Tissue paper making machine

Abstract

The invention relates to a machine (10) for producing tissue paper, comprising a forming section (20) having a fabric (24) for dewatering and conveying a newly produced tissue paper web; an aeration-drying section (20) having at least one aeration-drying unit (32, 34); the forming section (20) has at least one aeration-drying unit (32, 34), and a Yankee section (40) having a Yankee cylinder (40), the aeration-drying section (30) comprises a TAD fabric (36) for receiving a tissue paper web from the fabric (24) of the forming section (20) and for conveying the tissue paper web in the direction of the Yankee section (40) through the at least one aeration-drying unit (32, 34), and the TAD fabric (36) is designed as a spiral-linking fabric (36), the spiral-bonded fabric does not contain any coating or the like.

Description

[0001] The invention relates to a machine for manufacturing tissue paper, the machine comprising: a forming section having a fabric for dewatering and conveying a newly produced tissue paper web; a through-air drying section having at least one through-air drying unit; and a Yankee section having a Yankee cylinder, wherein the through-air drying section comprises a TAD fabric for receiving the tissue paper web from the fabric of the forming section and for conveying the tissue paper web through the at least one through-air drying unit in the direction of the Yankee section.

[0002] Such machines (sometimes also simply referred to as TAD machines) are well known in the industry. For example, reference may be made to patent application document WO 93 / 22498 A1. In such machines, the TAD fabric is usually a woven fabric. It is woven in such a way that the front side of the tissue paper is constructed as a tissue paper product with a visible texture. Alternatively, other fabrics than woven fabrics can also be used as some kind of base fabric, which has a coating or imprint on its front side of the tissue paper to texture the tissue paper product. However, the coating or imprint or the like on the front side of the tissue paper is difficult to apply to the base fabric so that it will not fall off or deform over time. This is especially the case if the tissue paper web is conveyed on the TAD fabric through a pressure zone (for example, the pressure zone formed by a press roll and a Yankee cylinder).

[0003] Although these machines produce no inferior tissue, the market is still seeking improved properties in tissue and towel production, including softness, bulk, feel (flexibility), water absorption, and wet and dry tensile strength relative to the final paper basis weight and the number of plies (plies) in the final product. In addition, there is a growing demand among tissue producers for unique structures that can give them an advantage over the competition and differentiate them in the market, both in terms of the paper’s appearance and final functionality.

[0004] The present invention aims to solve or at least alleviate these problems. This is achieved by the technical solutions of the independent claims. The dependent claims describe advantageous improved embodiments of the present invention.

[0005] These technical problems are solved or at least alleviated, inter alia, by the above-mentioned conventional tissue papermaking machine, wherein the TAD fabric is constructed as a spiral-link fabric which does not contain any coating or the like.

[0006] The inventors have found that this "pure" spiral-link fabric is very suitable for use as a TAD fabric in a TAD machine, which is an advantage of the present invention. The spiral-link fabric provides a unique structure with excellent pocket depth to form a tissue web that exceeds conventional woven fabric structures. In addition, the spiral is an extremely stable structure in both the machine direction and the cross-machine direction, and has a higher overall strength than a woven structure. Last but not least, the spirals can be quickly linked together, making the setup and start-up of the spiral-link fabric faster and safer.

[0007] Preferably, the forming section comprises a twin-filament former having two converging fabrics forming a gap for receiving the fiber suspension ejected from the headbox. However, other known types of forming sections may be used but are less preferred. Both converging fabrics may be woven fabrics, wherein at least the fabric conveying the newly produced tissue web to the TAD fabric may be a structured fabric. Sometimes these fabrics are referred to as forming fabrics and molding fabrics.

[0008] In a preferred embodiment of the present invention, the ventilation drying section comprises two ventilation drying units, more preferably exactly two ventilation drying units, so that the tissue paper web can be dried very effectively.

[0009] Tests have shown that particularly good results are achieved if the spiral-linked fabric provides a contact area of ​​between 15% and 25% for the tissue web. To achieve such a high contact area, the tissue-facing side of the spiral-linked fabric can be ground. Additionally or alternatively, flat yarns, e.g. yarns with a flat (oval) or even substantially rectangular cross section, can also be used to form the loops of the spiral-linked fabric instead of yarns with a substantially circular cross section.

[0010] Another advantage of using a spiral-linked fabric as a TAD fabric is that a wide range of air permeability can be adjusted very easily. To this end, the spiral-linked fabric can include a filling yarn inserted into the gap formed by the coil connection. The air permeability of a spiral-linked fabric is much higher than that of most woven fabric structures of comparable density. The number and size of the filling yarns vary, and the gap can be completely filled or partially filled. The filling yarn located in the center of the paired spiral coils can be customized as a bottom surface on which the tissue paper web is formed within the coil spacing. This can be done with flat or round monofilaments, which can be placed in each coil or in certain combinations, such as every other coil, every third coil, etc.

