CN116905266A - A pressing method for making highly absorbent household paper - Google Patents

Abstract

The invention discloses a pressing method for making highly absorbent household paper. The pressing method includes the following steps: A. In the press zone, the wet paper web is flattened at A and B, and part of the moisture contained in it is It is squeezed into the C position of the wet paper web, part of it is squeezed into the grid space of the forming wire (and then sucked away by the negative pressure of the vacuum press roller), and part of it is squeezed into the upper press felt, because the mesh of the forming wire Due to the lattice structure, the wet paper web cannot be compacted by pressing, so the paper web still has good bulk and water absorption. However, part of the moisture in the wet paper web can be removed through mechanical extrusion and vacuum suction, so in traditional TAD Based on the method of making highly water-absorbent household paper, this method can be used to reduce the moisture content of the wet paper web entering the drying section while still ensuring that the final product has a relatively good bulk and water absorption. Select forming wires of different structures. The pressure area ratio of the wet paper web can be changed.

Description

A pressing method for making highly absorbent household paper

Technical field

The present invention relates to the technical field of toilet paper, specifically a pressing method for making highly absorbent household paper.

Background technique

Compared with ordinary toilet paper, highly absorbent tissue has significant performance advantages, and its use effect is significantly better than ordinary tissue, mainly due to its high water absorbency and more comfortable use feeling.

Since the water absorption capacity is 1.7-2 times that of ordinary household paper, the usage based on fiber weight is greatly reduced under the same effect, which can significantly save the usage of natural fiber raw materials. Take the hand towels commonly used in general public toilets as an example. , the basis weight of ordinary hand towels is generally 38-40g/m ² . After ordinary people wash their hands, one piece of paper (area about 500cm ² ) usually cannot wipe their hands completely dry quickly. Generally, two sheets are used, and highly absorbent ( Taking paper made with TAD technology as an example, with a basis weight of 28-30g/m ² and the same area), one piece of paper towel can completely dry the paper, saving more than twice the amount of fiber. Not only hand towels, but also highly absorbent toilet paper can replace any toilet paper with better performance, such as facial tissue, kitchen paper, industrial wipes, etc. Its water-absorbing and oil-absorbing effect is obviously better than ordinary toilet paper. Due to this characteristic, it is currently new in developed countries. The proportion of highly absorbent household paper in the disposable paper project is getting higher and higher, and more and more papermaking equipment manufacturers have joined the research on the manufacturing methods of highly absorbent toilet paper.

At present, the technologies for making highly absorbent toilet paper in the world mainly include the following forms:

1. The traditional TAD method (abbreviation of "through air dryer"), which is a technology that has been used for more than half a century, is characterized by its ability to produce toilet paper with very good bulk. Its main technical feature is that it does not use press dehydration during the papermaking process. It uses a combination of TAD and a traditional dryer. When the wet paper web has a dryness of about 20%, it enters the dryer. Although this technology produces paper with better performance Excellent, but because the moisture entering the dryer is too large, the energy consumed for drying is more than twice that of traditional toilet paper, and the consumption of both electrical energy and heat energy is very large;

2. Valmet's NTT technology is different from the two aforementioned technologies that do not use pressing. The characteristic of this technology is the use of pressing. The principle is to squeeze the wet paper web with a special template tape to squeeze out the water. The wet paper web is extruded into a specific shape along the direction perpendicular to the paper web (Z-direction), and the structural characteristics of the Z-direction arrangement of fibers (increased surface area) are used to increase water absorption, similar to the principle of dry wrinkling to increase water absorption. (The essence is to increase the surface area of the paper web). The advantage of this technology is that the energy consumption of paper making is almost as small as that of ordinary toilet paper. However, it is inherently disadvantageous because the entire paper web is pressed, and the void structure between the fibers is destroyed after the paper web is pressed. The water absorbency is obviously not as good as the paper made by TAD method, so it cannot replace TAD method so far.

QRT and E-TAD technology, these two technologies have similar principles. They both press the wet paper web. Although shoe press technology is used to try to maintain the bulk of the wet paper web, the pressing principle tells us that if the fiber stack is not During compression, water will not escape by itself. Therefore, the essence of this type of technology is full-scale compression. The improvement of water absorption is not mainly due to the fiber distribution structure of the paper web, but to the twists and turns of the wet paper web itself. Such paper has a water-absorbing effect. It cannot be compared with traditional TAD (although the drying energy consumption is low).

