Preparation method and device of household paper

Abstract

The invention provides a preparation method of household paper, which comprises the following steps: S1, providing raw paper, and wetting the raw paper to form wet paper; s2, wet paper is clamped and conveyed, the clamping and conveying process is larger than or equal to 3 s, and after clamping and conveying, the moisture content of the wet paper is larger than or equal to 25%; s3, embossing the wet paper to form embossed wet paper; s4, the embossed wet paper is dried to form dry embossed paper, the water content of the dry embossed paper is smaller than or equal to 9%, in this way, water can completely infiltrate the paper, production continuity is guaranteed under the condition that the paper is completely infiltrated, in addition, the bulk of the household paper obtained through treatment of the method is higher, and the quality of the household paper is improved. The bulk of the household paper can reach or exceed the bulk of the household paper of a through air dry / TAD process. The invention further provides a device applying the method.

Description

Technical Field

[0001] The invention relates to a method and a device for preparing daily paper. Background Art

[0002] Cellulose fiber structures are widely used in daily necessities such as toilet paper and napkins. Paper products are usually made of cellulose fiber structures formed by stacking at least one layer of base paper face to face to form a laminate. In order to meet consumers' demand for aesthetics, manufacturers use embossing technology on paper towels containing multiple layers of base paper. The embossing process not only makes the paper towels beautiful, but also increases the surface area of ​​the layer, improves the bulkiness, water holding capacity and softness.

[0003] In order to make the daily paper have better bulk and touch, people have found that humidifying or wetting the paper before embossing, and then embossing and drying it can form daily paper with better bulk and better touch, as shown in documents such as CN110914048A.

[0004] Specifically, the humidification or wetting method is to humidify or moisten the paper by spraying water, but: 1. When the paper is humidified or moistened by spraying water, the strength of the paper will drop significantly. Studies have shown that when the moisture content of the paper reaches 20%, the strength of the paper will drop by more than 40%. However, a certain tension must be maintained during the production process to keep the paper flat and not wrinkled, and to maintain production continuity. Therefore, when water is sprayed on the paper in the humidification-embossing-drying process, it generally does not exceed 20% to avoid the paper strength being too low, resulting in production interruption, such as the range given in ES2578830B1.

[0005] 2. As pointed out in US20060278357A1 and US20110020605A1, water equivalent to 100% of the weight of the base paper can be sprayed. However, in practice, the method pointed out in US20060278357A1 and US20110020605A1 is usually used as a process step after adding components such as moisturizers (creams). Since the moisturizers (creams) added in the previous process contain high-viscosity ingredients such as glycerin, the water actually stays on the surface of the paper or the shallow layer of the paper, and does not infiltrate too much into the inside of the paper, thereby maintaining sufficient strength of the paper to ensure production. At the same time, in order to ensure that the moisturizer and other ingredients can completely infiltrate the paper, it is usually necessary to seal the paper for post-ripening after the entire production is completed.

[0006] In further research, it was found that when the method shown in CN110914048A and the like is adopted, when no moisturizer or other ingredients are added or coated before spraying water, that is, when the paper only undergoes a wetting-embossing-drying process, it must be carried out quickly to avoid the water completely soaking the paper, so as to maintain the paper with sufficient strength to maintain the continuity of production, that is, even if more water is sprayed, when the paper is embossed, only the paper surface contains water, and the inside of the paper is still in a dry state to maintain the strength. However, this method still makes the bulkiness after embossing insufficient, and there is still room for further improvement.

[0007] Therefore, it is necessary to provide a new solution to solve the above problems. Summary of the invention

[0008] To this end, the present invention provides a method for preparing household paper to solve the above technical problems.

[0009] A method for preparing household paper, comprising: S1: providing base paper and wetting the base paper to form wetted paper; S2: The moistened paper is clamped and transported for a period of 3 seconds or longer. After the process, the moisture content of the moistened paper is greater than or equal to 25%. S3: embossing the moistened paper to form an embossed wet paper; S4: drying the embossed wet paper to form dry embossed paper, wherein the moisture content of the dry embossed paper is less than or equal to 9%.

