Production process of energy-saving and fast drying and dehydrating paper plastic products

Abstract

The present invention is a production process method for paper-plastic products with energy saving and rapid drying and dehydration, and particularly refers to a process application in the production of paper-plastic products. The present invention mainly comprises a cold extrusion station which is independent and arranged between a slurry suction molding station and a hot pressing molding station. The cold extrusion station is provided with an upper and a lower mold which can form a mold gap according to the shape and size of the product. The mold gap is used to squeeze out about 30%-50% of the moisture of the preform product, and then the preform product is sent to the hot pressing molding station to be continuously dehydrated to less than 3% to form a paper-plastic product. The paper-plastic product produced by the present invention can shorten the production time and reduce the drying heat energy consumption.

Description

Technical Field

[0001] The invention relates to a production process for paper-plastic products, in particular to a production process method for paper-plastic products with energy saving and rapid drying and dehydration. Background Art

[0002] With the deepening of the concept of environmental protection and the demand for it, the technical improvement of the production process of degradable and recyclable products has become increasingly important, especially the non-toxic, degradable, recyclable and reproducible characteristics of paper and plastic products made of herbal plant fibers have become the vanguard of environmentally friendly products. The production process of paper and plastic products is nothing more than: continuous production processes such as slurry suction molding, hot pressing and trimming. Among them, how to reduce heat energy loss and reduce the time of hot pressing and shaping is a technical field that the technical personnel in the paper and plastic product manufacturing industry have long been eager to break through; the general slurry suction process uses vacuum slurry suction technology to form the initial embryo of paper and plastic products. At this time, the moisture content of the initial embryo is about 70%-80%, and then various heating and dehydration technologies are used to dry the initial embryo. However, in the process of using thermal power to directly reduce the moisture content of the initial embryo to below 3%, the heat loss is quite huge, and it takes a lot of time to complete. The heat energy and time consumed in this process are obviously contrary to the concept of environmental protection, and at the same time greatly increase the production cost, and greatly reduce the profit of paper and plastic products completed by using this production process.

[0003] Another improved paper plastic production process is known to be: slurry suction molding, cold pressing dehydration, hot pressing shaping and trimming. After slurry suction molding, a cold pressing mold is used to directly close the slurry suction mold at the slurry suction molding station to squeeze the embryo in the slurry suction mold and discharge the squeezed water, which can reduce the moisture content of the embryo from 70%-80% to 50%-60% to form a wet embryo. The wet embryo is then moved to the hot pressing shaping station for dehydration to a moisture content of less than 3% to form a semi-finished product. However, the conventional cold pressing dehydration process is used for squeezing and dehydration. Please refer to Figures 4 to 6 The pulp suction mold 91 is provided with a first air-permeable net 93 for pulp suction and filtering. The first air-permeable net 93 is a sheet-like first air-permeable net 93 composed of a plurality of crisscrossing mesh lines. Figure 6 As shown, the first air-permeable net 93 is formed with a plurality of meshes 930. When the extrusion die 92 is pressed, the surface of the first semi-dry and wet embryo product M in contact with the slurry absorption die 91 sinks into the meshes 930 of the first air-permeable net 93, resulting in a bite and sticking phenomenon, as shown in FIG. Figure 5As shown, in the currently known cold-pressed paper-plastic product production process, only the first half dry-wet embryo M with a larger mold withdrawal angle can be demolded. If the first half dry-wet embryo M with a small withdrawal angle or close to a vertical plane is encountered, its surface will be scratched by the first breathable net 93 during demolding, and it cannot be demolded smoothly or the pulp fibers will be broken to cause pore blockage. At the same time, the withdrawal angle of the mold imposes many restrictions on the shape or angle when producing paper-plastic products.

