Preparation method of locally-enhanced 3D foaming paper cup and paper bowl

Abstract

The invention discloses a preparation method of a locally-enhanced 3D foamed paper cup and paper bowl, and relates to the technical field of paper product preparation. The method comprises the following steps: applying a layer of spraying film or coating on one side or two sides of paper to form a waterproof and oil-proof protective layer; after a spraying film or a coating is formed in the paper cup or the paper bowl, one or more layers of polystyrene foam are evenly smeared on a specific area outside paper through the silk-screen printing technology, and a preset pattern is formed; the depth and the texture of the pattern are increased by superposing the polystyrene foam layer; printing colored patterns on the opaque polystyrene foam layer or under the transparent polystyrene foam layer by using an offset printing technology; processing the treated paper into a paper cup or a paper bowl according to a preset mold shape; the molded paper product is placed in a temperature-controllable heating device, the polystyrene foam is expanded through heating, so that a 3D effect is formed on the outer surface of the paper product, and high-quality production and excellent performance of the locally-enhanced 3D foaming paper cups and paper bowls are ensured through the steps.

Description

Technical Field

[0001] The invention belongs to the technical field of paper product preparation, and in particular relates to a method for preparing a locally enhanced 3D foamed paper cup or paper bowl. Background Art

[0002] Paper cups and paper bowls are indispensable products in people's daily lives. They are widely used for their convenience, recyclability and environmental friendliness. However, the printed surface of paper cups and paper bowls is generally flat. When they are filled with hot and ice liquids and food, they have no temperature barrier effect. They are easy to burn and the user experience they bring to consumers is not as good as that of rubber, ceramic, metal and other materials. The double-layer paper cups or folding paper cups on the market or those used in cup sleeves have complex production processes, high costs, and lack of ornamental value. Paper cups with a coating layer on one side and a foaming agent on the other side have an overall foamed outer layer. Because the coating layer is relatively thin, the foamed layer is also relatively thin. The high-temperature or low-temperature barrier effect is relatively poor and there is no three-dimensional effect.

[0003] To this end, we provide a method for preparing a locally enhanced 3D foamed paper cup and paper bowl to solve the above-mentioned problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0005] The present invention is a method for preparing a locally enhanced 3D foamed paper cup or paper bowl, comprising the following steps:

[0006] S100, applying a layer of laminating film or coating to one side or both sides of the paper to form a waterproof and oil-proof protective layer;

[0007] S200, after forming a coating layer inside the paper cup or paper bowl, uniformly apply one or more layers of foam glue on a specific area outside the paper using a screen printing technique to form a predetermined pattern;

[0008] S300, optionally, repeating step S200 to increase the depth and texture of the pattern by stacking a foam glue layer;

[0009] S400, using offset printing technology on the opaque foamed adhesive layer formed in step S300 or on the transparent

[0010] Print colorful patterns under the foam to enhance the visual effect;

[0011] S500, processing the processed paper into a paper cup or paper bowl according to a preset mold shape;

[0012] S600, placing the formed paper product in a temperature-controllable heating device, and expanding the foam by heating, thereby forming a 3D stereoscopic effect on the outer surface of the paper product.

[0013] The present invention is further configured such that the coating material in step S100 is polyethylene (PE), polypropylene (PP), polylactic acid (PLA) or a combination and coating thereof, and the thickness of the coating layer is 5 μm to 30 μm, preferably 15 μm to 25 μm.

[0014] The present invention is further configured that the foam glue in steps S200 and S300 is an environmentally friendly water-based foam glue, and the dry thickness of the foam glue is 0.1 mm to 1 mm;

[0015] The viscosity of the foam glue used in the screen printing process in step S200 ranges from 1000 cps to 5000 cps.

[0016] The present invention is further configured such that the ink used for offset printing in step S400 is UV curable ink or water-based ink, the ink contains a photoinitiator or a thermosetting agent, and the dry thickness of the ink is 5 μm to 15 μm.

[0017] The present invention is further configured such that the heating device in step S600 is provided with a temperature control unit, which can accurately control the heating temperature within the range of 100°C to 180°C, and the heating time is controlled between 30 seconds and 5 minutes, and the heating device also includes a cooling system.

[0018] The present invention is further configured such that an anti-permeability isolation layer is provided between the inner coating layer and the outer foam rubber layer, and the isolation layer material is polyethylene (PE) or polypropylene (PP) and has a thickness of 5 μm to 15 μm.

