WO2008004622A1

WO2008004622A1 - Papermaking felt

Info

Publication number: WO2008004622A1
Application number: PCT/JP2007/063462
Authority: WO
Inventors: Yoshiaki Ito
Original assignee: Ichikawa Co., Ltd.
Priority date: 2006-07-06
Filing date: 2007-07-05
Publication date: 2008-01-10
Also published as: JP2008013878A; KR20090034832A; CN101484635A; EP2042653A1; JP4958491B2; CA2656889A1

Abstract

A papermaking felt (100) obtained by: superposing two or more bases of the same or different kinds together with a layer of bat fibers comprising core-sheath composite fibers, the bat-fiber layer being disposed on one or each side of each base; and uniting them by entangling through needling. At least one of the bases includes, as warps or wefts, a soft twist yarn comprising core-sheath composite fibers. This felt attains satisfactory water removal and excellent wet-web smoothness. It is satisfactory in compressability by pressing, recovery, and retention of recovery and, in particular, has excellent unsusceptibility to fiber shedding. It is hence suitable for use in high-speed papermaking machines.

Description

Specification

Papermaking felt Technical Field

[0001] The present invention relates to a papermaking belt (hereinafter, sometimes simply referred to as "flut") used in a papermaking machine. More specifically, the present invention relates to a papermaking felt that is pressurized by a press section of a papermaking machine and serves to squeeze moisture from a wet papersheet.

Background art

In the press part of the papermaking process, a papermaking felt that squeezes moisture from the wet paper is used. In other words, in a paper machine that also removes moisture from the wet paper, water is dehydrated continuously from the wet paper by three parts: molding, pressing, and drying. Each of these parts uses paper making tools that support the dewatering function.

FIG. 5 is a schematic view of a press device.

The press apparatus shown in FIG. 5 includes a pair of press rolls Pa and Pa and a pair of felts 11a and 11a that sandwich the wet paper web Wa. By applying pressure to the felts 11a and 11a and the wet paper Wa in the pressurizing part by the press rolls Pa and Pa, moisture is squeezed out of the wet paper Wa and absorbed by the felt 11a and 11a.

The moisture absorbed by the felt 11a and 11a is felt felt box FS, respectively.

B is removed by suction. Moisture that has not been absorbed by the felt in the press is discharged as splash SP in the tangential direction of the bottom press roll Pa at the press exit.

[0004] The felt has a plurality of basic functions, and each function needs to play its role. These functions include water squeezing ability to squeeze water, smoothness to increase the smoothness of wet paper, and wet paper transport to transport wet paper. Felt has all these functions in balance! /, Must! /.

[0005] Among these functions of the felt, in the function of squeezing wet paper strength water (water squeezing), when the wet paper and the felt pass between a pair of press rolls, the wet paper and the felt are added. Compressed in the thickness direction by pressure. Wet paper strength The squeezed water moves to the felt. Then, the water in the felt is sucked by the force of the felt back side by pressure or sucked by the paper machine suction box and discharged out of the felt system. For this reason, with regard to the felt, importance is attached to the water permeability of the felt and the function of recovering the felt compressed by the pressurization (compression recovery and its sustainability).

In addition, when the felt passes through the suction box, frictional wear progresses and the fibers may fall off. Therefore, it is important for felt to maintain these functions from the beginning of use, including the function of hair loss resistance.

[0006] In addition, in papermaking felts, the function (smoothness) of improving wet paper smoothness by being compressed when pressed to make the felt smooth is also regarded as important!

As a felt having such a function, for example, JP 08-302584 A discloses a felt including fibers having a core-sheath structure made of a two-component material. In this felt, a two-component material consisting of a sheath material with a low melting point and a core material with a high melting point is used for the yarn of the base fabric and the fibers of the bat layer. The sheath material having a low melting point is softened by the heat curing treatment of the felt, and a matrix is formed in the bat fiber layer. As a result, the dewatering performance of the felt can be improved and the compression resistance can be increased.

FIG. 1 is a cross-sectional view of a conventional general papermaking felt. Figure 1 illustrates the general felt configuration.