At present, the traditional TAD method is still an irreplaceable method to ensure the quality of highly absorbent household paper. However, because it does not press (no mechanical methods are used to remove moisture), the high energy consumption problem caused by the traditional TAD method due to drying the wet paper web has always been unavoidable. The problem.

Contents of the invention

The object of the present invention is to provide a pressing method for making highly absorbent household paper, so as to solve the problems raised in the above background technology.

In order to achieve the above object, the present invention provides the following technical solution: a pressing method for making highly absorbent household paper. The pressing method includes the following steps:

A. In the pressing zone, the wet paper web is flattened at A and B. Part of the moisture contained in it is squeezed into C of the wet paper web, part of it is squeezed into the space of the forming mesh grid, and part of it is squeezed into the space of the forming mesh grid. Squeezed into upper press felt;

B. After the wet paper web comes out of the forming section, it is wrinkled by the wrinkle roller, and then shaped by the shaping vacuum box and then enters the subsequent drying equipment to complete the next step of the papermaking process.

Preferably, the wet paper web has been vacuumed before entering the nip, so that vacuum suction can no longer remove the moisture in the wet paper web, so it can no longer be dehydrated by vacuum suction. If it is still used To continue dehydration using the vacuum method, a greater degree of vacuum, a longer suction time, and a greater air volume must be used. The result will be more gain than gain, because after being squeezed, the moisture at C is significantly higher than here and enters the pressing zone. The previous moisture, so the moisture entering C and the grid space is easily sucked away by the vacuum suction force of the vacuum roller under the lower pressing felt. At the same time, changing different types of forming wires, the dewatering effect of the pressing and the exit of the forming part The structural densities of the wet paper webs will all vary.

Preferably, if a forming wire with fine mesh and dense mesh is used, more water will be squeezed out, and the dryness of the wet paper web coming out of the press nip will be higher, but the compressed area of the wet paper web will account for a large proportion. ; If you use a forming wire with thick mesh and sparse mesh, less water will be removed by pressing, but the compressed area of the wet paper web will account for a small proportion.

Preferably, the forming part includes a base plate, a ground concrete foundation, a vacuum suction box under the net, a forming net, a lower press blanket, a shaping vacuum box, subsequent drying equipment, a wrinkle roller, an upper press roller, a lower vacuum press roller, It consists of an online vacuum suction box, forming rollers, headbox, upper press felt, wet paper web, forming wire guide equipment, guide rollers, forming wire washing, tensioning and correction equipment, and the above equipment is connected to the foundation through a support frame slab, while the foundation slab is set on the concrete foundation of the ground concrete foundation.

Preferably, the forming net is arranged at the upper end of the vacuum water suction box under the net, and the vacuum water suction box above the net is arranged at the upper right side of the vacuum water suction box under the net.

Preferably, the forming roller is arranged on the upper left side of the online vacuum suction box, and the headbox is arranged on the upper right side of the forming roller.

Preferably, the lower vacuum press roller is arranged at the lower left end of the upper press roller, and the corrugating roller is arranged at the lower right side of the lower vacuum press roller.

Preferably, the shaping vacuum box is arranged below the wrinkle roller, and the subsequent drying equipment is arranged below the shaping vacuum box.

Preferably, the lower press felt passes from below the forming wire, and the upper press felt passes from above the forming wire, and at the same time, the wet paper web is in contact with the forming wire.

Compared with the prior art, the beneficial effects of the present invention are as follows:

This invention is based on the traditional TAD method for making highly absorbent household paper. This method is used to reduce the moisture of the wet paper web entering the drying section while ensuring that the final product still has a relatively good bulk and water absorbency. Although this method The pressing described in the method will reduce a certain bulk of the paper web itself, but a balance point can be found by selecting forming wires of different structures, so that while the drying consumption is significantly reduced, it is ensured that the final product still has a relatively ideal bulk ( Water absorption), since the press is a controllable and incomplete press, the wet paper web will not be compacted and still has good air permeability, so TAD (Through Air Drying) can still be used for subsequent drying.

Description of the drawings

Figure 1 is a schematic diagram of the nip structure of the present invention;

Figure 2 is a schematic structural diagram of the forming part for implementing the present invention.