[0010] Among them, in step S1, the base paper is moistened by spraying water, and the water sprayed on the base paper only includes liquid water and does not contain components that increase or decrease viscosity. At the same time, water is sprayed on the base paper surface in the form of water mist, and the particle size of the water mist droplets is 0.02mm~0.4mm.

[0011] In the process of clamping and conveying, the moistened paper is in a slight pressure process, and in the process of clamping and conveying, the moistened paper undergoes at least one bending process.

[0012] The moistened paper is clamped and conveyed by a clamping and conveying unit, the clamping and conveying unit includes an upper clamping part and a lower clamping part, a clamping area is formed between the upper clamping part and the lower clamping part, the clamping area includes a first clamping section located upstream and a second clamping section located downstream, the first clamping section and the second clamping section are both straight, the second clamping section is inclined to the first clamping section, and the angle between the first clamping section and the second clamping section is 120° to 165°.

[0013] The height of the first clamping section gradually decreases from upstream to downstream, so that the moistening paper is subjected to gradually increasing pressure from upstream to downstream in the first clamping section.

[0014] Wherein, the first clamping section includes an inlet end, the moistened paper includes a first wet paper entering the clamping area from the inlet end, the upper clamping part includes a plurality of upper rollers and an upper clamping belt wound on the upper rollers, the lower clamping part includes a plurality of lower rollers and a lower clamping belt wound on the lower rollers, the upper rollers include a first upper roller located in the upstream direction and a second upper roller located in the downstream direction, the lower rollers include a first lower roller located in the upstream direction and a second lower roller located in the downstream direction, the upper clamping belt includes a first front contact point connected to the first upper roller, the upper clamping belt includes a first rear contact point closest to the first lower roller, the upper clamping belt includes a front guide section located between the first front contact point and the first rear contact point, the first wet paper conflicts with the front guide section at the first rear contact point, and is separated from the front guide section at the first front contact point, and the front guide section has an angle of 1° to 4° with the first wet paper.

[0015] Wherein, the second clamping section includes an outlet end, the moistening paper includes a second wet paper detached from the outlet end, and the second wet paper detaches from the outlet end after being slightly bent.

[0016] The second lower roller is located behind the second upper roller, the second wet paper includes a wet paper front section and a wet paper rear section located in front of the second lower roller, the wet paper front section and the wet paper rear section are not located in the same plane, and an angle of 165° to 175° is formed between the wet paper front section and the wet paper rear section.

[0017] Among them, in step S3, the moistened paper is embossed by an embossing unit, the embossing unit includes an embossing roller group, the embossing roller group includes an embossing roller and a bottom roller, the embossing roller also includes an annular groove, the annular groove and the bottom roller form an accommodating space, the clamping and conveying unit includes a transfer belt, at least a portion of the transfer belt extends from the clamping and conveying unit and passes through the accommodating space, the moistened paper moves along with the transfer belt to between the embossing roller and the bottom roller, and is formed into an embossed pattern by the embossing protrusion set in the embossing area by the embossing roller.

[0018] The present invention also provides a device for applying the above preparation method, comprising: A humidifying unit, used for moistening the base paper to form moistened paper; A clamping and conveying unit is used to clamp and convey the moistened paper, and the clamping and conveying process is greater than or equal to 3 seconds. After the clamping and conveying, the moisture content of the moistened paper is greater than or equal to 25%; An embossing unit, comprising an embossing roller group for embossing the moistened paper to form an embossed wet paper; The drying unit dries the embossed wet paper to form dry embossed paper, and the moisture content of the dry embossed paper is less than or equal to 9%.