The papermaking felt 10 is formed in an endless shape. The felt 10 is composed of a base 20 that has a force such as a woven fabric and a bat fiber layer 30 that is entangled and integrated with the base 20 by a one-dollar punch.

The substrate 20 is configured to develop the mechanical strength of the felt 10. For the substrate 20 in FIG. 1, a woven fabric obtained by weaving warp (MD yarn) 22 and weft (CD yarn) 21 is used.

[0008] By the way, the environment for the use of papermaking felt has become increasingly severe in recent years as the operating speed of the papermaking machine has increased due to the improvement in paper productivity and the pressure in the press section has increased. . In other words, as a recent trend in papermaking technology, high-speed papermaking machines are progressing to improve productivity. Further, in the press part, high pressurization by a roll or a shrew press is progressing. Under this high pressure, the compression recoverability of the papermaking felt deteriorates at an early stage, resulting in a problem that the water permeability is poor and the squeezing performance is significantly reduced.

In addition, the high speed of the paper machine causes the bat fibers that make up the felt to be rubbed and worn out, causing hair removal. As a result, various problems such as non-uniform paper quality and insufficient printability may occur.

Therefore, the basic performance required for felt is to maintain water squeezing, smoothness, and hair loss resistance. In particular, the latest high-speed paper machines are required to have a higher level of performance with regard to the sustainability of these squeezing properties, smoothness and hair removal resistance.

[0009] Various means have been proposed as means for solving this problem, such as a conventional technique. For example, a proposal has been made to increase the ratio of the base portion and maintain the water permeability of the felt. A method for increasing the ratio of the substrate portion is disclosed in Japanese Patent Application Laid-Open No. 2003-13385. In this method, a plurality of endless woven fabrics such as bag weaves (or endless woven fabrics joined together by joining them together) are overlapped. After the bat fibers are laminated, they are intertwined by needling.

On the other hand, Japanese Patent Application Laid-Open No. 08-302584 proposes a felt using a two-component material for the batt layer. In this case, the felt is heat-treated to soften the low-melting-point material of the two-component material and penetrate into the cross section of the bat fiber or the base fabric. The two-component material then cures to form a matrix, and the base fabric is strengthened to exhibit compression resistance.

Patent Document 1: Japanese Patent Application Laid-Open No. 08-302584

Patent Document 2: Japanese Patent Laid-Open No. 2003-13385

However, as disclosed in Japanese Patent Application Laid-Open Nos. 08-302584 and 2003-13385, the felt has a problem that it is easily subjected to repeated compression fatigue by a press device.

In addition, the felt described in Japanese Patent Application Laid-Open No. 08-302584 is inferior in smoothness and water squeezability as a result of being less compressed by pressurization.

[0012] The present invention has been made in order to solve such a problem, and only has good water squeezability. Another object of the present invention is to provide a papermaking felt that is excellent in wet paper smoothness, hair removal resistance and durability, and in particular, has excellent hair removal resistance suitable for a high speed paper machine.

Disclosure of the invention

In the present invention, as a result of studying the felt structure suitable for these purposes, two or more substrates (first substrate and second substrate) are used. At least one of the plurality of substrates is composed of warp yarns or weft yarns having a twisted twisting force including a core-sheath composite fiber.

This yarn tends to be flat. Further, the gap between the yarns is closed by melting of the low melting point component of the bat fiber including the core-sheath composite fiber and the low melting point component of the yarn. It was found that the above-mentioned purpose can be achieved by configuring the felt in this way.

Here, the term “gap gap” means the gap between the warp or weft yarn arrangement (gap between yarns) and the gap inside the yarn (gap between the single yarn constituting the twisted yarn and the single yarn). To do.

[0014] That is, the papermaking felt according to the present invention has a bat fiber including a core-sheath composite fiber laminated on one side or both sides of two or more substrates of the same or different types, and is entangled integrally by needling. I'm jealous.

At least one of the plurality of substrates is composed of a twisted yarn composed of a sweet-twisted warp (MD yarn) or a weft (CD yarn) including a core-sheath composite fiber.