[0004] Furthermore, if the initial embryo product is squeezed directly on the slurry absorption mold 91 by using the extrusion mold 92, and only the squeezing and dehydration are considered without calculating the mold clearance after extrusion (i.e., the thickness of the initial embryo product after being squeezed), it is easy to cause the thickness of the first half dry and wet embryo product M to be too thick or too thin. Inappropriate thickness will cause a higher defective rate of the initial embryo product after the finished product; if the thickness of the first half dry and wet embryo product M is too thick, the paper-plastic product will have yellow spots; if the thickness of the first half dry and wet embryo product M is too thin, the bursting resistance, folding resistance and strength of the paper-plastic product will be too low, and the surface of the finished product will also have obvious uneven textures. This is a defect of the currently known use of cold pressing and dehydration technology as a means of producing paper-plastic products, and it also makes it impossible to improve production efficiency and increase production costs. Summary of the invention

[0005] The main purpose of the present invention is to provide a production process method for paper-plastic products with energy saving and rapid drying and dehydration, which is a cold extrusion station composed of an upper mold and a lower mold for extruding a primary embryo product, and the cold extrusion station is arranged between a slurry suction molding station and a hot pressing and shaping station, so that the overall process flow is slurry suction molding-cold extrusion-hot pressing and shaping, and the upper mold and the lower mold of the cold extrusion station can form a mold gap when the mold is closed, and the extrusion force after the upper mold and the lower mold are closed is used to squeeze the primary embryo product; based on the thickness of a finished product, that is, the mold gap of the hot pressing and shaping station is also maintained at the thickness of the finished product. Distance, according to the setting of the distance of the thickness of the finished product, the thickness of the semi-finished product after drying at the hot pressing and shaping station is also maintained at the distance of the thickness of the finished product, the distance of the mold gap of the aforementioned cold extrusion station is 1~1.3 times the thickness of the finished product, that is, the distance of the mold gap of the cold extrusion station is between 1~1.3 times the thickness of the finished product, and the thickness of the semi-dry and wet embryos pressed out of the cold extrusion station is also maintained at 1~1.3 times the thickness of the finished product, and the distance of the mold gap of the aforementioned slurry suction molding station is 2~2.3 times the thickness of the finished product, that is, the thickness of the initial embryos formed by the slurry suction molding station is also maintained at 2~2.3 times the thickness of the finished product.

[0006] Preferably, a vacuum cavity is formed at the bottom of the lower mold of the aforementioned cold extrusion station, and a containing space for placing the preliminary embryo is provided on the other side of the lower mold, and a forming mold surface having the same shape as the aforementioned preliminary embryo is provided in the containing space for positioning and shaping the aforementioned preliminary embryo, and a plurality of air holes are provided between the aforementioned vacuum cavity and the aforementioned containing space, and the air holes penetrate between the aforementioned vacuum cavity and the aforementioned containing space for the aforementioned slurry suction molding station, the cold extrusion station, and the hot pressing shaping station to extract moisture by vacuum negative pressure.

[0007] Preferably, the mold surface of the lower mold with a demoulding angle greater than 5 degrees is provided with a breathable net, while the mold surface of the lower mold with a demoulding angle less than 5 degrees is not provided with the breathable net.

[0008] Preferably, after the slurry suction molding station enters the slurry tank to absorb slurry and form the aforementioned embryonic product, the embryonic product is transferred to the accommodating space of the lower mold of the aforementioned cold extrusion station. When the upper mold and the lower mold are combined for extrusion, the embryonic product is completely attached to the molding die surface of the lower mold and the aforementioned breathable net by the extrusion force of the upper mold and the adsorption force of the vacuum negative pressure, so that the thickness of the embryonic product is formed from the thickness of the initial slurry suction molding station to the thickness of the extrusion formed by the aforementioned cold extrusion station, and the moisture of the compressed embryonic product is squeezed out and discharged from the surface The discharged water is then adsorbed into the vacuum chamber through the pores by the vacuum negative pressure and then discharged from the lower mold. The moisture content of the initial embryo is reduced from 68%-75% to 55%-60%, thereby obtaining a semi-dry embryo with a lower moisture content. The semi-dry embryo is then transferred to the hot pressing and shaping station. The free water on the surface of the semi-dry embryo and the bound water inside the semi-dry embryo are completely vaporized and evaporated by the pressurization and heating drying of the heating system, so that the moisture content of the semi-dry embryo is reduced from 55%-60% to below 3% to obtain a semi-finished product.

