Composite paper can production method and composite paper can

Abstract

The invention discloses a composite paper can production method and a composite paper can, and belongs to the technical field of food packaging, the composite paper can comprises a damp-proof layer, a blocking layer, a supporting layer and a printing layer which are sequentially arranged from inside to outside, and the composite paper can production method comprises the following steps that the supporting layer is straightened and conveyed; coating a rice paste adhesive on one side surface of the supporting layer to form a first adhesive layer; conveying a barrier layer to the upper part of the first bonding layer and carrying out hot-pressing compounding to form a composite material layer; winding and shaping the composite material layer to form a cylinder body; processing a flowing moisture-proof object on the inner wall of the barrel, and drying to form a moisture-proof layer; conveying the printing layer to the outside of the cylinder body and bonding to form a paper tube; and cutting the paper tube to obtain a primary paper can. The composite paper can has the beneficial effects that pollution gas emission in the composite paper can production process is reduced, and the degradability of the composite paper can is improved.

Description

Technical Field

[0001] The present application relates to a method for producing a composite paper can and a composite paper can, belonging to the technical field of food packaging. Background Art

[0002] A composite paper can is a packaging container made by laminating paper with other materials, mainly used for food packaging. A composite paper can usually consists of four layers, namely a moisture-proof layer, a barrier layer, a support layer, and a printing layer from the inside out. Among them, the moisture-proof layer uses polyethylene or polypropylene film for moisture-proof and sealing of food; the barrier layer uses aluminum foil or aluminized film for blocking oxygen and light; the support layer uses kraft paper or white cardboard to improve the structural strength of the composite paper can; the printing layer uses various papers with patterns printed on the surface.

[0003] Due to the rapid development of the food industry, the demand for the number of composite paper cans is extremely large. And during the production process of composite paper cans, adjacent layers need to be bonded by applying glue. However, solvent-based glue will emit VOCs during the curing process, which not only causes environmental pollution during production. Summary of the Invention

[0004] A first object of the present application is to provide a method for producing a composite paper can, aiming to solve the problem of large pollution during the production process of composite paper cans in the prior art.

[0005] The technical problems to be solved by the present application are achieved by adopting the following technical solutions: A method for producing a composite paper can includes the following steps: Straighten and convey the support layer; Apply rice paste adhesive on one side of the support layer to form a first adhesive layer; Convey the barrier layer above the first adhesive layer and perform hot pressing and lamination to form a composite material layer; Wind and shape the composite material layer to form a cylinder; Process a flowing moisture-proof material on the inner wall of the cylinder, and after drying, form a moisture-proof layer; Convey the printing layer to the outside of the cylinder and bond it to form a paper tube.

[0006] Through the foregoing technical solutions, rice paste adhesive is used instead of solvent-based glue, thus avoiding the problem of VOC emissions during the production process. In addition, the cost of rice paste adhesive is lower than that of solvent-based glue, there are no pollutant emissions during the production process, and rice paste adhesive can be completely degraded. Whether it is the pre-production or the post-treatment, it is environmentally friendly and pollution-free, meeting the current manufacturing principle of building an environmentally friendly production.

[0007] In this application, a flowing moisture-proof material is used for drying to form a moisture-proof layer, replacing the polyethylene or polypropylene film in the prior art, further reducing the use of glue in the production process of composite paper cans, thereby being more environmentally friendly and reducing production costs. At the same time, in this application, the step of first laminating the moisture-proof layer, barrier layer, and support layer and then winding in the prior art is changed to first laminating the barrier layer and support layer, and then processing the moisture-proof layer after winding is completed; thus, the conveying route for pulling the moisture-proof layer is reduced, shortening the processing production line and the floor area of the equipment.

[0008] As an alternative embodiment of a method for producing composite paper cans, the rice paste adhesive comprises cooked glutinous rice and water, and the weight ratio of cooked glutinous rice to water is 1:(1.2 - 2).

[0009] Through the foregoing technical solution, the rice paste adhesive made of cooked glutinous rice will be more delicate, thereby improving the bonding strength after curing. Moreover, it is easier to mix cooked glutinous rice and water, reducing the energy consumption during the mixing process. Because producing the rice paste adhesive with cooked glutinous rice only requires steaming and mixing, while directly mixing raw glutinous rice requires crushing the raw glutinous rice to a corresponding particle fineness before steaming, which has higher requirements for the cutter head and energy, and the particle size of the produced rice paste adhesive is not good, and the viscosity is inferior to that of the rice paste adhesive produced with cooked glutinous rice.