[0015] Preferably, in the papermaking felt of the present invention, the substrate is composed of warps and wefts in an end shape. The substrate is laminated by winding a plurality of times to form a laminated substrate. The sweet-twisted warp (MD yarn) or weft (CD yarn) containing the core-sheath composite fiber of the laminated substrate is flat. Further, the gap between the yarns is blocked by melting of the low melting point component of the bat fiber including the core-sheath composite fiber and the low melting point component of the yarn.

[0016] Preferably, in the papermaking felt of the present invention, the substrate is a multi-woven fabric woven with a double weaving or more. The warp yarn (MD yarn) or the weft yarn (CD yarn) including the core-sheath composite fiber constituting the multi-woven fabric is flat. Further, the gap between the yarns is closed by melting of the low melting point component of the bat fiber including the core-sheath composite fiber and the low melting point component of the yarn.

In the present invention, one of the warp and the weft forming the base is a yarn containing a core-sheath composite fiber, and a twisted yarn (twisted with a filament having a fineness of 50 to 400 dtex ( Preferably, it is a twisted yarn of sweet twist.

[0018] Further, the substrate of the present invention is composed of a yarn having a specific fineness, so that the yarn becomes flat. In order to further enhance this effect, it is effective to use a sweet twisted yarn. In this sweet-twisted yarn, the number of twists of the twisted yarn is in the range of 30 to LOO times per lm, and the ratio of the lower twist is in the range of 1.2 to 1.4 in the lower / upper direction.

By making such a twisted yarn a sweet twist, the twisted yarn is easily flattened when the substrate is constructed, and thus has a function of improving the smoothness of the substrate.

[0019] Here, if the number of times the lower twist (and / or the upper twist) of the twisted yarn is out of the range of 30 to: LOO times / m, the twisted yarn becomes a strong twisted yarn and becomes flat when the substrate is constituted. It is difficult to achieve the effect of the present invention to obtain a twisted yarn.

When the ratio of the number of the lower twists / the number of the upper twists is in the range of 1.2 to 1.4, the twisted yarn is easily flattened when the substrate is constructed, and becomes a stable sweet twisted yarn having no knots and yarn variations in the twisted yarn. However, if the ratio of the number of the lower twists / the number of the upper twists is out of the range of 1.2 to 1.4, the twisted yarns are twisted in the base when the base is constructed, and the twists are not evenly flattened.

[0020] The sweet-twisted yarn (twisted yarn) of the present invention is a bundle of filaments including core-sheath composite fibers, and the ratio of the filaments of the core-sheath composite fibers is in the range of 25% to 75% with respect to the total number of filaments of the twisted yarn. It is preferable that

The first reason is that when the ratio of the filament of the core-sheath composite fiber is 25% or less, the fixation with the vat fiber containing the core-sheath composite fiber is poor due to melting, and the function of keeping the twisted yarn flat is poor. Because it becomes.

The second reason is that when the ratio of the filament of the core-sheath composite fiber exceeds 75%, the yarn becomes too flat, and the anchor is strongly fixed by melting with the bat fiber containing the core-sheath composite fiber. This is the force that makes the felt unsqueezable.

[0021] The sweet-twisted yarn of the present invention may be a spun yarn having a staple fiber strength of 6 to 50 dtex and containing a core-sheath composite fiber! /.

[0022] In the felt of the present invention, the sweet-twisted yarn of the base becomes flat and the gap between the yarns is closed, so that wet paper smoothness is excellent in hair removal resistance. In order to make the base yarn easy to be flat, a base composed of warps and wefts in an end shape is used. Thus, the substrate is laminated by winding the substrate a plurality of times to constitute a laminated substrate. In this case, the upper layer sweet twisted yarns are arranged so as to fill the gap between the lower layer twisted yarns, so that the layer of the laminated substrate becomes dense.

Then, the bat fiber including the core-sheath composite fiber is intertwined with the laminated substrate by needling. Further, the low melting point component of the bat fiber of the core-sheath composite fiber and the low melting point component of the yarn are melted by the action of heat, so that the gap between the yarns of the laminated substrate is easily closed.