[0009] Preferably, the drying time ratio of the preliminary embryo product which passes through the aforementioned cold extrusion station and then moves to the aforementioned hot pressing and shaping station for heating and drying and the drying time ratio of the preliminary embryo product which does not pass through the aforementioned cold extrusion station and directly moves to the aforementioned hot pressing and shaping station for heating and drying is 1:2, and the heat energy consumption ratio is 2:3.

[0010] After adopting the above technical scheme, the present invention maximizes the dehydration and drying of the three processes of vacuum slurry suction dehydration, cold extrusion dehydration and hot pressing and drying, that is, taking the thickness of a finished product as a reference, the distance of the die gap of the slurry suction molding station is set to 2-2.3 times the thickness of the finished product, and the moisture content of the initial embryo A is first reduced to the limit of 68%-75% by vacuum slurry suction dehydration, and then the distance of the die gap of the cold extrusion station is set to 1-1.3 times the thickness of the finished product, and the cold extrusion is used to dehydrate to a semi-dry and wet embryo B with an optimal moisture content of 50%-60%, and then the die gap of the hot pressing and shaping station is set to be kept at the distance of the thickness of the finished product, and the semi-dry and wet embryo B is dried to a semi-finished product C with a moisture content of less than 3% by hot pressing and drying. The means used in the entire process are all maximized applications of the station, without wasting time and energy for unnecessary consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram showing the process of the present invention and the moisture content and thickness change of the initial embryo product.

[0012] Figure 2 It is a schematic diagram of the cold extrusion die clamping of the present invention.

[0013] Figure 3 This is a schematic diagram of the lower mold structure of the cold extrusion pressing station of the present invention.

[0014] Figure 4 It is a schematic diagram of the conventional cold pressing extrusion die and the slurry suction die pressing.

[0015] Figure 5 This is a schematic diagram of the bite-bonding between the wet embryo and the breathable mesh using conventional cold pressing technology.

[0016] Figure 6 This is a schematic diagram of a breathable net.

[0017] Explanation of symbols:

[0018] 1...Slurry suction molding station

[0019] 2...Cold extrusion station

[0020] 21... Upper mold

[0021] 22... Lower mold

[0022] 221...Accommodation space

[0023] 222...Molding surface

[0024] 223...Vacuum chamber

[0025] 224...Stomach

[0026] 225...Mold clearance

[0027] 3...Hot pressing and shaping station

[0028] 4...Breathable mesh

[0029] 91...Slurry suction mold

[0030] 92...Extrusion die

[0031] 93...The first breathable mesh

[0032] A...Preliminary product

[0033] B...Semi-dry and wet embryo products

[0034] C...Semi-finished products

[0035] X...Finished product thickness

[0036] M...The first half of the wet and dry embryo products. DETAILED DESCRIPTION

