JP2008013878A - Felt for making paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a felt for making paper, which can well strain water, gives excellent smoothness to wet paper, has good compression rate, recovery rate and their durability, is preferably suitable for high speed paper-making machines, and has excellent hair-falling resistance. <P>SOLUTION: This felt for making paper, which is composed by laminating sheath-core conjugated fiber-containing butt fibers to one side or both the sides of the same or different kinds of two or more substrates and then needling the laminate to integrally interlace the laminate is characterized in that at least one base body is formed of twisted yarns composed of loosely twisted warps (MD yarns) or wefts (CD yarns) containing sheath-core conjugated fibers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a papermaking felt (hereinafter simply referred to as “felt”) used in a papermaking machine. More specifically, the present invention relates to a papermaking felt that is pressed by a press section of a paper machine and functions to squeeze moisture from a wet paper sheet.

  An object of the present invention is to provide a papermaking felt that has good water squeezing and is excellent in wet paper smoothness and hair removal resistance, and in particular, a papermaking felt that is excellent in hair removal resistance suitable for a high speed paper machine.

  In the press part of the papermaking process, a papermaking felt is used to squeeze water from the wet paper. In other words, in a paper machine that removes moisture from wet paper, moisture is continuously dehydrated by three parts: molding, pressing, and drying. In each of these parts, paper making tools corresponding to the dewatering function are used.

FIG. 5 is a schematic view of a press apparatus. This press device is composed of a pair of press rolls P ′ and P ′ and a pair of felts 11 ′ and 11 ′ sandwiching a wet paper web W ′.
In the pressurizing part of the press rolls P ′ and P ′, pressure is applied to the felts 11 ′ and 11 ′ and the wet paper W ′, and water is squeezed out from the wet paper W ′ and absorbed by the felts 11 ′ and 11 ′. Is done.
The moisture absorbed by the felts 11 ′ and 11 ′ is sucked and removed by the felt suction box FSB, but the moisture that has not been absorbed by the felt by the press is splashed by the bottom side press roll P ′ at the press outlet as a splash SP. It is discharged tangentially.

  Conventionally, the basic functions of papermaking felts are to squeeze water from wet paper (water squeezing), improve the smoothness of wet paper (smoothness), and transport wet paper (wet paper transportability). As a felt, all these functions must be balanced.

  As a function of squeezing water from the wet paper in the felt function for papermaking, when passing between a pair of press rolls, the wet paper and the felt are compressed in the thickness direction, and the water squeezed from the wet paper is transferred to the felt. The water in the felt is discharged from the back side of the felt by pressurization, or is sucked out of the felt system by suction with a suction box of the paper machine. For this reason, emphasis is placed on the water permeability of the felt and the function of recovering the felt compressed by pressurization (compression recovery and its sustainability). In addition, since the frictional wear progresses as the felt passes through the suction box, and the fibers may lose hair, it is important that these functions, including the anti-hair removal function, be sustained from the beginning of use. .

Further, in papermaking felts, the function (smoothness) of increasing wet paper smoothness by being compressed during pressurization and smoothing the felt is also regarded as important.
As a felt having such a function, for example, Patent Document 1 discloses a felt including a fiber having a core-sheath structure made of a two-component material.
In this felt, a two-component material composed of a low melting point sheath material and a high melting point core material is used as the yarn of the base fabric or the fiber of the bat layer, and the low melting point sheath material is softened by the heat curing treatment of the felt. It is said that by forming a matrix in the bat fiber layer, it is possible to improve the dewatering performance of the felt and to enhance the compression resistance.

  A general felt configuration will be described with reference to FIG. The papermaking felt 10 is formed in an endless shape, and includes a base 20 made of woven fabric or the like, and a bat fiber layer 30 entangled and integrated with the base 20 by a needle punch. The base body 20 is configured to develop the mechanical strength of the felt 10. In FIG. 1, a woven fabric obtained by weaving the MD yarn 22 and the CD yarn 21 is used.

The environment for using this 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 of the press section has increased. That is, as a recent trend in papermaking technology, to improve productivity, the speed of paper machines and high pressurization with rolls or shoe presses in the press part have progressed, and the compression recovery of papermaking felt has become early under high pressure. Therefore, there is a problem that water permeability is deteriorated and water squeezing is significantly reduced.
In addition, with the increase in the speed of the paper machine, the vat fibers that make up the felt are violently worn away, and hair removal progresses, causing various troubles such as uneven paper quality and insufficient printability.
Therefore, as for the required performance of the felt, with regard to the basic water squeezing, smoothness, and hair removal resistance, a higher level of performance is required in the latest high-speed paper machine.

  Conventionally, various configurations have been proposed as means for solving this problem. For example, a proposal has been made to maintain the felt water permeability by increasing the ratio of the base portion. As a method for increasing the ratio of the base portion, as disclosed in Patent Document 2, a plurality of endless woven fabrics such as bag weaves, or endless woven fabrics obtained by joining both ends of the endless woven fabrics are made of a plurality of materials. There is a method of superimposing and laminating bat fibers and then entangled and integrated by needling.