[0023] In order to make the sweet twisted yarn flat and easily close the gap, there is another embodiment. In another embodiment, the substrate is a multi-woven fabric woven with a double weave or more. As a result, the sweet twisted yarn constituting the multi-woven fabric becomes flat.

In addition, as in the case of the end laminated substrate, the low melting point component of the bat fiber of the core-sheath composite fiber and the low melting point component of the yarn are melted, so that the gap between the sweet woven yarns of the multi-woven fabric is easy. Blocked.

[0024] In order to make it easier for the sweet-twisted yarn to become a flat yarn when constituting the base, and to easily close the gap between the sweet-twisted yarns, the warp (MD yarn) and the weft (CD) The number of entanglement points of thread is small! / Is more effective.

For this purpose, weaving solvent-soluble filaments (especially water-soluble filaments) on the warp (MD yarn) or weft (CD yarn) constituting the substrate. Next, batt fibers are planted on the woven fabric thus woven using a needle punch technique. Thereafter, by dissolving and removing the single yarn of the woven fabric, the yarn gap can be more easily blocked.

[0025] As a raw material for the solvent-soluble filament, polybulal alcohol, acrylic, polyester and the like can be used. Particularly, water-soluble polybulal alcohol is preferable. Except for the case of using the solvent-soluble filament, nylon or polyester is used as the twisted yarn or single yarn constituting the substrate. In particular, nylon is preferred because of its excellent strength and durability!

[0026] Further, the felt of the present invention is entangled integrally with the substrate by dripping a bat fiber containing a core-sheath composite fiber on one surface or both surfaces of the substrate. Therefore, according to the present invention, the low melting point component of the core-sheath composite fiber in the bat fiber and the low melting point component of the base yarn containing the core-sheath composite fiber can be fixed by melting under the action of heat. . As a result, the base and bat fiber The bond strength with the vascular layer is increased, and the felt has excellent hair removal resistance.

In particular, it is preferable to use a bat fiber containing a core-sheath composite fiber for the bat layer on the surface side (wet paper placement side) of the substrate.

[0027] The content of the core-sheath composite fiber in the surface-side batt layer of the substrate is preferably 25% to 75%. The first reason is that when the content of the core-sheath composite fiber is 25% or less, the bonding strength between the base and the batt fiber layer is weak and the hair removal resistance is poor. The second reason is that when the content ratio of the core-sheath composite fiber is 75% or more, the compression recovery property of the batt fiber layer is poor and the felt is inferior in water squeezing.

Note that the surface-side batt layer of the substrate may have a multilayer structure, and the content of the core-sheath composite fiber may be increased stepwise toward the surface of the substrate toward the wet paper.

[0028] Nylon 6, nylon 66, nylon 46, nylon 610, and nylon 612 are preferable as the nylon used for the core component of the core-sheath composite fiber of the present invention. For details, ε-force prolactam polymerization (nylon 6), hexamethylene diamine 'adipate polycondensation (nylon 66), 1,4-diaminobutane' adipate polycondensation (nylon 46), hexamedium Tylenediamine • Sebacinate polycondensation (nylon 610), hexamethylene diamine 'dodecanedioic acid polycondensation (nylon 612), and nylon obtained by polycondensation of nylon salts are preferred. In particular, aliphatic nylon having a melting point of 200 ° C. or higher by DSC (differential scanning calorimeter) can be mentioned.

[0029] The nylon used for the sheath component of the core-sheath composite fiber of the present invention is preferably nylon having a lower melting point than the core component. As this nylon, there are binary copolymer nylon and ternary copolymer nylon.

Examples of the binary copolymer nylon include nylon 6Z12, nylon 6Z610, nylon 66Z6, nylon 66Z12, nylon 66/610, and the like. Examples of the ternary copolymer nylon include nylon 6Z66Z12 and nylon 6Z66Z610. It is well known that these copolymer nylons vary in melting point depending on the composition (% by weight of copolymer component), but copolymer nylons that can be used in the present invention have a melting point of 180 ° C or less. Limited to those.