[0010] As an alternative embodiment of a method for producing composite paper cans, the rice paste adhesive includes plant ash.

[0011] Through the foregoing technical solution, plant ash is the ash produced after plant combustion, which has the effect of sterilization and disinfection, and can perform pre-sterilization treatment on the surface of the support layer, thereby improving the safety of the composite paper can itself. In addition, the particle size of plant ash is extremely fine, facilitating the mixing with glutinous rice paste, and plant ash is convenient to obtain and low in cost, and can be obtained from the burned-out materials such as fruit charcoal.

[0012] As an alternative embodiment of a method for producing composite paper cans, the rice paste adhesive is prepared by the following method: Take glutinous rice and water, and obtain cooked glutinous rice after steaming; Take the corresponding weight portions of cooked glutinous rice and water and mix them evenly until they are broken and fused and in a state of not separating when standing, to obtain glutinous rice paste; Take the corresponding weight portion of plant ash, add it to the glutinous rice paste and mix evenly to obtain the rice paste adhesive, and keep the rice paste adhesive at 30 - 45 degrees Celsius for use.

[0013] Through the foregoing technical solution, the rice paste adhesive obtained has good fluidity and adhesiveness, and has a long shelf life under the sterilization effect of plant ash, which is convenient for transportation and long-term use. If the rice paste adhesive is made on-site and kept warm at 30-45 °C to have good fluidity and uniformity, it can be homogenized with each other after being applied to the surface of the support layer, thereby improving the surface flatness of the first adhesive layer.

[0014] As an alternative of a composite paper can production method, after applying the rice paste adhesive to one side of the support layer, sizing is performed on the first adhesive layer to make the thickness of the first adhesive layer not exceed 0.35 mm.

[0015] Through the foregoing technical solution, sizing the first adhesive layer can ensure that the thickness of the first adhesive layer does not exceed the required thickness for adhesion, which can not only improve the utilization rate of the rice paste adhesive, but also ensure the adhesion thickness of the first adhesive layer, and avoid glue overflow at the edge of the support layer during the later composite process. The rice paste adhesive obtained by sizing needs to be re-mixed with water to the appropriate fluidity for recycling.

[0016] As an alternative of a composite paper can production method, when hot-pressing and compounding the main partition layer and the support layer, negative pressure is applied to the first adhesive layer to extract water vapor, and the water vapor is recycled.

[0017] Through the foregoing technical solution, in order to ensure the fluidity of the rice paste adhesive, the water content in the rice paste adhesive is relatively high. Using negative pressure to extract the water vapor generated by heating can achieve rapid drying and curing of the rice paste adhesive, thereby improving production efficiency. At the same time, the extracted water vapor has heat and humidity, and can improve the resource utilization rate after recycling, further improving the environmental protection level of the entire production line.

[0018] As an alternative of a composite paper can production method, when winding and shaping the composite material layer, a spiral winding method is adopted, and the joint is fixed with a UV curing agent glue.

[0019] Through the foregoing technical solution, the UV curing agent glue can be rapidly cured by ultraviolet irradiation, which can accelerate the winding and shaping of the composite material layer to form a cylinder, improving production efficiency. And because the price of the UV curing agent glue is relatively high, it is only used at the winding joint position in this application, and the dosage is very small, which can reduce the cost of the composite paper can.

[0020] As an alternative of a composite paper can production method, when processing a flowable moisture-proof material on the inner wall of the cylinder, the flowable moisture-proof material is the rice paste adhesive; The rice paste adhesive is applied to the inner wall of the cylinder, and the cylinder is rotated to apply centrifugal force to the herder adhesive to make it uniform.