[0019] Beneficial effects: The present invention provides a method for preparing tissue paper, comprising: S1: providing base paper and moistening the base paper to form moistened paper; S2: clamping and conveying the moistened paper, and the clamping and conveying process is greater than or equal to 3s, and after the clamping and conveying, the moisture content of the moistened paper is greater than or equal to 25%; S3: embossing the moistened paper to form embossed wet paper; S4: drying the embossed wet paper to form dry embossed paper, and the moisture content of the dry embossed paper is less than or equal to 9%. Through the above manner, water can completely soak the paper, and the continuity of production is guaranteed when the paper is completely soaked. In addition, the bulkiness of the tissue paper obtained by the above method is higher, and can reach or exceed the bulkiness of the tissue paper obtained by the Through Air Dry (TAD) process. The present invention also provides a device for applying the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a device for preparing household paper according to a first embodiment of the present invention; Figure 2 for Figure 1 Enlarged schematic diagram of area A in the middle; Figure 3 for Figure 1 Enlarged schematic diagram of area B in the middle; Figure 4 A schematic diagram of a device for preparing household paper according to a second embodiment of the present invention; Figure 5 for Figure 5 Schematic diagram of the embossing roller group.

[0021] Component Description: Base paper 101; first wet paper 102; second wet paper 103; embossed wet paper 104; wet paper front section 1031; wet paper rear section 1032; dry embossed paper 105; humidifying unit 11; humidifying device 111; first conveying unit 112; clamping conveying unit 12; first clamping section 1201; second clamping section 1202; upper clamping part 121; upper roller 1211; upper clamping belt 1212; guide section 1212a; first front contact point 1212b; first rear contact point 1212c; first upper support ...b; first front contact point 1212c; first upper support roller 1211; upper clamping belt 1212; guide section 1212a; first front contact point 1212 Roller 1213; second upper roller 1214; lower clamping portion 122; lower roller 1221; lower clamping belt 1222; first lower roller 1223; second lower roller 1224; embossing unit 13; embossing roller 131; bottom roller 132; first attachment surface 1321; drying unit 14; first drying roller 140; second attachment surface 1401; hot air boxes 141, 151; suction boxes 142, 152; second drying roller 150; transfer belt 423; embossing area 4310; annular groove 4311. DETAILED DESCRIPTION

[0022] An embodiment of the present invention provides a method for preparing household paper, which specifically includes the following steps.

[0023] S1: providing a base paper 101 and moistening the base paper 101 to form moistened paper.

[0024] The base paper 101 is usually a paper formed by wet forming and corrugating. Specifically, the base paper 101 is a thin paper made of cellulose fiber and processed by pulping, wet forming, Yankee drying, and scraper corrugating. These thin papers have a basis weight of 5 to 70 g / ㎡ and a bulk of 5 to 8 cm³ / g. At the same time, the base paper 101 can also be a base paper 101 with higher thickness and basis weight formed by laminating double or multiple layers of single-layer paper.

[0025] It can be understood that the cellulose fiber can be various papermaking fibers, such as various plant fibers. Usually, the plant fibers are wood pulp fibers, or, such as straw pulp fibers, sugarcane pulp fibers or artificial fibers, etc. The cellulose fiber in the present invention is wood pulp fiber, more specifically, a mixed wood pulp formed by NBKP (bleached sulfate coniferous pulp) and LBKP (bleached sulfate broadleaf pulp), wherein the proportion of NBKP can be 10 to 60%.

[0026] It can be understood that the moisture content of the base paper 101 is usually less than or equal to 9%. The moisture content is also called water content and can be tested with reference to the test method of GB / T462-2023.

[0027] The base paper 101 is moistened by spraying water or applying water to the surface of the base paper 101 through a humidifying unit 11, thereby forming moistened paper. Specifically, the humidifying unit 11 can be a nozzle or a coating roller, that is, water can be sprayed on the paper surface through a nozzle, or the base paper 101 can be passed through a pair of coating rollers with water on the surface so that the surface of the base paper 101 adheres to water and is moistened. It can be understood that since the paper surface will be pressurized by coating, the preferred embodiment is to spray water on the paper surface through a nozzle to moisten the base paper 101.