In the picture: foundation board 1, ground concrete foundation 2, under-net vacuum suction box 3, forming net 4, lower press blanket 5, shaping vacuum box 6, subsequent drying equipment 7, wrinkle roller 8, upper press roller 9, lower Vacuum press roll 10, online vacuum suction box 11, forming roll 12, headbox 13, upper press felt 14, wet paper web 15.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In the description of the application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "provided with", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection. It can also be a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood on a case-by-case basis.

The basic board of this application is 1, the ground concrete foundation 2, the vacuum suction box under the net 3, the forming net 4, the lower press blanket 5, the shaping vacuum box 6, the subsequent drying equipment 7, the wrinkle roller 8, the upper press roller 9, the lower The components of the vacuum press roller 10, online vacuum suction box 11, forming roller 12, headbox 13, upper press felt 14, and wet paper web 15 are all universal standard parts or components known to those skilled in the art, and their structures and principles are This technician can learn from the technical manual or through routine experimental methods.

Please refer to Figures 1 and 2, a pressing method for making highly absorbent household paper. The pressing method includes the following steps:

A. In the pressing zone, the wet paper web 15 is flattened at A and B. Part of the moisture contained in it is squeezed into the C position of the wet paper web 15, and part of it is squeezed into the space of the grid of the forming wire 4. , part of it is squeezed into the upper press felt 14;

B. After the wet paper web 15 comes out of the forming section, it is wrinkled by the wrinkle roller 8, and then shaped by the shaping vacuum box 6 and then enters the subsequent drying equipment to complete the next step of the papermaking process.

The wet paper web 15 has been vacuumed before entering the nip, so that the vacuum suction can no longer remove the moisture in the wet paper web 15. Therefore, the vacuum suction method cannot be used to dehydrate the wet paper web 15. If the vacuum method is still used, To continue dehydration, you must use greater vacuum, longer suction time and greater air volume. The result will be more gain than loss because after being squeezed, the moisture at C is significantly higher than the moisture before entering the pressing zone. , so the moisture entering C and the grid space is easily sucked away by the vacuum suction force of the vacuum roller under the lower pressing felt 5. At the same time, changing different types of forming wires 4, the dewatering effect of the pressing and the moisture removal from the forming part The structural densities of the webs 15 will all be different.

If a forming wire 4 with fine mesh and dense mesh is used, more water will be squeezed out, and the dryness of the wet paper web 15 coming out of the press nip will be higher, but the compressed area of the wet paper web 15 will account for a large proportion. ; If you use a forming wire 4 with thick mesh and sparse mesh, less water will be removed by pressing, but the compressed area of the wet paper web 15 will account for a small proportion. If you do not use the lower press felt 5, you can not use it. Pressing down the felt 5 will make the structure simpler, but it will bring about two problems: First, the opening area of the vacuum roller is not 100% continuous (mechanically impossible), in order to make the vacuum suction act more uniformly on the The wet paper web 15 needs to be balanced with the lower press felt 5 (to avoid uneven dehydration of the wet paper web). Secondly, it can reduce the impact of water adsorbed on the surface of the forming wire 4 on the wet paper web when the wet paper web 15 is separated from the forming wire 4. 15 rewetting, thereby further improving the dryness of the wet paper web 15 exiting the forming part.

The forming section includes base plate 1, ground concrete foundation 2, under-net vacuum suction box 3, forming net 4, lower press blanket 5, shaping vacuum box 6, subsequent drying equipment 7, wrinkle roller 8, upper press roller 9, lower It consists of vacuum press roller 10, online vacuum water suction box 11, forming roller 12, headbox 13, upper press felt 14, wet paper web 15, forming wire guide equipment guide roller, forming wire washing, tensioning and correction equipment, and The above-mentioned equipment is connected to the foundation plate 1 through a supporting frame. At the same time, the foundation plate 1 is set on the concrete foundation of the ground concrete foundation 2.

The forming net 4 is arranged at the upper end of the under-net vacuum water suction box 3, and the online vacuum water suction box 11 is arranged at the upper right side of the under-net vacuum water suction box 3.

The forming roller 12 is arranged on the upper left side of the online vacuum suction box 11 , and the headbox 13 is arranged on the upper right side of the forming roller 12 .