[0019] The present invention is further configured such that the bottom and side of the paper cup or paper bowl are tightly connected by a hot pressing or cold pressing process, the connection between the bottom and the side adopts seamless welding technology, the welding width is 2mm to 10mm, and the top edge curling width of the paper cup or paper bowl is 5mm to 15mm.

[0020] The present invention is further configured that the paper material is kraft paper, white cardboard, recycled paper or composite paper, and the grammage of the paper is 150g / m 2 Up to 350g / m 2 , preferably 200g / m 2 Up to 300g / m 2 .

[0021] The present invention is further configured such that the height of the 3D foaming in step S600 is between 0.1 mm and 5 mm.

[0022] A method for preparing a locally enhanced 3D foamed paper cup or paper bowl also includes spraying or coating a layer of waterproof and breathable film on the outside of the paper cup or paper bowl, wherein the material of the waterproof and breathable film is fluorocarbon resin, siloxane or a combination thereof, and the film thickness is 5 μm to 20 μm.

[0023] The present invention has the following beneficial effects:

[0024] 1. The present invention forms an effective waterproof and oil-proof protective layer by applying a layer of laminating or coating material, such as polyethylene (PE), polypropylene (PP), or polylactic acid (PLA), on one or both sides of the paper, so that the paper cups and paper bowls will not leak when containing liquid or oily foods, thereby improving the safety and hygiene of the products. An anti-penetration isolation layer is provided between the inner laminating layer and the outer foaming layer, thereby further enhancing the waterproof and oil-proof performance of the product and preventing the foaming layer from penetrating into the inner laminating layer and affecting the product performance.

[0025] 2. The present invention forms a 3D effect by evenly applying one or more layers of foam glue on a specific area outside the paper and expanding it during the heating process, which not only improves the visual effect of the product, but also increases the texture when touched, allowing users to feel more pleasure and comfort during use. Color patterns are printed on the foam glue layer using offset printing technology, which improves the aesthetics and artistic sense of the product. The use of UV curing ink or water-based ink ensures the vividness and durability of the pattern.

[0026] 3. The present invention adopts environmentally friendly water-based foaming glue, which is non-toxic, harmless, and easily degradable, meets environmental protection requirements, and reduces the impact on the environment. Recycled paper is selected as the raw material, which further reduces the resource consumption and environmental pollution in the production process. A layer of waterproof and breathable film is sprayed or coated on the outside of the paper cup or paper bowl. The material is fluorocarbon resin, siloxane or a combination thereof, which not only improves the waterproof performance, but also maintains the air permeability, thereby extending the service life of the product.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 The present invention is a flow chart for preparing the locally enhanced 3D foamed paper cups and paper bowls. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example

[0032] See also Figure 1 The present invention is a method for preparing a locally enhanced 3D foamed paper cup or paper bowl, comprising the following steps:

[0033] S100, coating treatment: Choose kraft paper, white cardboard, recycled paper or composite paper to ensure it has good strength and durability. The paper weight should be 150g / m 2 Up to 350g / m 2 Between, preferably 200g / m 2 Up to 300g / m 2 The weight of the paper can be verified by weighing or instrument measurement to ensure that the surface of the paper is flat, free of stains and tears. If necessary, pre-treatment such as dust removal and polishing can be performed;

[0034] Choose polyethylene (PE), polypropylene (PP), polylactic acid (PLA) or their combination and other coatings. These materials have good waterproof and oil-proof properties. The thickness of the coating layer should be between 5μm and 30μm, preferably 15μm to 25μm. The thickness can be controlled by adjusting the speed, pressure and coating amount of the coating machine. Use a thickness gauge to regularly check the thickness of the coating layer to ensure that it is uniform.

[0035] Use a professional laminating machine to ensure that the equipment is clean, dust-free and pollution-free. Feed the paper into the laminating machine and adjust the laminating speed and pressure to ensure that the laminating layer evenly covers one or both sides of the paper. Check the paper after laminating to ensure that there are no defects such as bubbles, cracks, wrinkles, etc.

[0036] Use efficient drying equipment, such as infrared dryer or hot air dryer, to feed the coated paper into the drying equipment, set appropriate temperature and time to ensure that the coated layer is completely dry. The dried paper should be smooth and not damp, which can be confirmed by hand or instrument detection.