[0037] Please refer to Figures 1 to 3As shown, the present invention provides a production process method for energy-saving and fast drying and dehydrating paper plastic products, which mainly comprises an upper mold 21 and a lower mold 22 combined to form an independent cold extrusion station 2 for extruding a primary embryo product A. The cold extrusion station 2 is arranged between a slurry suction molding station 1 and a hot pressing shaping station 3, so that the overall process flow is slurry suction molding-cold extrusion-hot pressing shaping. The upper mold 21 and the lower mold 22 of the cold extrusion station 2 can form a mold gap 225 when the mold is closed, and the extrusion force after the upper mold 21 and the lower mold 22 are closed is used to squeeze the primary embryo. Product A; taking a finished product thickness X as a reference, that is, the mold gap of the aforementioned hot pressing and shaping station 3 is also maintained at the distance of the finished product thickness X. According to the setting of the distance of the finished product thickness X, the thickness of the semi-finished product C after drying at the hot pressing and shaping station 3 is also maintained at the distance of the finished product thickness X. The distance of the mold gap of the aforementioned cold extrusion station 2 is 1 to 1.3 times the finished product thickness X, that is, the distance of the mold gap of the cold extrusion station 2 is between 1 and 1.3 times the finished product thickness X. The thickness of the semi-dry and wet embryo product B squeezed out by the cold extrusion station 2 is also maintained at 1 to 1.3 times the finished product thickness X, and the aforementioned suction The distance of the mold gap of the slurry forming station 1 is 2 to 2.3 times the thickness X of the finished product, that is, the thickness of the preform A formed by the slurry forming station 1 is also maintained at 2 to 2.3 times the thickness X of the finished product; a vacuum cavity 223 is formed at the bottom of the lower mold 22 of the cold extrusion press station 2, and a receiving space 221 for placing the preform A is provided on the other side of the lower mold 22, and a molding die surface 222 having the same shape as the preform A for positioning and shaping the preform A is provided in the receiving space 221, and a plurality of air holes 22 are provided between the vacuum cavity 223 and the receiving space 221. 4, the air hole 224 is passed through between the aforementioned vacuum chamber 223 and the aforementioned accommodating space 221 for the vacuum negative pressure of the aforementioned slurry suction molding station 1, the cold extrusion pressing station 2, and the hot pressing shaping station 3 to extract moisture; the aforementioned molding die surface 222 is a die surface with different angles to match the shape of the paper plastic product. A breathable net 4 is provided on the die surface of the aforementioned lower mold 22 with a demolding angle greater than 5 degrees, while the die surface of the lower mold 22 with a demolding angle less than 5 degrees is not provided with the aforementioned breathable net 4, but the molding die surface 222 without the aforementioned breathable net 4 still has air holes 224 passing through between the aforementioned die surface and the aforementioned vacuum chamber 223.

[0038] Technical personnel familiar with the paper and plastic product industry know that if the cost of dehydration by vacuum suction dehydration is taken as the benchmark and is 1, then the cost ratio of vacuum suction dehydration, cold extrusion dehydration and hot press drying dehydration is 1:70:330, that is, under the same dehydration amount, the cost reduction of the cold extrusion dehydration is 70 times that of the vacuum suction dehydration, and the cost reduction of the aforementioned hot press drying dehydration is about 5 times that of the aforementioned cold extrusion dehydration; the dehydration characteristics of different drying methods are as follows: the aforementioned vacuum suction dehydration can only absorb the free water on the surface of the aforementioned embryo A, so its dehydration effect is very limited, and it can only discharge about 10%-15% of the free water of the aforementioned embryo A; the aforementioned cold extrusion dehydration is to use the extrusion force to compress the thickness of the aforementioned embryo A The paper is pressed and thinned, so that the water in the aforementioned embryo product A is squeezed and discharged. The proportion of water discharged varies according to the thickness and shape of different paper plastic products. The water that can be discharged is about 30%-50% of the water content of the aforementioned embryo product A. However, the aforementioned cold extrusion dehydration can only discharge free water, and cannot discharge bound water from the interior of the aforementioned embryo product A; the aforementioned hot pressing and drying dehydration is to use heat energy to vaporize the free water on the surface of the aforementioned embryo product A and the bound water inside, and the water content of the paper plastic product can be dried to less than 3%. According to the size, shape and thickness of the paper plastic product, the aforementioned hot pressing and drying dehydration time varies greatly, but the lower the water content of the aforementioned embryo product A, the shorter the aforementioned hot pressing and drying dehydration time, and the relative heat energy consumption is also reduced.