[0021] Through the foregoing technical solution, the rice paste adhesive produced using starch as the raw material has been used since ancient times in China for pasting window papers and building walls and buildings. Therefore, its cured structural strength and durability are very good, and it also has strong moisture-proof and corrosion-resistant effects. In this application, cooked glutinous rice is used as the main source of starch for the rice paste adhesive, so that the surface of the rice paste curing agent is smoother and flatter after curing. At the same time, this application uses centrifugal force to form a uniform and continuous layer structure of the rice paste adhesive on the inner wall of the cylinder, which not only reduces the production cost but also achieves a good moisture-proof isolation effect. In addition, the raw materials of the rice paste adhesive are safe and environmentally friendly, which can ensure the safety of the food inside the composite paper can; at the same time, the rice paste adhesive can be completely degraded without causing secondary pollution.

[0022] As an alternative solution of a composite paper can production method, when processing a flowing moisture-proof material on the inner wall of the cylinder, the flowing moisture-proof material is a beeswax ethanol solvent; The beeswax ethanol solvent is sprayed on the inner wall of the cylinder.

[0023] Through the foregoing technical solution, beeswax is a fatty substance secreted by the abdomen of worker bees and is used to build honeycombs. It is a natural substance with high safety and is often used in making skin care products, lipsticks, etc. Beeswax has a certain strength and excellent moisture-proof property, and the cost is low.

[0024] The second object of the present invention is to provide a composite paper can that can improve the recyclability after use, thereby increasing the environmental protection performance of the composite paper can.

[0025] To achieve this purpose, the present invention adopts the following technical solutions: A composite paper can is prepared by the composite paper can production method described in any one of claims 1-9, and includes a moisture-proof layer, a barrier layer, a support layer, and a printing layer sequentially arranged from the inside to the outside.

[0026] The beneficial effects of this application: The present invention provides a composite paper can production method. By using a rice paste adhesive to replace the traditional solvent-based glue, the technical effects of reducing VOC emissions and reducing the long-term input cost are achieved. In addition, the process of laminating a polyethylene or polypropylene film to the barrier layer in the prior art is removed, and it is replaced by a method of applying a rice paste adhesive or spraying a beeswax ethanol solution to form a moisture-proof layer, so that the moisture-proof layer not only has a good moisture-proof effect and can effectively block water vapor, but also is safe and environmentally friendly and has good degradability. Description of the drawings

[0027] Figure 1 It is a process flow schematic diagram of this application. Specific embodiments

[0028] In order to easily understand the technical means, creative features, achieved objectives and effects of this application, the following further elaborates this application in conjunction with specific illustrations.

[0029] This application provides a method for producing a composite paper can. The composite paper can includes a moisture-proof layer, a barrier layer, a support layer, and a printing layer that are sequentially arranged from the inside to the outside. As Figure 1 shown, its production method includes the following steps: S100, perform surface treatment on the support layer Remove the particulate matter on the surface of the support layer. The support layer is selected from kraft paper or white cardboard. The process of removing the surface particulate matter can be carried out by ultrasonic dust removal cleaning, or high-pressure suction of particulate matter after shaking, or other conventional methods.

[0030] S110, process a first adhesive layer on the side of the support layer Straighten and convey the support layer. During the conveying process, apply rice paste adhesive to one side of the support layer, and form a first adhesive layer on the surface of the support layer. The rice paste adhesive can be applied through a cloth glue roller or other common mechanisms.

[0031] During the continuous conveying process, scrape the first adhesive layer to remove the excess rice paste adhesive and make the first adhesive layer more flat.

[0032] Optionally, the position of scraping the glue is located at the position where the support layer is on one or more conveying rollers during the conveying process of the support layer. Because the support layer located on the conveying roller is closely attached to the surface of the conveying roller under the support of the conveying roller, it is more suitable for scraping the glue and will not damage the support layer.

[0033] Furthermore, the specific thickness of the first adhesive layer after scraping the glue is set according to actual adhesion requirements, and the maximum thickness of the first adhesive layer does not exceed 0.35mm, which not only ensures that the first adhesive layer has strong adhesion and will not dry quickly, but also avoids the overflow of glue in subsequent processes due to too large a thickness of the first adhesive layer.

[0034] S120, hot press and composite the support layer and the barrier layer Convey the barrier layer above the first adhesive layer for hot press and composite to form a composite material layer. The hot press and composite temperature is 70-80 degrees Celsius, the pressure is 0.2-0.6 Mpa, and the time is 30-60 seconds. The barrier layer is selected from aluminum foil, aluminized film or other barrier materials. Specifically, the hot press and composite process can be carried out on a hot press roller or a hot press roller combined with a drying channel, or other conventional structures that can perform hot pressing.