[0028] It can be understood that there is no limitation on the temperature of the water sprayed onto the base paper 101. Usually, the temperature of the water sprayed may be 1°C to 45°C.

[0029] In addition, in the present invention, the water sprayed onto the base paper 101 should only include liquid water and should not contain other components that increase or decrease the viscosity, such as high-viscosity components such as glycerol.

[0030] It can be understood that these liquid waters penetrate into the space between the fibers constituting the base paper 101 from the outside to the inside during the subsequent transportation process, and loosen the hydrogen bonds between the fibers when penetrating. Preferably, when moistening the base paper 101 by spraying water, it is sprayed on the surface of the base paper 101 in the form of water mist, and the droplet size of the water mist should be small so that the droplets attached to the paper surface can penetrate into the space inside the base paper 101 within a suitable time. However, the particle size of these water mists should not be too small. On the one hand, water mists with too small particle sizes are prone to form suspended droplets in the spray area, affecting the spraying of the base paper 101. On the other hand, droplets that are too small adhere to the paper surface and affect the operation. Studies have shown that the appropriate droplet size is 0.02mm~0.4mm.

[0031] S2: The moistened paper is clamped and conveyed, and the clamping and conveying process is greater than or equal to 3s. After the clamping and conveying, the moisture content of the moistened paper is greater than or equal to 25%.

[0032] It can be understood that after the base paper 101 is wetted, water penetrates into the space between the fibers, debonding the hydrogen bonds between the fibers, which will cause a significant decrease in the strength of the base paper 101. However, by clamping and conveying, the wetted paper is basically not subjected to tension during the conveying process, thereby greatly reducing the damage to the wetted paper caused by the traction force in the later stage.

[0033] It can be understood that the time of the clamping and conveying process should be greater than or equal to 3 seconds, so that the water on the surface of the paper sheet can penetrate into the interior of the fibers, or form complete infiltration. The complete infiltration means that the water can completely fill the pores inside the paper sheet. In addition, in order to achieve complete infiltration of paper sheets with different basis weights, thicknesses, and densities, and to make the paper sheets in the production process have higher consistency after subsequent processing, the time of the clamping and conveying process should be greater than or equal to 6 seconds. In addition, the water should not stay in the paper sheet for too long after complete infiltration. Preferably, the time of the clamping and conveying process should be less than or equal to 12 seconds.

[0034] In addition, after being clamped and conveyed, the moisture content of the moistened paper should be greater than or equal to 25%, so that the paper sheet is completely soaked. In a specific embodiment, the moisture content of the moistened paper is between 30% and 40%.

[0035] Furthermore, during the clamping and conveying process, the moistened paper is in a slight compression process, and during the clamping and conveying process, the moistened paper should undergo at least one bending process to form a squeezing-recovery process for the paper sheet in the bending area, so that the paper sheet can be completely soaked and the excess water inside can be squeezed out, so that the inside of the paper sheet has only appropriate water content.

[0036] Please refer to Figure 1 ,exist Figure 1FIG. 4 shows a device for applying the first embodiment of the above method, wherein the device comprises a clamping and conveying unit 12 for clamping and conveying the dampened paper.

[0037] The clamping and conveying unit 12 includes an upper clamping portion 121 located on the upper side of the moistening paper and a lower clamping portion 122 located on the lower side of the moistening paper. A clamping area is formed between the upper clamping portion 121 and the lower clamping portion 122. The moistening paper is clamped in the clamping area and conveyed to the downstream direction.

[0038] The clamping area includes a first clamping section 1201 located upstream and a second clamping section 1202 located downstream. The first clamping section 1201 and the second clamping section 1202 are both straight-line, and the second clamping section 1202 is inclined to the first clamping section 1201, so that the moistened paper is bent when it is transferred from the first clamping section 1201 to the second clamping section 1202 during the clamping and conveying process, thereby forming a slight squeezing-recovery process.