The lower vacuum press roller 10 is arranged at the lower left end of the upper press roller 9 , and the corrugating roller 8 is arranged at the lower right side of the lower vacuum press roller 10 .

The shaping vacuum box 6 is arranged below the corrugating roller 8, and the subsequent drying equipment 7 is arranged below the shaping vacuum box 6. The subsequent drying equipment 7 can be a TAD or a traditional drying cylinder.

The lower press felt 5 passes under the forming wire 4 and the upper press felt 14 passes above the forming wire 4 while the wet paper web 15 is in contact with the forming wire 4 .

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (9)

1. A pressing method for making highly absorbent household paper, characterized in that: the pressing method includes the following steps: A. In the nip, the wet paper web (15) is flattened at A and B. Part of the moisture contained in it is squeezed into the C position of the wet paper web (15), and part of it is squeezed into the forming wire ( 4) In the space of the grid, part is squeezed into the upper pressing felt (14); B. After the wet paper web (15) comes out of the forming section, it is wrinkled by the wrinkle roller (8), and then shaped by the shaping vacuum box (6) and then enters the subsequent drying equipment to complete the next step of the papermaking process. . 2. A pressing method for making highly absorbent household paper according to claim 1, characterized in that: the wet paper web (15) has been vacuumed before entering the press zone, so that Vacuum suction can no longer remove the moisture in the wet paper web (15), so it can no longer be dehydrated by vacuum suction. If the vacuum method is used to continue dehydration, a greater vacuum degree, longer suction time and A larger air pumping volume will result in more losses than gains, because after being squeezed, the moisture at point C is significantly higher than the moisture before entering the pressing zone, so the moisture entering point C and the grid space is easy to be pressed under the felt ( 5) The vacuum suction force of the lower vacuum roller sucks away. At the same time, if different types of forming wires (4) are replaced, the water removal effect of the press and the structural density of the wet paper web (15) coming out of the forming part will be different. 3. A pressing method for making highly absorbent household paper according to claim 2, characterized in that if a forming net (4) with fine mesh and dense mesh is used, the squeezed water will The dryness of the wet paper web (15) coming out of the press nip will be higher, but the compressed area of the wet paper web (15) will account for a large proportion; if a forming wire (4) with thick mesh and sparse mesh is used, ), the water removed by pressing will be relatively small, but the compressed area of the wet paper web (15) will account for a small proportion. 4. The forming part of a paper machine designed for a pressing method for making highly absorbent household paper according to claim 1, characterized in that: the forming part includes a base plate (1) and a ground (2) , Vacuum suction box under the net (3), forming net (4), lower pressing felt (5), shaping vacuum box (6), subsequent drying equipment (7), wrinkle roller (8), upper pressing roller (9 ), lower vacuum press roll (10), online vacuum suction box (11), forming roll (12), headbox (13), upper press felt (14), wet paper web (15), forming wire guide equipment ( It consists of guide rollers), forming mesh washing, tensioning and correction equipment, and the above equipment is connected to the foundation plate (1) through the frame. At the same time, the foundation plate (1) is set on the concrete foundation of the ground concrete foundation (2) . 5. A pressing method for making highly absorbent household paper according to claim 4, characterized in that: the forming net (4) is arranged at the upper end of the vacuum water suction box (3) under the net, and on the net The vacuum water suction box (11) is arranged on the upper right side of the vacuum water suction box (3) under the net. 6. A pressing method for making highly water-absorbent household paper according to claim 4, characterized in that: the forming roller (12) is arranged on the upper left side of the online vacuum water suction box (11), and flows The pulp box (13) is arranged on the upper right side of the forming roller (12). 7. A pressing method for making highly absorbent household paper according to claim 4, characterized in that: the lower vacuum press roller (10) is arranged at the lower left end of the upper press roller (9), and The corrugating roller (8) is arranged on the lower right side of the lower vacuum press roller (10). 8. A pressing method for making highly absorbent household paper according to claim 4, characterized in that: the shaping vacuum box (6) is arranged below the wrinkle roller (8), and subsequently The drying equipment (7) is arranged below the shaping vacuum box (6). 9. A pressing method for making highly absorbent household paper according to claim 4, characterized in that: the lower pressing felt (5) passes from below the forming mesh (4), and the upper pressing felt The felt (14) passes over the forming wire (4), and at the same time, the wet paper web (15) is in contact with the forming wire (4).