water-based adhesive is 5 wt% - 15 wt%.

[0007] In one embodiment, the reinforced composite adhesive further contains 0.1 - 5 wt% of carbon nanotubes, so that the surface resistivity of the coating ≤ 10 6 Ω / sq.

[0008] In one embodiment, the colored glitter is cellulose microspheres coated with a titanium dioxide nano-film on the surface, with a particle size of 50 μm - 500 μm.

[0009] In one embodiment, before applying the glitter mixture onto the base paper to form a glitter coating, the base paper is first subjected to micro-embossing treatment to form embossed recesses. The depth of the embossed recesses is 20 μm - 100 μm. After coating, the glitter mixture preferentially fills into the embossed recesses.

[0010] In one embodiment, after the base paper is subjected to micro-embossing treatment to form embossed recesses, a transparent barrier layer is first coated, and then the glitter coating is applied.

[0011] In one embodiment, the transparent barrier layer contains a fluorosurfactant, such that the contact angle of the transparent barrier layer at the raised portion of the base paper < 30°, and the contact angle at the recessed portion > 90°, forming a differential coverage.

[0012] In one embodiment, the transparent barrier layer further contains polyvinyl alcohol or nano-silica, with a thickness of 0.1 μm - 5 μm. The oxygen transmission rate of the transparent barrier layer < 10 cm³ / (m²·day·atm), and the water vapor transmission rate < 5 g / (m²·day).

[0013] In one embodiment, after applying the glitter coating, a UV-curable protective layer containing nano-aluminum oxide is sprayed onto the glitter coating, and the thickness of the protective layer is 5 μm - 50 μm.

[0014] In one embodiment, after the final drying and curing treatment to firmly attach the glitter coating to the base paper, a fluorosilicon polymer protective film with a thickness of 50 nm - 200 nm is vacuum-deposited on the surface of the glitter coating.

[0015] In the above method for manufacturing glitter paper, in the existing process of manufacturing glitter paper, the adhesive is not modified. However, in this application, nano-scale silica particles are added to the adhesive, significantly enhancing the mechanical anchoring effect and interfacial bonding strength of the adhesive. At the same time, the stirring and coating processes are optimized, improving the bonding uniformity between the glitter and the base paper and the overall structural stability. The addition of nano-scale silica particles increases the cohesive force and interfacial bonding ability of the adhesive, thus significantly enhancing the adhesion between the glitter and the base paper, improving the abrasion resistance and durability of the product. And through a high-speed stirring device, the glitter surface is uniformly coated with an enhanced composite adhesive. The optimized coating process ensures the consistency and surface quality of the coating, guaranteeing the integrity and gloss of the glitter coating, making the glitter paper superior to existing products in terms of visual effects and mechanical properties, and suitable for a wider range of high-end printing and decoration uses. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of a method for manufacturing glitter paper according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0018] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element present. In contrast, when an element is referred to as being "directly" connected to another element, there is no intermediate element.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0020] As Figure 1 shown, a method for manufacturing glitter paper includes S1. Uniformly disperse nano-scale silica particles in an aqueous adhesive to form a reinforced composite adhesive; the nano-scale silica particles are fumed SiO2 modified by a silane coupling agent, the particle size of the nano-scale silica particles is 10nm - 100nm, preferably 20nm - 50nm, and the dispersion concentration in the aqueous adhesive is 5wt% - 15wt%. The nano-scale particles can fill the gaps between the adhesive molecular chains and improve the density; First, prepare a SiO2 premixed slurry containing a dispersant by ultrasonic-assisted dispersion, and then shear-mix it with the aqueous adhesive at a rotation speed of 8000rpm - 12000rpm for 30min - 60min; adding 5wt% nano-SiO2 can significantly improve the tensile strength, wear resistance, and adhesion of the composite adhesive; S2. Mix the enhanced composite adhesive and colored glitter in a set ratio, and fully stir them with a high-speed stirring device so that the surface of the glitter is evenly coated with the enhanced composite adhesive to form a glitter mixture; the surface of the colored glitter is treated with a titanate coupling agent, and the mass ratio of the colored glitter to the enhanced composite adhesive is 1:5 to 1:15; the high-speed stirring device is equipped with a serrated rotor and a vacuum system, and the system pressure is maintained at -0.06 ± 0.01 MPa during stirring; stir until the free adhesive content in the mixture ≤ 2.5 wt%, and the coefficient of variation of the coating layer thickness on the surface of the glitter ≤ 10%; the adhesive enhanced by nano-SiO2 can form a continuous film. Compared with ordinary adhesives: the edge coverage rate of the glitter increases from 65% to 92%; the peel strength is increased by 2.3 times. S3. Coat the glitter mixture on the base paper to form a glitter coating, and control the thickness and surface flatness of the glitter coating through a calendering process; the calendering process uses a combination of an elastic roller and a steel roller, where the hardness of the elastic roller is 80 ± 5 Shore A, the surface temperature of the steel roller is 135°C ± 5°C, after coating, preheat at 80°C - 100°C for 30 seconds - 90 seconds first, and then perform calendering, and the calendering line pressure is 80 kg / cm - 120 kg / cm. S4. Finally, perform a drying and curing treatment to firmly attach the glitter coating to the base paper. The drying and curing is divided into three stages: a) Initial drying at 65 ± 5°C for 2 - 4 min, humidity 30 - 50%; b) Gel curing at 105 ± 3°C for 1 - 2 min; c) Final curing at 140 ± 5°C for 30 - 60 seconds.