[0039] Furthermore, the angle between the first clamping section 1201 and the second clamping section 1202 is 120° to 165°, so as to form a slight bending process.

[0040] The upper clamping portion 121 includes a plurality of upper rollers 1211 and an upper clamping belt 1212 wound around the upper rollers 1211, and the lower clamping portion 122 includes a plurality of lower rollers 1221 and a lower clamping belt 1222 wound around the lower rollers 1221. The upper clamping belt 1212 and the lower clamping belt 1222 have the same movement speed and opposite movement directions, so that the moistened paper can be stably clamped and conveyed by the upper clamping belt 1212 and the lower clamping belt 1222, and basically does not bear traction or tension in subsequent operations during the conveying process.

[0041] Furthermore, the height of the first clamping section 1201 gradually decreases from upstream to downstream, and the moistened paper is subjected to gradually increasing pressure from upstream to downstream in the first clamping section 1201, so as to reduce the probability of swelling of the paper sheet after water penetrates into the interior of the paper sheet.

[0042] For further information, please refer to Figure 2 and Figure 3 The first clamping section 1201 includes an inlet end, the second clamping section 1202 includes an outlet end, the moistened paper enters the clamping area from the inlet end, and leaves the clamping area from the outlet end. For the convenience of description, the moistened paper entering the clamping area from the inlet end is called the first wet paper 102, and the moistened paper leaving the clamping area from the outlet end is called the second wet paper 103.

[0043] The upper roller 1211 includes a first upper roller 1213 located in the upstream direction and a second upper roller 1214 located in the downstream direction, the lower roller 1221 includes a first lower roller 1223 located in the upstream direction and a second lower roller 1224 located in the downstream direction, the upper clamping belt 1212 includes a front guide section 1212a located between the first upper roller 1213 and the first lower roller 1223, it can be understood that the upper clamping belt 1212 includes a first front contact point 1212b connected to the first upper roller 1213, it can be understood that the first front contact point 1212b is also the upper clamping belt 1212 and the first upper roller 1213 The separation point of separation, the upper clamping belt 1212 includes a first rear contact point 1212c that is closest to the first lower roller 1223. It can be understood that the front guide section 1212a is a section corresponding to the upper clamping belt 1212 located between the first front contact point 1212b and the first rear contact point 1212c. It can be understood that the first wet paper 102 is in contact with the front guide section 1212a at the first rear contact point 1212c, and is separated from the front guide section 1212a at the first front contact point 1212b. In addition, in this manner, the first upper roller 1213 is located in front of the first lower roller 1223, and the front refers to the upstream direction.

[0044] Furthermore, the front guide section 1212a and the first wet paper 102 have an included angle of 1° to 4°.

[0045] Furthermore, the second wet paper 103 is slightly bent and then separated from the outlet end to slightly discharge excess water, so that the wet paper separated from the clamping area has appropriate moisture content, and the internal water during the embossing process will not cause the entanglement structure formed between the internal fibers to be greatly destroyed during the extrusion process, thereby causing the paper strength to be too low.

[0046] Furthermore, the second lower roller 1224 is located behind the second upper roller 1214, and the rear refers to the downstream direction. The second wet paper 103 includes a wet paper front section 1031 and a wet paper rear section 1032 located in front of the second lower roller 1224. The wet paper front section 1031 and the wet paper rear section 1032 are not located in the same plane, and the wet paper front section 1031 and the wet paper rear section 1032 have an angle of 165° to 175°, so that the second wet paper 103 is separated from the outlet after a slight bend.

[0047] It can be understood that the second wet paper 103 is quickly transferred to the embossing unit 13 for embossing.

[0048] Furthermore, the wet paper rear section 1032 enters the embossing unit 13 for embossing in less than 2 seconds.

[0049] S3: The moistened paper is embossed to form an embossed wet paper 104 .