[0030] Preferably, in the papermaking felt, at least one of the laminated substrates includes a core-sheath composite fiber. Made of sweet twisted yarn. The yarn becomes flat when it constitutes the substrate, and the gap between the yarn is closed by melting the low melting point component of the bat fiber including the core-sheath composite fiber and the low melting point component of the yarn. It is configured. As a result, the papermaking felt is excellent in water squeezing, wet paper smoothness and hair removal resistance.

[0031] Since the present invention is configured as described above, a felt excellent in compression recovery and hair removal resistance can be obtained. When this felt is used as a felt for papermaking, the compression ratio and the recovery ratio due to pressurization by a roll or a shoe press in the papermaking process are excellent.

Therefore, the felt of the present invention does not lose the wet paper smoothness, the hair removal is suppressed, and the squeezing force and the high squeezing force are maintained for a long time. In addition, this felt can exhibit high performance to cope with the high speed of paper machines in recent years and the high pressure of the press section.

Brief Description of Drawings

[0032] FIG. 1 is a cross-sectional view of a conventional general paper-making sheet.

FIG. 2 is a cross-sectional view of the papermaking felts of Examples 1 to 4 that are useful in the present invention.

FIG. 3 is a sectional view of a papermaking felt according to Comparative Example 1.

FIG. 4 is an experimental apparatus according to the present invention.

FIG. 5 is a schematic view of a press device.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view of a papermaking felt that is useful in an embodiment of the present invention.

As shown in FIG. 2, a papermaking felt 100 according to the present invention includes a base layer 200 and a batt fiber layer 300. The bat fiber layer 300 is formed by intertwining the bat fiber (stable fiber) with the base layer 200 with one dollar punch.

The substrate layer 200 is formed by laminating two substrates (that is, a first substrate 210 and a second substrate 220). In the substrate layer 200, one first substrate 210 is a material for imparting the mechanical strength of the felt 100. The material of the first substrate 210 is not particularly limited as long as sufficient strength can be obtained, and various materials can be used. For example, a woven fabric obtained by weaving warp yarn (MD yarn) 212 and weft yarn (CD yarn) 211 can be used for the first base 210 weft. In the felt 100 shown in FIG. 2, different types of the first base 210 and the second base 220 are laminated, but the same kind may be used as long as the second base 220 satisfies the requirements of the present invention. .

[0034] As a modification, a woven fabric having a width narrower than the felt 100 to be completed may be formed of warp (MD yarn) and weft (CD yarn). In this case, after that, this woven fabric is wound in a spiral, and what is obtained by joining the edges of adjacent woven fabrics is used as the first substrate 210.

Furthermore, as another modification, it is obtained by winding a base body having warps (MD yarns) and wefts (CD yarns) having the same width as the width of the to-be-completed foot 100 on the same axis. The resulting substrate may be used as the first substrate 210.

Furthermore, as another modification example, a substrate obtained by fixing warp (MD yarn) with an adhesive, warp (MD yarn) and weft (CD yarn) is not woven, in addition to woven fabric. Alternatively, a substrate having a structure simply stacked on each other may be used as the first substrate 210.

In the present invention, in addition to the first substrate 210, another second substrate 220 is stacked to form the entire substrate layer 200. The second substrate 220 is a woven fabric woven by a combination of warp (MD yarn) 222 and weft (CD yarn) 221.

That is, one of the warp yarn 222 and the weft yarn 221 is a sweet twisted yarn including a core-sheath composite fiber composed of a filament having a fineness in the range of 50 to 400 dtex. The other of warp 222 and weft 221 is a woven fabric woven with filaments in the range of 50 to 600 dtex or solvent-soluble filaments.

In the felt 100 shown in FIG. 2, bat fibers are intertwined and integrated on both surfaces of the base layer 200 by a one-dollar punch. A batt fiber layer 300 containing core-sheath composite fibers is formed on the surface side (wet paper placement side) batt layer of the second substrate 220. As a result, the gap between the yarns is easily blocked by melting of the low melting point component of the bat fiber including the core-sheath composite fiber and the low melting point component of the yarn.

In the present invention, the low melting point component (sheath component) of the core-sheath composite fiber (stable fiber) included in the batt fiber layer 300 and the core included in the sweet-twisted yarn during the heat treatment in the felt manufacturing process The low melting point component (sheath component) of the sheath composite fiber (filament) can be melted and joined.