[0035] Optionally, while performing hot press and composite, perform negative pressure air extraction on the composite material layer to extract the water vapor generated from the first adhesive layer, accelerate the drying of the first adhesive layer, and thus improve the efficiency of hot press and composite.

[0036] Furthermore, the extracted water vapor is input into the rice paste adhesive for heat recovery, and in combination with other conventional heating structures, the rice paste adhesive is kept at 30-45 degrees Celsius to avoid reduced fluidity of the rice paste adhesive due to low temperature. At the same time, the water vapor can make up for the moisture lost by the rice paste adhesive during the insulation process.

[0037] S130, winding the composite material layer to form a cylinder In one embodiment, the composite material layer is spirally wound with a 1-2 mm overlap at the seam and bonded by UV curing agent glue. The UV curing agent glue is cured by ultraviolet radiation so that the composite material layer is shaped into a cylinder with two ends opened.

[0038] In another embodiment, the composite material layer is flat-rolled, that is, the composite material is laid flat and then vertically rolled, with the seams overlapping by no less than 0.5 cm, and the seams are heat-sealed or otherwise securely connected to form a cylinder or square cylinder with openings at both ends or a cylinder with other cross-sectional shapes.

[0039] S140, processing moisture-proof layer on the inner wall of the cylinder In one embodiment, the rice paste adhesive is applied to the inside of the cylinder, and a moisture-proof layer is formed after drying. The specific application process can be performed by using a manipulator in conjunction with a rubber roller or a gluing scraper. Optionally, according to the actual thickness requirement of the moisture-proof layer, the rice paste adhesive can be applied once or multiple times. After each application, the cylinder is rotated around the axis using tools such as a manipulator and a transmission channel, and the rotation speed does not exceed 10r / s. The centrifugal force is used to make the rice paste adhesive inside the cylinder more uniform and smooth, and the centrifugal force needs to be continuously applied to the cylinder during the drying process.

[0040] In another embodiment, beeswax ethanol solvent is sprayed on the inside of the cylinder, and a moisture-proof layer is formed after drying. Specifically, a beeswax ethanol solvent with a mass fraction of 2-3% is selected. Specifically, the beeswax ethanol solvent can be sprayed on the inside of the cylinder once or multiple times according to the actual requirements for the thickness of the moisture-proof layer, and the amount of each spraying is 2-4g / m².

[0041] S150, composite printing layer and cylinder The printing layer is conveyed and rice paste adhesive or UV curing agent glue is applied on the side of the printing layer away from the printing surface to form a second adhesive layer. The side of the printing layer with the second adhesive layer is wrapped around the outer wall of the cylinder, and the excess printing layer is cut off after wrapping once. After the second adhesive layer is cured, the printing layer and the cylinder are compounded to form a paper tube.

[0042] S160, cutting paper tube According to the marked positions on the printing surface of the outer wall of the paper tube, the paper tube is cut to form multiple preliminary cans. Specifically, the printing surface of the printing layer on the paper tube has paper can printing patterns with multiple units along the axial direction of the paper tube, and the marked positions are between adjacent printing patterns. Specifically, the cutting of the paper tube can be carried out by a slitter or other cutting tools.

[0043] S170, sealing the bottom of the preliminary can The bottom of the preliminary can is sealed, and the bottom of the preliminary can is judged according to the up and down of the printing pattern on its outer wall.

[0044] Specifically, the preparation process of the rice paste adhesive is as follows: S200, take corresponding weight parts of glutinous rice and water and mix them, heat and cook them to obtain cooked glutinous rice. Specifically, the weight fraction ratio of glutinous rice to water is 1:1.2, and the aforementioned ratio can also be adjusted adaptively according to different cooking containers, such as any value in the range of 1:1.2 - 1:2.

[0045] S210, take the cooked glutinous rice and the same weight part of water, stir and crush them in an environment with a temperature of 80 - 90 degrees Celsius to form rice paste, and the stirring time is adjusted according to the weight part of the cooked glutinous rice. Continuously heat and stir and add another part of water with the same weight as the cooked glutinous rice. Observe the fluidity and color of the rice paste every 10 - 15 minutes until the rice paste presents a milky white color and there is no obvious clear water, that is, the rice paste does not layer after standing for 5 minutes.