[0050] Please refer to Figure 1 The moistened paper can be embossed by an embossing unit 13, the embossing unit 13 includes an embossing roller group, the embossing roller group includes an embossing roller 131 and a bottom roller 132, and a predetermined embossing protrusion is provided on the embossing roller 131 to form a predetermined embossing pattern on the moistened paper. In this embodiment, the embossing roller group can be a point-to-point, point-to-flat or point-to-concave embossing form, which is not limited here.

[0051] It can be understood that when the embossing roller group is embossing the moistened paper, the movement speed of the embossing roller group should be the same as the speed at which the clamping and conveying unit 12 clamps and conveys the moistened paper, so as to avoid forming a traction force on the moistened paper that causes the moistened paper to be broken, or causing wrinkles during the embossing process due to the low embossing speed.

[0052] Furthermore, the embossing roller group is a hot embossing roller 131, and a heating device is also provided inside the embossing roller 131 for heating the moistened paper while embossing it so that part of the water evaporates. The heating device can be electric heating, or heating can be achieved by supplying a heating medium to the inside. The heating medium can be high-temperature steam or high-temperature oil, etc.

[0053] In order to make the lower strength moistened paper smoothly enter the embossing unit for embossing, please refer to Figure 4 and Figure 5 In the device provided in the second embodiment of the present invention, the embossing roller 431 further includes an annular groove 4311, and the annular groove 4311 and the bottom roller 432 form an accommodating space, and the clamping and conveying unit further includes a transfer belt 423, and at least a portion of the transfer belt 423 extends from the clamping and conveying unit and passes through the accommodating space, so that the moistened paper conveyed from the outlet end can move along with the transfer belt 423 to between the embossing roller 431 and the bottom roller 432, and the embossing protrusions set by the embossing roller 431 in the embossing area 4310 form an embossing pattern.

[0054] In this embodiment, the annular groove 4311 is arranged in the middle of the embossing roller 431, and the embossing areas 4310 are arranged on both sides of the annular groove 4311. In this way, the embossing roller 431 can still emboss a sufficient area of ​​the moistened paper.

[0055] Furthermore, the transfer belt 423 includes a surface facing the bottom roller 432, and when the transfer belt 423 is located in the annular groove 4311, the surface should be located on the inner side of the surface of the embossing area 4310 to prevent the transfer belt 423 from applying pressure to the moistened paper.

[0056] Furthermore, the transfer belt 423 should be made of elastic material or flexible material. In a preferred embodiment, the transfer belt 423 is made of polyurethane material.

[0057] S4: Drying the embossed wet paper 104 to form dry embossed paper 105, wherein the moisture content of the dry embossed paper 105 is less than or equal to 9%.

[0058] It can be understood that, since the moisture content of the wet paper is relatively high in the present invention, the embossed wet paper 104 should be dried relatively quickly to increase the bulk of the formed dry embossed paper 105 and to make the dry embossed paper 105 have suitable strength.

[0059] In this embodiment, the drying unit 14 includes a first drying roller 140 adjacent to the bottom roller 132, and a gap is included between the first drying roller 140 and the bottom roller 132, the bottom roller 132 includes a first attachment surface 1321 in the upstream direction of the gap, and the first drying roller 140 includes a second attachment surface 1401 in the downstream direction of the gap. After the embossed wet paper 104 passes through the gap along the first attachment surface 1321 of the bottom roller 132, it is transferred to the second attachment surface 1401 and then moves to the downstream direction. At the second attachment surface 1401, the embossed wet paper 104 is dried.

[0060] Furthermore, a hot air box 141 is disposed outside the first drying roller 140 , and the hot air box 141 is configured to blow hot air flow toward the embossed wet paper 104 , thereby drying the embossed wet paper.

[0061] Furthermore, the hot air box 141 is arranged at a position corresponding to the second attachment surface 1401 .