[0039] The specific implementation method of the present invention is as follows: a cold extrusion station 2 of the present invention is arranged between the aforementioned slurry suction molding station 1 and the aforementioned hot pressing and shaping station 3. After the aforementioned slurry suction molding station 1 enters the slurry tank to absorb slurry and form the aforementioned preliminary blank A, the preliminary blank A is transferred to the accommodating space 221 of the lower mold 22 of the aforementioned cold extrusion molding station 2. When the aforementioned upper mold 21 and the lower mold 22 are combined for extrusion, the aforementioned preliminary blank A is completely attached to the molding die surface 222 of the lower mold 22 and the aforementioned breathable net 4 by the pressure of the extrusion force of the upper mold 21 and the adsorption force of the vacuum negative pressure, so that the thickness of the aforementioned preliminary blank A is formed from the initial thickness 2X-2.3X formed by the slurry suction molding station 1 to the thickness 1X-1.3X formed by the extrusion of the aforementioned cold extrusion molding station 2. The aforementioned compressed preliminary blank A is completely attached to the molding die surface 222 of the lower mold 22 and the aforementioned breathable net 4 by the pressure of the upper mold 21 and the adsorption force of the vacuum negative pressure. The moisture of the initial embryo A is squeezed out and discharged from the surface, and the discharged moisture is then adsorbed to the vacuum chamber 223 through the air holes 224 by the vacuum negative pressure and then discharged from the lower mold 22, and the moisture content of the initial embryo A is reduced from the original 68%-75% to 50%-60%, thereby obtaining a semi-dry and wet embryo B with a lower moisture content; the semi-dry and wet embryo B is then transferred to the aforementioned hot pressing and shaping station 3, and the free water on the surface of the semi-dry and wet embryo B and the bound water inside can be completely vaporized and evaporated by the pressurization and heating drying of the heating system, so that the moisture content of the semi-dry and wet embryo B is reduced from 50%-60% to less than 3% to obtain a semi-finished product C; in addition, the extrusion force and the vacuum negative pressure suction force have been disclosed in other conventional patent documents, so they will not be repeated here.

[0040] The above implementation method is tested in the following actual process: if the initial embryo A with a moisture content of 72.8% is directly dried to the aforementioned hot pressing and shaping station 3 to a semi-finished product C with a moisture content of 1.4% without passing through the aforementioned cold extrusion station 2, the drying time required is 29 seconds; if the initial embryo with the same moisture content of 72.8% is first extruded for 10 seconds through the cold extrusion station 2 of the present invention, a semi-dry and wet embryo B with 33.3% of moisture removed can be obtained, and then the semi-dry and wet embryo B after pressing is moved to the aforementioned hot pressing and shaping station 3 for hot pressing and drying for 15 seconds to obtain a semi-finished product C with a moisture content of 1.4%; it is known from the above experimental data that the initial embryo A with a moisture content of 72.8% is dried to a semi-finished product of 1.4% through two different drying and dehydration processes, and there is no The initial embryo product A that has passed through the aforementioned cold extrusion station 2 needs to use 29 seconds of drying time; while the initial embryo product A that has passed through the aforementioned cold extrusion station 2 only needs 15 seconds of drying time to complete, and the drying time ratio used by the two is 2:1; the 33.3% moisture removed by the above-mentioned cold extrusion station 2 is the heat energy consumed by the hot pressing and shaping station 3 that can be saved, that is, 33.3% of the heat energy consumption is saved, and the heat energy consumption ratio of the two is 3:2; but under different mold designs, product shapes, size thickness and other factors, the ratio of drying time will be different, but in any case, the initial embryo product A that has been squeezed out of moisture in the cold extrusion station 2 of the present invention is definitely dried to the semi-finished product C. The time is definitely shorter, and the required heat energy consumption is also less.

[0041] According to the test results, the moisture content of the semi-dry wet embryo B after the cold extrusion station 2 differs by 33.3% from that of the unpressed embryo A. The time for drying to a moisture content of 1.4% is 15 seconds and 29 seconds respectively. The test results of the two differ by 14 seconds in total, that is, the moisture squeezed by adding the cold extrusion station 2 can save 14 seconds of energy consumption and drying time; the difference of 20 seconds is due to the fact that the embryo A contains more moisture, so that when the hot pressing and shaping station 3 is hot-pressed and dried, the lower mold 22 is cooled by the moisture and takes away more heat when evaporated. Therefore, the hot pressing and shaping mold that has not passed through the cold extrusion station 2 must be replenished to the default heating temperature, and more moisture needs to be dried and evaporated, so more time is needed; compared with the semi-dry wet embryo B after the cold extrusion station 2, the moisture content is lower, and the cooling effect on the hot pressing and shaping mold is smaller, so the hot pressing and shaping mold has a faster temperature replenishment and evaporation speed.