Example Hereinafter, the present invention will be specifically described with reference to a plurality of examples.

In each example, the second substrate having the features of the present invention on the first substrate 210.

220 (or the second substrate 230, 240, or 250) is laminated to form the entire substrate layer 200. In all the examples, a substrate having the following configuration is used for the first substrate 210.

[0039] (Example 1)

'Configuration of first substrate 210:

(1) MD yarn and CD yarn: The following twisted yarn was commonly used for both MD yarn and CD yarn.

(2) Twisting condition: “2/2/220”

However, the display format of the twisted yarn in “” represents “(number of lower twisted yarn bundles at the time of upper twist) / (number of single yarn bundles at the time of lower twist) / (single yarn fineness = dtex)”.

(3) Bottom twist: S direction 250 times / m

(4) Upper twist: Z direction 160 times / m

Both lower twist and upper twist are 150 times / m or more, and belong to strong twisted yarn. The “S direction” means that the twisted line on the yarn surface is lowered to the right, and the “Z direction” means that the twisted line on the yarn surface is lowered to the left.

(5) Twist ratio (bottom / top): 1.56

(6) Weaving:

MD yarn: 120 yarns / 5cm, CD yarn: 40 yarns / 5cm, 3/1, 1/3 bag weft warp double weave first substrate (woven fabric) 210 was woven.

As shown in FIG. 2, a felt 100 in which a batt fiber layer 300 is laminated on a substrate layer 200 obtained by laminating a second substrate 220 on a first substrate 210 was produced.

'Configuration of second substrate 220:

(1) MD yarn: The following twisted yarn was used.

(a) Twisting condition: “2/2/220”

(b) Filament ratio of core-sheath composite fiber: One filament (25%) is included in the twisted yarn.

(c) Lower twist: 42 times / m in S direction

(d) Upper twist: Z direction 30 times / m (e) Twist ratio (bottom / top): 1.40

(2) CD yarn: single yarn (diameter 330dtex)

(3) Weaving:

MD yarn: 40 pieces / 5cm, CD yarn: 34 pieces / 5cm, a 2/1 base fabric (woven fabric) 220 of 3/1 flat bag weave was woven.

(4) Formation of vat fiber layer 300:

A batt fiber layer 300 including a core-sheath composite fiber was formed on the upper surface of the second substrate 220. The core-sheath composite fiber content is 25%.

[0041] (Example 2)

As a second substrate, the following substrate 230 was laminated instead of the substrate 220 in Example 1, and the felt 100 of Example 2 was produced. That is, in FIG. 2, a second substrate 230 is laminated instead of the substrate 220.

'Configuration of second substrate 230:

(1) MD yarn: The following twisted yarn was used.

(a) Twisting condition: “2/2/220”

(b) Ratio of filament of core-sheath composite fiber: 2 filaments (50%) are included in the twisted yarn.

(c) Lower twist: 42 times / m in S direction

(d) Upper twist: Z direction 30 times / m

(e) Twist ratio (bottom / top): 1.40

(2) CD yarn: single yarn (diameter 330dtex)

(3) Weaving:

MD yarn: 40 pieces / 5cm, CD yarn: 34 pieces / 5cm, weaving a 3/1 flat single-ended woven fabric and then laminating it twice to form a second substrate with a laminated structure (Woven fabric) 230 was constructed.

(4) Formation of vat fiber layer 300: Same as Example 1.

[Example 3]

As a second substrate, the following substrate 240 was laminated instead of the substrate 220 in Example 1, and the felt 100 of Example 3 was produced. That is, in FIG. 2, the second substrate 240 is laminated instead of the substrate 220. 'Configuration of second substrate 240:

(1) MD yarn: The following twisted yarn was used.

(a) Twisting condition: “2/2/220”

(c) Bottom twist: S direction 70 times / m

(d) Upper twist: Z direction 50 times / m

(e) Twist ratio (bottom / top): 1.40

(2) CD yarn: single yarn (diameter 330dtex)

(3) Weaving:

MD yarn: 40 pieces / 5cm, CD yarn: 34 pieces / 5cm, weaving a 3/1 flat single-ended woven fabric and then laminating it twice to form a second substrate with a laminated structure (Woven fabric) 240 was constructed.