[0062] Furthermore, the first drying roller 140 also includes a side wall and a cavity portion formed by the side wall, a suction box 142 is arranged in the cavity portion, the side wall includes a plurality of through holes, the suction box 142 is connected to the negative pressure device, and negative pressure is formed in the suction box 142, so that the water-containing air flow can be discharged through the suction box 142 on the one hand, and the drying process is accelerated by the negative pressure effect on the other hand.

[0063] Furthermore, a heating device is disposed inside the bottom roller 132 to dry the embossed wet paper 104 on the first attaching surface 1321 .

[0064] Furthermore, a second drying roller 150 is disposed downstream of the first drying roller 140 , and the structure of the second drying roller 150 is substantially the same as that of the first drying roller 140 .

[0065] In a specific embodiment, a suction box 152 is provided on the outer side of the second drying roller 150, and a hot air box 151 is provided on the inner side of the second drying roller 150, so that a hot air flow is blown out of the second drying roller 150, that is, the hot air flow direction of the second drying roller 150 is opposite to the hot air flow direction of the first drying roller 140, in this way, the bulk thickness of the formed dry embossed paper 105 is further improved.

[0066] In addition, when the embossed wet paper 104 is dried by hot air flow, the temperature of the hot air flow is 60 to 200°C, preferably 80 to 160°C.

[0067] The method of the present invention is further described below by a specific embodiment. Example

[0068] The above method was used for preparation, wherein the clamping and conveying time was 5 seconds and the moisture content of the wetted paper was 28%.

[0069] Comparative Example 1: The same base paper 101 as in Example 1 was used, and the surface humidification-embossing-drying process was adopted. The water addition amount was 20%, and the embossing treatment was performed quickly after humidification. The intermediate process from humidification to embossing was less than 2s. The embossing roller 131 was the same as in Example 1.

[0070] Comparative Example 2: The same base paper 101 as in Example 1 is used, and the same embossing roller 131 as in Example 1 is used for embossing treatment.

[0071] Comparative Example 3: TAD process household paper with a basis weight substantially equivalent to that of Example 1.

[0072] The embodiments and comparative examples were tested, and the test results are as follows: project unit Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Single-layer basis weight of base paper g / ㎡ 30.1 29.5 29.8 30.0 Number of base paper layers ply 2 2 2 2 Base paper BBW (bulk) cm³ / g 5.8 5.6 5.1 10.8 Dry Embossed Paper MDT gf / 3" 785 812 822 580 (no embossing) Dry Embossed Paper CDT gf / 3" 461 501 505 344 (no embossing) Dry Embossed Paper BBW cm³ / g 11.6 9.7 8.0 / It can be seen that the tissue paper prepared by the method of the present invention can further improve the bulk compared with the existing embossing method. Specifically, compared with Comparative Example 1, the bulk is increased by 19.6%, which is equivalent to or exceeds the BBW of tissue paper produced by the TAD process with basically the same basis weight. At the same time, the strength is basically equivalent to that of the existing embossing technology, and at the same time exceeds that of tissue paper produced by the TAD process, which can meet the needs of subsequent processing and use.

[0073] Furthermore, the present invention also provides a device for applying the method of the present invention, wherein the device includes a humidifying unit 11, a clamping and conveying unit 12, an embossing unit 13 and a drying unit 14, wherein the humidifying unit 11, the clamping and conveying unit 12, the embossing unit 13 and the drying unit 14 have been explained in the above description and will not be repeated here.

[0074] Furthermore, a first conveying unit 112 is further included between the humidifying unit 11 and the clamping and conveying unit 12 for transferring the moistened paper to the clamping and conveying unit 12, and the time on the first conveying unit 112 should be less than or equal to 2 seconds.

[0075] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing household paper, characterized in that: include: S1: providing base paper and wetting the base paper to form wetted paper; S2: The moistened paper is clamped and transported for a period of 3 seconds or longer. After the process, the moisture content of the moistened paper is greater than or equal to 25%. S3: embossing the moistened paper to form an embossed wet paper; S4: drying the embossed wet paper to form dry embossed paper, wherein the moisture content of the dry embossed paper is less than or equal to 9%.