[0037] S200, Foam printing: Choose environmentally friendly water-based foam, ensure that it is non-toxic, harmless and easily degradable. The viscosity of the foam should be between 1000cps and 5000cps. The viscosity can be adjusted by adding diluent or thickener. Use a viscometer to regularly test the viscosity of the foam to ensure that it is within the appropriate range.

[0038] Use a professional screen printing machine to ensure that the screen is clean, dust-free and pollution-free. Apply the foam glue evenly on the screen. Adjust the printing speed and pressure to ensure that the foam glue is evenly distributed on the specific area outside the paper. According to the design requirements, make a suitable screen to ensure the clarity and accuracy of the pattern. The paper after printing should have no missing prints, no blur, and no excess colloid, which can be confirmed by visual inspection or instrument detection;

[0039] Use efficient drying equipment, such as infrared dryer or hot air dryer, feed the paper printed with foam glue into the drying equipment, set appropriate temperature and time to ensure that the foam glue is completely dried. The thickness of the foam glue layer after drying should be controlled between 0.1mm and 1mm, which can be confirmed by thickness gauge.

[0040] S300, superimpose foam glue layer: If you need to increase the depth and texture of the pattern, you can repeat the S200 step and print the foam glue again; according to the design requirements, control the number of foam glue layers, usually not more than 3 layers, to avoid deformation or cracking caused by excessive thickness. Appropriate drying treatment is required after each printing to ensure that each layer of foam glue can be fully dried and fixed.

[0041] S400, color pattern printing: Choose UV curing ink or water-based ink to ensure good adhesion and durability. The ink should contain photoinitiator or thermosetting agent to improve the curing speed and adhesion of the ink. Use viscometer and densitometer to regularly test the viscosity and density of the ink to ensure that it is within the appropriate range.

[0042] Use a professional offset printing machine to ensure that the printing plate is clean, dust-free and pollution-free, apply the ink evenly on the printing plate, adjust the printing speed and pressure, ensure that the ink is evenly distributed on the foam layer, make a suitable printing plate according to the design requirements, ensure the clarity and accuracy of the pattern, and the paper after printing should have no missing prints, no blur, and no excess ink, which can be confirmed by visual inspection or instrument detection;

[0043] If UV curing ink is used, feed the printed paper into the UV curing equipment, set the appropriate light intensity and time to ensure that the ink is completely cured. If water-based ink is used, feed the printed paper into the hot air drying equipment, set the appropriate temperature and time to ensure that the ink is completely dry. The thickness of the ink layer after drying should be controlled between 5μm and 15μm, which can be confirmed by a thickness gauge.

[0044] S500, Forming processing: Make appropriate molds according to the design drawings to ensure the accuracy and durability of the molds. The mold materials should be high-strength, high-temperature resistant metals or alloys. Use a three-coordinate measuring instrument to regularly check the size and accuracy of the molds to ensure that they meet the requirements;

[0045] Use professional forming equipment, such as punching machines or die-cutting machines, to ensure that the equipment is clean, dust-free and pollution-free. Feed the paper that has been treated as above into the forming equipment, and punch or die-cut it according to the preset mold shape to make the prototype of paper cups or paper bowls. The formed paper products should be free of burrs, cracks and deformations, which can be confirmed by visual inspection or instrument detection.

[0046] Use hot pressing or cold pressing technology to ensure that the bottom and sides of the paper cup or paper bowl are tightly connected. Use seamless welding technology to ensure that the welding width is 2mm to 10mm. The welding part should be firm and without leaks. The paper products after welding should be free of bubbles, cracks, and looseness, which can be confirmed by tensile test or water pressure test;

[0047] Use professional curling equipment to ensure that the equipment is clean, dust-free and pollution-free, and curl the top edge of the paper cup or paper bowl. The curling width is 5mm to 15mm. Ensure that the edge is flat and smooth. The paper product after curling should be free of burrs, cracks and deformation, which can be confirmed by visual inspection or instrument detection.

[0048] S600, heating and foaming: use a heating device with a temperature control unit to ensure that the heating temperature can be accurately controlled, set the heating temperature in the range of 100°C to 180°C, select a suitable temperature according to the characteristics of the foaming glue, set the heating time between 30 seconds and 5 minutes, and select a suitable time according to the characteristics of the foaming glue;

[0049] Place the formed paper product in a heating device and start the heating process to expand the foam layer to form a 3D effect. The heated paper product should not be burnt, cracked or deformed, which can be confirmed by visual inspection or instrument detection;

[0050] Use a heating device with a cooling system to ensure that the cooling process is slow. After heating is completed, start the cooling system immediately to gradually cool the paper product to ensure that the foaming structure is stable and not deformed. The cooled paper product should have no condensation, deformation, or cracking, which can be confirmed by visual inspection or instrument detection.