Japanese Patent Application Laid-Open No. 08-302584 JP2003-13385A U.S. Pat.No. 5,651,394

However, the felts of Patent Documents 1 and 2 have a problem that they are easily subjected to repeated compression fatigue by a press device.
Moreover, when using 2 component material for a bat layer like the felt of patent document 1, after heat-treating felt, the low melting point material of 2 component material was softened, and it was made to infiltrate the cross section of a bat fiber or a base fabric, It hardens to form a matrix and the base fabric is strengthened to exhibit compression resistance, but is less compressed by pressurization, resulting in poor smoothness and water squeezability.

  An object of the present invention is to provide a papermaking felt that eliminates the above-mentioned drawbacks, has good water squeezing property, wet paper smoothness and durability, and has excellent hair removal resistance.

  As a result of examining the structure of the felt suitable for these purposes, the present invention uses at least two substrates (A and B) laminated, and at least one of the laminated substrates has a sweet-twisted structure containing core-sheath composite fibers. It consists of yarn, and the yarn is likely to be flat, and the gap between the yarns is configured to be 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, We have found that the above objective is achieved. Here, the gap between the yarns means a gap in a warp or weft yarn arrangement (gap between yarns) and a gap inside the yarn (gap between single yarns constituting a twisted yarn and single yarns).

  That is, the present invention relates to a papermaking felt formed by laminating two or more substrates of the same type or different types and a bat fiber containing a core-sheath composite fiber on one or both sides thereof, and entangled and integrated by needling. Among them, the felt for papermaking is characterized in that at least one substrate is a substrate composed of a twisted yarn composed of a sweet-twisted warp (MD yarn) or a weft (CD yarn) containing a core-sheath composite fiber.

  In the present invention, the base is composed of warps and wefts in the form of ends, and a laminated base is formed by laminating the base a plurality of times. The warp yarn (MD yarn) or the weft yarn (CD yarn) is flat and 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. It is a characteristic felt for papermaking.

  Further, in the present invention, the base is a multi-woven fabric woven with a double weave or more, the warp (MD yarn) or weft (CD yarn) containing the core-sheath composite fiber constituting the multi-woven fabric is flat, and The felt for papermaking is characterized in that the gap between the yarns 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.

  In the present invention, either the warp or the weft forming the base is a yarn containing a core-sheath composite fiber, and is a sweet-twisted twisted yarn twisted with a filament having a fineness of 50 to 400 dtex. For felt.

  Further, the substrate of the present invention is composed of a yarn having a specific fineness, thereby providing an effect of flattening the yarn. In order to further enhance this effect, the number of twists of the twisted yarn is 30 to 100 per 1 m. It is effective to use a sweet-twisted yarn having a spinning range and a ratio of 1.2 to 1.4 in the ratio of lower to upper. By making such 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.

  Here, when the number of the lower twist and / or the upper twist exceeds 100 times / m, the twisted yarn becomes a strong twisted yarn, and it is difficult to achieve the effect of the present invention to obtain a twisted yarn that becomes flat when a substrate is formed. . 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 formed, and a stable sweet twisted yarn having no knots and yarn variations is obtained. If the ratio of the number of lower twists / the number of upper twists is out of the range of 1.2 to 1.4, twisting of the twisted yarn will occur in the substrate when the substrate is constructed, and it will not be evenly flat.

  The sweet-twisted yarn (twisted yarn) of the present invention comprises a bundle of filaments containing core-sheath composite fibers, and the filament ratio of the core-sheath composite fibers may be in the range of 25% to 75% with respect to the total number of filaments of the twisted yarn. preferable. When the filament ratio 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 deteriorated. If the filament ratio of the core-sheath composite fiber exceeds 75%, the yarn becomes too flat, and the fixation with the bat fiber containing the core-sheath composite fiber is too strong, and the felt squeezing becomes worse. .

  The sweet-twisted yarn of the present invention may be a spun yarn made of staple fibers having a fineness of 6 to 50 dtex including core-sheath composite fibers.

  In the present invention, since the sweet-twisted yarn of the substrate is flat and the gap between the yarns is closed, it is possible to obtain a felt excellent in wet paper smoothness and hair removal resistance. In order to make the yarn of the substrate easy to be flat, when a substrate composed of warps and wefts in an end shape is used as the substrate, a laminated substrate is formed by laminating the substrate multiple times, and the upper layer Since the sweet twisted yarns are arranged so as to fill the gap between the lower twisted yarns, the layer of the laminated substrate becomes dense. The bat fiber including the core-sheath composite fiber is entangled and integrated with the laminated base by needling, and the laminated base is obtained by melting the low melting point component of the bat fiber of the core-sheath composite fiber and the low melting point component of the yarn by the action of heat. The yarn gap is easily closed.