[0042] In summary, the present invention maximizes the dehydration and drying processes of vacuum suction dehydration, cold extrusion dehydration and hot press drying dehydration, that is, vacuum suction dehydration is used to reduce the moisture content of the initial embryo A to the limit of 68%-75%, and then cold extrusion dehydration is used to reduce the moisture content to a semi-dry embryo B with an optimal moisture content of 50%-60%, and then hot press drying dehydration is used to dry the semi-dry embryo B to a semi-finished product C with a moisture content of less than 3%. The means used in the entire process are all maximized applications of the workstation without wasting time and energy consumption.

Claims

1. A production process for energy-saving and fast drying and dehydrating paper plastic products, which is a cold extrusion station composed of an upper mold and a lower mold for extruding a primary embryo product, the cold extrusion station is arranged between a slurry suction molding station and a hot pressing shaping station, so that the overall process flow is slurry suction molding-cold extrusion-hot pressing shaping, characterized in that: The upper and lower molds of the cold extrusion station form a mold gap when they are molded together, and use the extrusion force of the upper and lower molds after the molds are molded together to squeeze the preliminary embryo product; based on the thickness of a finished product, that is, the mold gap of the hot pressing and shaping station is also maintained at a distance of the thickness of the finished product. According to the setting of the distance of the finished product thickness, the thickness of the semi-finished product after drying at the hot pressing and shaping station is also maintained at a distance of the thickness of the finished product. The distance of the mold gap of the cold extrusion station is 1 to 1.3 times the thickness of the finished product, that is, the distance of the mold gap of the cold extrusion station is between 1 and 1.3 times the thickness of the finished product. The thickness of the semi-dry and wet embryo product squeezed out by the cold extrusion station is also maintained at The thickness of the finished product is 1 to 1.3 times that of the finished product, while the distance of the mold clearance of the aforementioned slurry suction molding station is 2 to 2.3 times that of the finished product, that is, the thickness of the preform formed by the slurry suction molding station is also maintained at 2 to 2.3 times that of the finished product; a vacuum cavity is formed at the bottom of the lower mold of the aforementioned cold extrusion station, and a receiving space for the preform is provided on the other side of the lower mold, and a forming die surface having the same shape as the aforementioned preform is provided in the receiving space for positioning and shaping the aforementioned preform in the receiving space, and a plurality of air holes are provided between the aforementioned vacuum cavity and the aforementioned receiving space, and the air holes are penetrated between the aforementioned vacuum cavity and the aforementioned receiving space for the aforementioned slurry suction molding station and the cold extrusion station , the vacuum negative pressure of the hot pressing and shaping station extracts moisture; the mold surface of the aforementioned lower mold with a demoulding angle greater than 5 degrees is provided with a breathable net, while the mold surface of the lower mold with a demoulding angle less than 5 degrees is not provided with the breathable net; after the aforementioned slurry suction molding station enters the slurry tank to absorb slurry and form the aforementioned preliminary embryo product, the preliminary embryo product is transferred to the accommodating space of the lower mold of the aforementioned cold extrusion station, and when the aforementioned upper mold and lower mold are combined for extrusion, the aforementioned preliminary embryo product is completely adhered to the molding mold surface of the lower mold and the aforementioned breathable net by the extrusion force of the upper mold and the adsorption force of the vacuum negative pressure, so that the thickness of the aforementioned preliminary embryo product is formed from the thickness of the initial slurry suction molding station to the thickness of the aforementioned cold extrusion molding station. The thickness formed by the extrusion of the station, the compressed initial embryo system is squeezed out of the water and discharged from the surface, and the discharged water is then adsorbed to the vacuum chamber through the aforementioned pores by the vacuum negative pressure and then discharged from the aforementioned lower mold, and the moisture content of the initial embryo is also reduced from the original 68%-75% to 55%-60%, thereby obtaining a semi-dry wet embryo with a lower moisture content; the semi-dry wet embryo is then transferred to the aforementioned hot pressing and shaping station, and the free water on the surface of the semi-dry wet embryo and the bound water inside the semi-dry wet embryo are completely vaporized and evaporated by the pressurization and heating drying of the heating system, so that the moisture content of the semi-dry wet embryo is reduced from 55%-60% to below 3% to obtain a semi-finished product.

Images