(4) Formation of vat fiber layer 300:

A batt fiber layer 300 including a core-sheath composite fiber was formed on the upper surface of the second substrate 240. The content of core-sheath composite fiber is 50%.

(Example 4)

As a second substrate, the following substrate 250 was laminated instead of the substrate 220 in Example 1 to produce the felt 100 of Example 4. That is, in FIG. 2, a second substrate 250 is laminated instead of the substrate 220.

'Configuration of second substrate 250:

(1) MD yarn: The following twisted yarn was used.

(a) Twisting condition: “2/2/220”

(b) Ratio of filament of core-sheath composite fiber: 3 filaments (75%) are included in the twisted yarn.

(c) Lower twist: S direction 120 times / m

(d) Upper twist: Z direction 100 times / m

(e) Twist ratio (bottom / top): 1.20

(2) CD yarn: 400dtex polybulu alcohol alcohol (water-soluble) filament.

(3) Weaving:

MD yarn: 90 / 5cm, CD yarn: 30/5 / 5cm, 3/1, 1/3 bag weft double weave Body (woven fabric) 250 was woven.

(4) Formation of vat fiber layer 300:

A batt fiber layer 300 including a core-sheath composite fiber was formed on the upper surface of the second substrate 250. The content of core-sheath composite fiber is 75%.

(5) Hot water scouring:

After the batt fiber layer 300 is formed, the CD yarn is dissolved by immersing in warm water at 40 ° C for 30 minutes as warm water scouring. Next, a base body 250 made of only MD yarns was formed on the first base body 210.

[0044] (Comparative Example 1)

FIG. 3 is a cross-sectional view of a papermaking felt 100a according to Comparative Example 1.

As shown in FIG. 3, in the felt 100a of Comparative Example 1, a base body layer 260 is formed by laminating a base body 210 having the same configuration as that of the first base body 210 on the first base body 210. Then, the same batt fiber layer 300 as in Example 1 is laminated on the base layer 260.

[0045] Each of the felts prepared in Examples 1 to 4 and Comparative Example 1 was circulated between a pair of rolls at a cloth speed of 2 m / min, and heat-treated while applying hot air of 180 ° C. Further, a felt for papermaking was prepared by bringing a hot press roll having a surface temperature of 160 ° C. into contact with the bat layer on the surface side of the felt.

With respect to the examples and comparative examples, the same amount (basis weight: g / m ² ) of the vat fiber layer 300 of all felts was prepared, and the paper smoothness index, compression recovery property, compression speed of these papermaking felts were prepared. Persistence of resilience and hair loss resistance were evaluated by the following methods.

[0046] (1) Paper smoothness index: Based on JIS B061-1982 (“Surface roughness”), the reciprocal of the numerical value obtained from the dispersion of the distance between adjacent peaks and valleys of the surface irregularities of the papermaking felt. is there. The higher the paper smoothness index, the smaller the roughness of the uneven distance, and the higher the smoothness. (2) Compression recovery performance, sustained performance:

Felt 100 and 100a were passed through the experimental apparatus shown in Fig. 4. The thickness of felt 100, 100a was measured with a sensor at each stage of initial non-pressurization, compression with a press tool, and after pressure release. By calculating the compression rate and recovery rate of felt 100, 100a using the following equations, the compression recovery performance of felt 100, 100a and its sustainability were evaluated. Compression rate (%) = (Flt thickness during compression Z Flt thickness without initial pressure) X 100 Recovery rate (%) = (Felt thickness immediately after pressure release Z Felt thickness during compression) ) X loo

[0047] The experimental apparatus includes a pair of press rolls PR, PR, a plurality of guide rolls GR that support the felts 100, 100a with a certain tension, and a first sensor and a second sensor, not shown. have.

The first sensor measures the thickness of the felt 100, 100a when pressed by a pair of press rolls PR, PR. The second sensor measures the thickness of the felt 100, 100a immediately after releasing the pressure by the pair of press rolls PR, PR.