[0021] In this way, for a method of making glitter paper, in the existing process of making glitter paper, the adhesive is not modified. In this application, nano-scale silica particles are added to the adhesive, significantly enhancing the mechanical anchoring effect and interfacial bonding strength of the adhesive; at the same time, the stirring and coating processes are optimized, improving the bonding uniformity and overall structural stability between the glitter and the base paper. The addition of nano-scale silica particles increases the cohesive force and interfacial bonding ability of the adhesive, thus significantly enhancing the adhesion between the glitter and the base paper, improving the wear resistance and durability of the product; and fully stirring with a high-speed stirring device so that the surface of the glitter is evenly coated with the enhanced composite adhesive, and the optimized coating process ensures the consistency and surface quality of the coating, ensuring the integrity and gloss of the glitter coating, making the glitter paper superior to existing products in terms of visual effects and mechanical properties, and applicable to a wider range of high-end printing and decoration uses.

[0022] In one of the embodiments, the enhanced composite adhesive further contains 0.1 - 5 wt% of carbon nanotubes, so that the surface resistivity of the coating ≤ 10 6 Ω / sq.

[0023] In this way, carbon nanotubes belong to conductive nanomaterials. Adding carbon nanotubes to the enhanced composite adhesive enables the glitter paper to have antistatic or circuit printing functions.

[0024] In one of the embodiments, the colored glitter is cellulose microspheres coated with a titanium dioxide nanomembrane on the surface, with a particle size of 50μm - 500μm.

[0025] In this way, the refractive index of titanium dioxide TiO2 is as high as 2.4 - 2.7 (for ordinary glitter it is 1.5 - 1.7). The flash intensity of the glitter is enhanced through the interference effect. For example, coating a 50nm TiO2 film can increase the specular reflectivity of the glitter by 40% - 60%. The iridescent effect is achieved by controlling the thickness of the TiO2 film (80 - 200nm). When the film thickness is 150nm, a blue - gold color - changing effect is presented.

[0026] In one of the embodiments, before coating the glitter mixture on the base paper to form a glitter coating, the base paper is first subjected to micron - level embossing treatment to form embossed recesses. The depth of the embossed recesses is 20μm - 100μm. After coating, the glitter mixture preferentially embeds into the embossed recesses.

[0027] In this way, the geometric structure of the embossed recesses increases the contact area of the glitter (3 - 5 times more than that of a flat base material). After testing, the peel strength: is increased from 3.2N / 25mm to 7.8N / 25mm. The embossed lines serve as physical flow channels, avoiding the aggregation of glitter during coating, and the coefficient of variation (CV) value of the distribution uniformity is improved from 15% to less than 5%.

[0028] In one of the embodiments, after the base paper is subjected to micron - level embossing treatment to form embossed recesses, a transparent barrier layer is first coated, and then the glitter coating is applied. The transparent barrier layer also contains polyvinyl alcohol or nano - silica, with a thickness of 0.1μm - 5μm. The oxygen transmission rate of the transparent barrier layer < 10cm³ / (m²·day·atm), and the water vapor transmission rate < 5g / (m²·day).

[0029] In this way, the transparent barrier layer (such as a PVOH, nano - silica composite coating) can prevent the glitter from falling off due to friction or bending during subsequent processing or use, improving the durability of the product. For example, adding a 1μm - thick PVOH barrier layer can reduce the glitter shedding rate by more than 60%.

[0030] The transparent barrier layer can also block environmental media such as oxygen and water vapor to prevent the metal layer of the glitter from oxidizing and discoloring (especially important for aluminum powder glitter). For example, a barrier layer with an oxygen permeability of less than 5cm³ / (m²·day) can extend the color stability of the glitter by 2-3 times. In addition, by selecting a barrier layer material with a refractive index between the substrate (~1.5) and the glitter (metal powder ~1.7) (such as acrylic resin 1.49), the interfacial light scattering can be reduced, and the glossiness of the glitter can be increased by 20%-30%.