[0011] In such applications, it is preferred that the spirals be produced from a heat resistant, thermally stable material. Good results are achieved if the spirals of the spiral-link fabric are produced from polyphenylene sulfide. This material is also known as polyphenylene sulfide (PPS), which is marketed under the trade name "Ryton". Alternatively, the spirals of the spiral-link fabric may be produced from polyethylene terephthalate (also known as PET). PET is preferably hydrolytically stabilized.

[0012] Depending on the final requirements of the tissue paper product, different diameters of spiral coils can be selected. In a preferred first embodiment of the present invention, the spiral of the spiral-linked fabric has a spiral coil diameter between 0.50 mm and 0.60 mm, preferably about 0.55 mm. In a preferred second embodiment of the present invention, the spiral of the spiral-linked fabric has a spiral coil diameter between 0.65 mm and 0.75 mm, preferably about 0.70 mm. And in a preferred third embodiment of the present invention, the spiral of the spiral-linked fabric has a spiral coil diameter between 0.85 mm and 0.95 mm, preferably about 0.90 mm.

[0013] The basic idea of ​​the present invention can also be expressed differently, namely the use of a spiral-linked fabric, which is used as a TAD fabric in a TAD machine for manufacturing tissue paper, wherein the spiral-linked fabric does not contain any coating or the like, and the TAD machine comprises: a forming section having a fabric for dewatering and conveying a newly produced tissue paper web; a ventilation drying section having at least one ventilation drying unit; and a Yankee section having a Yankee cylinder, wherein the ventilation drying section comprises a TAD fabric for receiving the tissue paper web from the fabric of the forming section and for conveying the tissue paper web in the direction of the Yankee section through the at least one ventilation drying unit.

[0014] The present invention or its preferred embodiment will now be described with reference to the following schematic diagram:

[0015] Figure 1 : shows a tissue papermaking machine according to the present invention;

[0016] Figure 2 : Show Figure 1 A portion of a first embodiment of a TAD fabric for use in a tissue papermaking machine is shown;

[0017] Figure 3 : Show Figure 1 A top view of a portion of a second embodiment of a TAD fabric for use in a tissue papermaking machine is shown;

[0018] Figure 4 : Show Figure 3 A partial side view of a second embodiment of a TAD fabric is shown; and

[0019] Figure 5 : Show Figure 3 and Figure 4 Simulation results of the contact area of ​​a portion of the second embodiment of the TAD fabric are shown.

[0020] Figure 1 An exemplary embodiment of a tissue papermaking machine 10 according to the invention is shown. The tissue papermaking machine comprises a forming section 20, a through-air drying section 30 and a Yankee section 40. In addition, a winding section 50 for winding the final tissue web can be arranged after the Yankee section 40. Further transformation of the tissue web can be done offline on a separate machine.

[0021] In the present embodiment, the forming section 20 is designed as a so-called twin-wire former. It comprises two fabrics 22 and 24, wherein the first fabric 22 is sometimes also referred to as a forming fabric and the second fabric 24 is referred to as a molding fabric. Typically, these fabrics 22 and 24 are woven fabrics consisting of intersecting warp and weft yarns. When the tissue paper machine 10 is in operation, the first fabric 22 is in the Figure 1 The first fabric 22 moves counterclockwise in the middle, while the second fabric 24 moves clockwise. The two fabrics 22 and 24 form a converging gap into which the fiber suspension is injected through the headbox 26. The newly produced tissue paper web is further dewatered on the second fabric 24. At the same time, the newly produced tissue paper web is transported on the second fabric 24 toward the through-air drying section 30.

[0022] In this exemplary embodiment, the air drying section 30 includes two air drying units, namely a first air drying unit 32 and a second air drying unit 34. Each of the two air drying units 32 and 34 includes an air drying cylinder and an air drying hood, and dries the tissue web by blowing hot air therein. The tissue web from the forming section 20 is transferred from the second fabric 24 to the TAD fabric 36, which will be referred to below. Figure 2-5 In use, the TAD fabric 36 is Figure 1 The tissue web is conveyed through two through-air drying devices 32 and 34 toward the Yankee section 40 by moving in a counterclockwise direction. The Yankee section 40 includes a Yankee cylinder and a Yankee sleeve. In this example, the TAD fabric 36 transfers the tissue paper directly onto the outer surface of the Yankee cylinder 42. Thus, a nip is formed between the press roll within the loop of the TAD fabric 36 and the Yankee cylinder 42. The press roll may be a roll that provides an extended nip, such as a shoe-type press roll.

[0023] In the Yankee section 40, the tissue web is further dried in a known manner and then rolled up in a winder section 50 for further transport and / or conversion.