The experimental equipment was driven for 120 hours at a press pressure of 100 kg / cm and a felt drive speed of 1,000 m / min.

[0048] From the values of the compression rate and the recovery rate obtained by the above measurement, the sustainability of the compression recovery properties of the felts 100 and 100a in each Example and Comparative Example 1 was evaluated, and this was evaluated as a relative score. expressed.

Here, the numerical value of Example 1 was set to “3”. On the basis of this score, the score was “good” if it was higher than “3”, and “bad” if it was lower, and the higher the numerical value, the better the score. The results are listed in Table 1.

[0049] (3) Hair loss resistance function: A hair loss resistance experiment was performed by measuring the amount of fibers dropped from the felt using a Taber polishing tester based on JIS1023-1992.

In this testing machine, a disk-shaped test piece is placed on a rotatable turntable. A rotating roll with high resistance is brought into contact with the test piece to measure the amount of fiber falling off. In the experiment, the amount of fallen fibers (hair loss) after rotating the turntable 5,000 times was measured.

The evaluation of the amount of hair loss was expressed as a relative comparison when the amount of hair removal (the amount of shed fibers) in Comparative Example 1 was set to “100”. The results are listed in Table 1.

[0050] [Table 1]

In the papermaking felt 100 of the present invention, one of the laminated substrates also has a sweet twisting yarn strength including a core-sheath composite fiber. This yarn (twisted yarn) is flat, and the gap between the yarns is blocked by melting of the low melting point component.

Therefore, as apparent from the results in Table 1, the papermaking felt 100 of the present invention is The lubricity, compression recovery performance, and sustainability of compression recovery performance were good, and the hair removal resistance was also good.

On the other hand, the felt 100a according to the comparative example 1 has two first substrates 210 woven using the same twisted yarn for both the MD yarn and the CD yarn. The felt 10 Oa according to Comparative Example 1 was poor in all of paper smoothness, compression recovery performance, persistence of compression recovery performance, and hair removal resistance.

The embodiments of the present invention (including modifications and examples; the same applies hereinafter) have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention. Modifications and additions can be made.

In the drawings, the same reference numerals indicate the same or corresponding parts.

Industrial applicability

[0053] The papermaking felt of the present invention can be applied as a felt that is pressed by a press section of a papermaking machine to squeeze moisture from a wet paper sheet.

Claims

The scope of the claims

[1] A papermaking felt obtained by laminating bat fibers including core-sheath composite fibers on one or both surfaces of two or more substrates of the same or different types, and entangled them together by needling. The papermaking felt, wherein at least one of the plurality of substrates is composed of a twisted yarn comprising a sweet-twisted warp or a weft containing the core-sheath composite fiber.

[2] The papermaking felt according to claim 1,

The base body is composed of warps and wefts in an end shape;

The substrate is laminated by winding a plurality of times to constitute a laminated substrate,

The sweet-twisted warp or weft containing the core-sheath composite fiber of the laminated substrate is flat, and the gap between the yarns is a low melting point component of the batt fiber containing the core-sheath composite fiber and the low of the yarn. It is blocked by melting with the melting point component.

[3] The papermaking felt according to claim 1,

A multi-woven fabric in which the substrate is woven with a double weave or more;

The warp or weft containing the core-sheath composite fiber constituting the multi-woven fabric is flat, and the gap between the yarns is a low melting point component of the batt fiber containing the core-sheath composite fiber and a low Blocked by melting with melting point component!

[4] A papermaking felt according to any one of claims 1 to 3,

One of the warp yarn and the weft yarn forming the substrate is a yarn containing the core-sheath composite fiber, and is a twisted yarn twisted with a filament having a fineness of 50 to 400 dtex.

[5] The papermaking felt according to any one of claims 1 to 4, wherein the number of upper twists of the twisted yarn is in the range of 30 to 100 times per lm, and the number of lower twists / the number of upper twists The ratio is 1.2 ~ 1

It is a sweet twisted yarn in the range of .4.

[6] The papermaking felt according to any one of claims 1 to 3, wherein the warp or the weft constituting the substrate is a solvent-soluble filament.