2. The preparation method according to claim 1, characterized in that In step S1, the base paper is moistened by spraying water. The water sprayed on the base paper only includes liquid water and does not contain components that increase or decrease viscosity. At the same time, the water is sprayed on the base paper surface in the form of water mist, and the particle size of the water mist droplets is 0.02mm to 0.4mm.

3. The preparation method according to claim 1, characterized in that: During the clamping and conveying process, the moistened paper is in a slight pressure process, and during the clamping and conveying process, the moistened paper undergoes at least one bending process.

4. The preparation method according to claim 3, characterized in that: The moistened paper is clamped and conveyed by a clamping and conveying unit, the clamping and conveying unit comprises an upper clamping part and a lower clamping part, a clamping area is formed between the upper clamping part and the lower clamping part, the clamping area comprises a first clamping section located upstream and a second clamping section located downstream, the first clamping section and the second clamping section are both straight-line-shaped, the second clamping section is inclined to the first clamping section, and the angle between the first clamping section and the second clamping section is 120° to 165°.

5. The preparation method according to claim 4, characterized in that: The height of the first clamping section gradually decreases from upstream to downstream, so that the moistening paper is subjected to gradually increasing pressure from upstream to downstream in the first clamping section.

6. The preparation method according to claim 4, characterized in that: The first clamping section includes an inlet end, the moistened paper includes a first wet paper entering the clamping area from the inlet end, the upper clamping part includes a plurality of upper rollers and an upper clamping belt wound on the upper rollers, the lower clamping part includes a plurality of lower rollers and a lower clamping belt wound on the lower rollers, the upper rollers include a first upper roller located in an upstream direction and a second upper roller located in a downstream direction, the lower rollers include a first lower roller located in an upstream direction and a second lower roller located in a downstream direction, the upper clamping belt includes a first front contact point connected to the first upper roller, the upper clamping belt includes a first rear contact point closest to the first lower roller, the upper clamping belt includes a front guide section between the first front contact point and the first rear contact point, the first wet paper conflicts with the front guide section at the first rear contact point, and is separated from the front guide section at the first front contact point, and the front guide section has an angle of 1° to 4° with the first wet paper.

7. The preparation method according to claim 6, characterized in that: The second clamping section comprises an outlet end, and the moistening paper comprises a second wet paper separated from the outlet end, and the second wet paper separates from the outlet end after being slightly bent.

8. The preparation method according to claim 7, characterized in that: The second lower roller is located behind the second upper roller, and the second wet paper includes a wet paper front section and a wet paper rear section located in front of the second lower roller. The wet paper front section and the wet paper rear section are not located in the same plane, and an angle of 165° to 175° is formed between the wet paper front section and the wet paper rear section.

9. The preparation method according to claim 1, characterized in that: In step S3, the moistened paper is embossed by an embossing unit, the embossing unit includes an embossing roller group, the embossing roller group includes an embossing roller and a bottom roller, the embossing roller also includes an annular groove, the annular groove and the bottom roller form an accommodating space, the clamping and conveying unit includes a transfer belt, at least a portion of the transfer belt extends from the clamping and conveying unit and passes through the accommodating space, the moistened paper moves along with the transfer belt to between the embossing roller and the bottom roller, and is formed into an embossed pattern by the embossing protrusions set in the embossing area by the embossing roller.

10. A device using the method for preparing household paper as claimed in claim 1, characterized in that: include: A humidifying unit, used for moistening the base paper to form moistened paper; A clamping and conveying unit is used to clamp and convey the moistened paper, and the clamping and conveying process is greater than or equal to 3 seconds. After the clamping and conveying, the moisture content of the moistened paper is greater than or equal to 25%; An embossing unit, comprising an embossing roller group for embossing the moistened paper to form an embossed wet paper; The drying unit dries the embossed wet paper to form dry embossed paper, and the moisture content of the dry embossed paper is less than or equal to 9%.

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