[0024] Figure 2 Show Figure 1A portion of a first embodiment of a TAD fabric 36 for use in a tissue papermaking machine 10 of the present invention. According to the present invention, the TAD fabric 36 is a spirally linked fabric without any coating or the like. The term "like" should be understood in a broad sense, also including staple fibers, printing, lamination, etc. The TAD fabric 36 is basically composed of yarns in the form of spiral coils 37 and substantially straight hanks 38 (hinge yarns) connecting the spiral coils 37. Figure 2 In the first embodiment of the TAD fabric 36, the TAD fabric 36 further includes a filling yarn 39. The filling yarn 39 is inserted into the gaps formed by the spiral coils 37. The use of such a filling yarn 39 can adjust the air permeability of the TAD fabric 36 to a given value. In the present embodiment, the filling yarn 39 is substantially flat, located at the center of each gap, and substantially fills the entire gap. However, different quantities and sizes may also be used, and the filling yarn may also partially fill the gap.

[0025] Figure 3 to Figure 4 Show Figure 1 A portion of a second embodiment of a TAD fabric 36 for use in a tissue papermaking machine 10, wherein: Figure 3 This is its top view. Figure 4 is its side view, Figure 5 Show Figure 3 and Figure 4 The following describes only the contact area of ​​a portion of the second embodiment of the TAD fabric 36. Figure 2 The first embodiment of Figure 3 to Figure 4 The same or similar elements have the same reference symbols and reference is made to the above description.

[0026] The main difference between the two embodiments is that the second embodiment does not include any filling yarn. Therefore, the air permeability of the second embodiment is quite high. Figure 5 It can be concluded from the simulation shown that the front side of the tissue paper, i.e. Figure 5 On the upper side of the middle, the contact area is about 19%. In addition, in this embodiment, the potential caliper amount is 1.97mm.

[0027] Reference numerals list

[0028] 10 Cotton paper making machine

[0029] 20 Forming Department

[0030] 22. First fabric (forming fabric)

[0031] 24 Second fabric (molded fabric)

[0032] 26 headbox

[0033] 30 Ventilation and drying section

[0034] 32. First ventilation and drying unit

[0035] 34 Second ventilation and drying unit

[0036] 36 TAD Fabric

[0037] 37 Helical Coil

[0038] 38 skeins

[0039] 39 Filling Yarn

[0040] 40 Yang Kebu

[0041] 42 Yankee cylinder

[0042] 44 Yang Ketao

[0043] 50 Winding unit

Claims

1. A machine (10) for making tissue paper, the machine comprising: - a forming section (20) having a fabric (24) for dewatering and conveying the newly produced tissue web; - a ventilation and drying section (20) having at least one ventilation and drying unit (32, 34); and - a Yankee section (40) having a Yankee cylinder (40), The ventilation and drying section (30) comprises a TAD fabric (36) for receiving a tissue paper web from the fabric (24) of the forming section (20) and for conveying the tissue paper web through the at least one ventilation and drying unit (32, 34) in the direction of the Yankee section (40), wherein the TAD fabric (36) is constructed as a spirally linked fabric (36) which does not contain any coating or the like.

2. The tissue papermaking machine (10) according to claim 1, characterized in that The forming section (20) comprises a twin-filament former having two converging fabrics (22, 24) forming a gap for receiving a fiber suspension ejected from a headbox (26).

3. The tissue papermaking machine (10) according to claim 1 or 2, characterized in that The ventilation and drying section (30) comprises two ventilation and drying units (32, 34).

4. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral-link fabric (36) provides between 15% and 25% contact area to the tissue web.

5. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral-linked fabric (36) includes a filling yarn (39) inserted into gaps formed by the linking of the loops (37).

6. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral coils (37) of the spiral-linked fabric (36) are made of polyphenylene sulfide or polyethylene butylene terephthalate.

7. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral coil (37) of the spiral-linked fabric (36) has a spiral coil diameter between 0.50 mm and 0.60 mm, preferably about 0.55 mm.

8. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral coils of the spiral-link fabric (36) have a spiral coil diameter between 0.65 mm and 0.75 mm, preferably about 0.70 mm.

9. A tissue paper machine (10) according to any one of the preceding claims, characterised in that The spiral coil (37) of the spiral-linked fabric (36) has a spiral coil diameter between 0.85 mm and 0.95 mm, preferably about 0.90 mm.

10. Use of a spiral-linked fabric (36) as a TAD fabric in a TAD machine for making tissue paper, the spiral-linked fabric (36) not containing any coating or the like, the TAD machine comprising: - a forming section (20) having a fabric (24) for dewatering and conveying the newly produced tissue web; - a ventilation and drying section (20) having at least one ventilation and drying unit (32, 34); and - a Yankee section (40) having a Yankee cylinder (40), The ventilation drying section (30) comprises a TAD fabric (36) for receiving a tissue paper web from the fabric (24) of the forming section (20) and for conveying the tissue paper web through the at least one ventilation drying unit (32, 34) in the direction of the Yankee section (40).

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