[0046] S220, cool the rice paste to 50 - 55 degrees Celsius, filter the rice paste, and the filtration mesh number is 80 - 100 meshes to make the rice paste more delicate.

[0047] S230, take 1 / 6 - 1 / 4 of the weight part of the glutinous rice of plant ash, sieve it and add it to the rice paste and mix evenly to obtain the rice paste adhesive. Cool the rice paste adhesive to 30 - 45 degrees Celsius and keep it warm for use.

[0048] The preliminary cans prepared by the method of this application are packed and sold after food is loaded and the top is sealed. The preliminary paper cans that have been sold and completed their mission are recycled. The preliminary paper cans can be directly crushed to form mixed scraps, and the mixed scraps are remade into recycled paper with the required thickness as the raw material of the paper. Since the recycled paper contains aluminum foil or aluminized film, it has a certain barrier effect. After the recycled paper is rolled into a cylindrical structure, a moisture-proof layer is processed inside the cylindrical structure, and it can be used again as a paper can packaging for foods with low requirements for light avoidance, thereby further improving the resource utilization rate. In addition, the recycled paper can also be used as a support layer to be recycled into the production of the aforementioned preliminary paper cans, or the recycled paper can be used as a material for making other paper utensils for recycling.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. Without departing from the spirit and scope of the present application, there will be various changes and improvements to the present application, and these changes and improvements all fall within the scope of protection required by the present application. The scope of protection required by the present application is defined by the appended claims and their equivalents.

Claims

1. A method for producing a composite paper can, characterized in that: It includes the following steps: Straighten and transport the support layer; Apply rice paste adhesive on one side of the support layer to form a first adhesive layer; Transport the barrier layer above the first adhesive layer and perform hot press lamination to form a composite material layer; Wind and shape the composite material layer to form a cylinder; Process a flowable moisture-proof material on the inner wall of the cylinder, and after drying, form a moisture-proof layer; Transport the printing layer to the outside of the cylinder and perform adhesion to form a paper tube.

2. The production method of the composite paper can according to claim 1, characterized in that: The rice paste adhesive includes cooked glutinous rice and water, and the weight ratio of cooked glutinous rice to water is 1:(1.2 - 2).

3. The production method of the composite paper can according to claim 2, characterized in that: The rice paste adhesive includes plant ash.

4. The production method of the composite paper can according to claim 3, characterized in that: The rice paste adhesive is prepared by the following method: Take glutinous rice and water, and obtain cooked glutinous rice after steaming; Take the corresponding weight portions of cooked glutinous rice and water and mix them evenly until they are broken and fused and do not separate when standing still to obtain glutinous rice paste; Take the corresponding weight portions of plant ash, add it to the glutinous rice paste and mix evenly to obtain the rice paste adhesive, and keep the rice paste adhesive at 30 - 45 °C for standby.

5. The production method of the composite paper can according to claim 1, characterized in that: After applying the rice paste adhesive on one side of the support layer, scrape the first adhesive layer to make the thickness of the first adhesive layer not exceed 0.35 mm.

6. The production method of the composite paper can according to claim 1 or 4, characterized in that: When performing hot press lamination on the main barrier layer and the support layer, perform negative pressure air extraction on the first adhesive layer to extract water vapor and recycle the water vapor.

7. The production method of the composite paper can according to claim 1, characterized in that: When winding and shaping the composite material layer, adopt a spiral winding method, and fix the joint with UV curing agent glue.

8. The production method of the composite paper can according to claim 1, characterized in that: When processing the flowable moisture-proof material on the inner wall of the cylinder, the flowable moisture-proof material is the rice paste adhesive; The rice paste adhesive is applied to the inner wall of the cylinder, and the cylinder is rotated to apply centrifugal force to the pastoral household adhesive to make it uniform.

9. The production method of the composite paper can according to claim 1, characterized in that: When processing the flowable moisture-proof material on the inner wall of the cylinder, the flowable moisture-proof material is beeswax ethanol solvent; The beeswax ethanol solvent is sprayed on the inner wall of the cylinder.

10. A composite paper can, characterized in that: Prepared by the composite paper can production method according to any one of claims 1 - 9, including a moisture-proof layer, a barrier layer, a support layer, and a printing layer arranged in sequence from the inside to the outside.

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