[0031] In one embodiment, the transparent barrier layer contains a fluorinated surfactant, so that the contact angle of the transparent barrier layer at the protrusions of the substrate paper is less than 30°, and the contact angle at the concave part is greater than 90°, thereby forming differentiated coverage.

[0032] Thus, according to such a structural arrangement, the transparent barrier layer spontaneously avoids the grooved concave portions, leaving space for the glitter powder to fill.

[0033] In one embodiment, after the glitter coating is applied, a UV-curable protective layer containing nano-aluminum oxide is sprayed on the glitter coating, and the thickness of the protective layer is 5 μm-50 μm.

[0034] In this way, nano Al2O3 (Mohs hardness 9) increases the pencil hardness of the glitter coating from 2H to 6H, and the refractive index of Al2O3 is 1.76≈the refractive index of glitter (1.7-1.9), which reduces interface scattering and increases the glossiness of the glitter paper (Gs60°) by 15%-20%.

[0035] In one of the embodiments, after the final drying and curing treatment to make the glitter coating firmly adhere to the substrate paper, a 50nm-200nm thick fluorosilicone polymer protective film is vacuum plated on the surface of the glitter coating.

[0036] Fluorosilicone polymer characteristics: low surface energy (10-15mN / m): contains -CF3 / -CF2- groups, contact angle>110°; Molecular chain flexibility: Si-O bond energy 452kJ / mol, giving high elasticity (elongation at break>200%); Chemical inertness: acid and alkali resistance (pH1-14), UV resistance (QUV aging 3000h ΔE<1); Advantages of vacuum coating process: Molecular level precision: Plasma enhanced chemical vapor deposition (PECVD) controls the film thickness to ±5nm; Low temperature film formation: Substrate temperature <80℃, avoiding thermal damage to glitter; Three-dimensional coating: Even for complex textures, the coverage of glitter is >99% (SEM verification). Friction resistance is significantly increased. Visible light transmittance >95%, haze increase <0.5%, and mirror reflectivity retention rate >98%.

[0037] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for making glitter paper, characterized in that: including Uniformly disperse nanoscale silica particles in an aqueous adhesive to form a reinforced composite adhesive; Mix the reinforced composite adhesive with colored glitter in a set ratio and fully stir through a high-speed stirring device so that the surface of the glitter is uniformly coated with the reinforced composite adhesive to form a glitter mixture; Coat the glitter mixture on a base paper to form a glitter coating, and control the thickness and surface flatness of the glitter coating through a calendering process; Finally, through drying and curing treatment, make the glitter coating firmly adhere to the base paper.

2. The method for manufacturing glitter paper according to claim 1, characterized in that: The particle size of the nanoscale silica particles is 10nm - 100nm, and the dispersion concentration in the aqueous adhesive is 5 wt% - 15wt%.

3. The method for manufacturing glitter paper according to claim 1, characterized in that: The enhanced composite binder also contains 0.1-5 wt% of carbon nanotubes, such that the surface resistivity of the coating ≤ 10 6 Ω / sq.

4. The method for manufacturing glitter paper according to claim 1, wherein: The colored glitter is a cellulose microsphere with a titanium dioxide nanofilm coated on the surface, and the particle size is 50μm - 500μm.

5. A method for manufacturing glitter paper according to claim 1, characterized in that: Before coating the glitter mixture on the base paper to form a glitter coating, first perform a micron-level embossing treatment on the base paper to form embossed recesses, the depth of the embossed recesses is 20μm - 100μm, and after coating, the glitter mixture preferentially embeds into the embossed recesses.

6. A method for manufacturing glitter paper according to claim 5, characterized in that: After performing the micron-level embossing treatment on the base paper to form embossed recesses, first coat a transparent barrier layer, and then coat the glitter coating.

7. A method for manufacturing glitter paper according to claim 6, characterized in that: The transparent barrier layer contains a fluorosurfactant, so that the contact angle of the transparent barrier layer at the raised part of the base paper < 30°, and the contact angle at the recessed part > 90°, forming a differential coverage.

8. A method for manufacturing glitter paper according to claim 7, characterized in that: The transparent barrier layer also contains polyvinyl alcohol or nanosilica, and the thickness is 0.1μm - 5μm. The oxygen transmission rate of the transparent barrier layer < 10 cm³ / (m²·day·atm), and the water vapor transmission rate < 5 g / (m²·day).

9. The method for manufacturing glitter paper according to claim 8, characterized in that: After coating the glitter coating, spray a UV-curable protective layer containing nanoaluminum oxide on the glitter coating, and the thickness of the protective layer is 5μm - 50μm.

10. A method for manufacturing glitter paper according to claim 1, characterized in that: After the final drying and curing treatment to make the glitter coating firmly adhere to the base paper, vacuum deposit a 50nm - 200nm thick fluorosilicon polymer protective film on the surface of the glitter coating.

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