[0051] The anti-permeability isolation layer should be made of polyethylene (PE) or polypropylene (PP) to ensure that it has good anti-permeability performance. The thickness of the isolation layer should be between 5μm and 15μm. The thickness can be controlled by adjusting the coating speed and pressure. Use a thickness gauge to regularly check the thickness of the isolation layer to ensure that it is uniform.

[0052] The waterproof and breathable membrane should be made of fluorocarbon resin, silicone or a combination thereof to ensure that it has good waterproof and breathable properties. The thickness of the waterproof and breathable membrane should be between 5μm and 20μm. The thickness can be controlled by adjusting the spraying or coating speed and pressure. A thickness gauge and a waterproof and breathable tester should be used to regularly test the thickness and performance of the waterproof and breathable membrane to ensure that it meets the requirements.

[0053] The above steps ensure the high-quality production and excellent performance of locally enhanced 3D foamed paper cups and paper bowls. Each step needs to be strictly controlled according to parameters to ensure the quality and functionality of the final product.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0055] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a locally enhanced 3D foamed paper cup or paper bowl, characterized in that: The following steps are involved: S100, applying a layer of laminating film or coating to one side or both sides of the paper to form a waterproof and oil-proof protective layer; S200, after forming a coating layer inside the paper cup or paper bowl, uniformly apply one or more layers of foam glue on a specific area outside the paper using a screen printing technique to form a predetermined pattern; S300, optionally, repeating step S200 to increase the depth and texture of the pattern by stacking a foam glue layer; S400, using offset printing technology to print a color pattern on the opaque foam glue layer or under the transparent foam glue formed in step S300 to enhance the visual effect; S500, processing the processed paper into a paper cup or paper bowl according to a preset mold shape; S600, placing the formed paper product in a temperature-controllable heating device, and expanding the foam by heating, thereby forming a 3D stereoscopic effect on the outer surface of the paper product.

2. The method for preparing the locally enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The coating material in step S100 is polyethylene (PE), polypropylene (PP), polylactic acid (PLA) or a combination thereof and various coatings. The thickness of the coating layer or coating is 5 μm to 30 μm, preferably 15 μm to 25 μm.

3. The method for preparing the locally enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The foam glue in steps S200 and S300 is an environmentally friendly water-based foam glue, and the dry thickness of the foam glue is 0.1 mm to 1 mm; The viscosity of the foam glue used in the screen printing process in step S200 ranges from 1000 cps to 5000 cps.

4. The method for preparing the partially enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The ink used for offset printing in step S400 is UV curable ink or water-based ink, the ink contains a photoinitiator or a thermosetting agent, and the dry thickness of the ink is 5 μm to 15 μm.

5. The method for preparing the locally enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The heating device in step S600 is provided with a temperature control unit, which can accurately control the heating temperature within the range of 100° C. to 180° C., and the heating time is controlled between 30 seconds and 5 minutes. The heating device also includes a cooling system.

6. The method for preparing the partially enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: An anti-penetration isolation layer is arranged between the inner coating layer and the outer foam rubber layer. The isolation layer material is polyethylene (PE) or polypropylene (PP) and has a thickness of 5 μm to 15 μm.

7. The method for preparing the partially enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The bottom and side of the paper cup or paper bowl are tightly connected by hot pressing or cold pressing process, the connection between the bottom and the side adopts seamless welding technology, the welding width is 2mm to 10mm, and the top edge curling width of the paper cup or paper bowl is 5mm to 15mm.

8. The method for preparing the partially enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The paper material is kraft paper, white cardboard, recycled paper or composite paper, and the weight of the paper is 150g / m 2 Up to 350g / m 2 , preferably 200g / m 2 Up to 300g / m 2 .

9. The method for preparing the partially enhanced 3D foamed paper cup and paper bowl according to claim 1, characterized in that: The 3D foaming height in step S600 is between 0.1 mm and 5 mm.

10. The method for preparing the partially enhanced 3D foamed paper cup or paper bowl according to claim 1, characterized in that: The method further comprises spraying or coating a layer of waterproof and breathable film on the outside of the paper cup or paper bowl. The material of the waterproof and breathable film is fluorocarbon resin, siloxane or a combination thereof, and the film thickness is 5 μm to 20 μm.

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