  Further, in another embodiment for making the sweet-twisted yarn flat and easily closing the gap, the sweet-twisted yarn constituting the multiple-woven fabric is obtained by making the base into a multiple-woven fabric woven with a double weave or more. As in the case of the end laminated substrate, the gap between the sweet-twisted yarns of the multi-woven fabric is easily closed by melting the low melting point component of the bat fiber of the core-sheath composite fiber and the low melting point component of the yarn. Can be removed.

  In addition, in order to make it easier for the sweet-twisted yarn to form a flat yarn when it constitutes the substrate, and to easily close the gap between the sweet-twisted yarn, the smaller the number of entanglement points of the MD yarn and the CD yarn of the substrate, the smaller It is effective. For this purpose, it is possible to weave using either a solvent-soluble, particularly water-soluble filament, in either the MD yarn or the CD yarn. After the batt fiber is implanted in the woven fabric thus woven by the needle punch technique, the single yarn of the woven fabric is dissolved and removed, so that the gap between the yarns can be more easily blocked. .

  As a raw material for the solvent-soluble filament, polyvinyl alcohol, acrylic, polyester, or the like can be used, and water-soluble polyvinyl alcohol is particularly preferable.

  Except for the case where the solvent-soluble filament is used, nylon and polyester are used as the twisted yarn and single yarn constituting the substrate, but nylon yarn is particularly preferred because of excellent strength and durability.

  Further, in the present invention, the felt is obtained by needling a bat fiber containing a core-sheath composite fiber on one side or both sides of the substrate and entangled with the substrate. Since the low melting point component of the core-sheath composite fiber and the low melting point component of the yarn of the base material including the core-sheath composite fiber can be fixed by melting, the bonding force between the base material and the bat fiber layer is increased, and it is resistant as a felt. Excellent hair removal properties. In particular, in the present invention, it is preferable to use a bat fiber containing a core-sheath composite fiber in the bat layer on the surface side (wet paper placement side) of the substrate.

  The content of the core-sheath composite fiber in the surface-side batt layer of the substrate is preferably 25% to 75%. When the content of the core-sheath composite fiber is 25% or less, the bonding force between the substrate and the batt fiber layer is weak and the hair removal resistance is poor. Moreover, since the compression recovery property of a bat fiber layer will worsen when the content rate of a core-sheath conjugate fiber is 75% or more, it will be inferior to water squeezing as felt.

  Further, 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 from the surface of the substrate toward the wet paper side.

  Nylon that is preferably used for the core component of the core-sheath composite fiber of the present invention is preferably nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, or the like. Specifically, polymerization of ε-caprolactam (nylon 6), polycondensation of hexamethylenediamine and adipate (nylon 66), polycondensation of 1,4-diaminobutane and adipate (nylon 46), hexamethylenediamine and sebacine Nylon obtained by polycondensation of a nylon salt, such as polycondensation of an acid salt (nylon 610) or polycondensation of hexamethylenediamine / dodecanedioate (nylon 612), is preferable, and DSC (differential scanning calorimeter) Mention may be made of aliphatic nylons having a melting point of 200 ° C. or higher.

  The nylon used for the sheath component of the core-sheath composite fiber is a nylon having a lower melting point than that of the core component. As nylons preferably used for the sheath component, binary copolymer nylons such as nylon 6/12, nylon 6/610, nylon 66/6, nylon 66/12, nylon 66/610, nylon 6/66/12, nylon Mention may be made of terpolymer nylons such as 6/66/610. It is well known that the melting point of these copolymer nylons varies depending on the composition (% by weight of the copolymer component), but the copolymer nylon that can be used in the present invention has a melting point of 180 ° C. or less. Limited to.

  According to the present invention, at least one of the laminated substrates is made of a sweet-twisted yarn containing a core / sheath composite fiber, and becomes flat when the yarn constitutes the substrate, and a gap between the yarns includes a core / sheath composite fiber. Since the construction is such that the low melting point component of the fiber and the low melting point component of the yarn are melted, a papermaking felt excellent in water squeezing property, wet paper smoothness and hair removal resistance of the papermaking felt can be provided.

An example of the embodiment of the present invention will be described with reference to FIG. First, the papermaking felt 100 of the present invention includes a base body 200 and a bat fiber layer 300. The batt fiber layer 300 is formed by entanglement and integration of batt fibers (staple fibers) to the substrate 200 with a needle punch.
The substrate 200 includes two substrates, that is, a substrate A (210) and a substrate B (220). One of the substrates 210 is a material for imparting the mechanical strength of the felt 100 and 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 MD yarn 212 and CD yarn 211 can be used. In FIG. 2, dissimilar substrates 210 and 220 are laminated, but the same material may be used as long as the substrate (B) 220 satisfies the requirements of the present invention.

  The base 210 is made of MD yarn and CD yarn to form a woven fabric having a width narrower than the felt to be completed, and this woven fabric is wound in a spiral and the edges of adjacent woven fabrics are joined together. What was obtained can also be used. Further, it may be a substrate obtained by winding a substrate made of MD yarn and CD yarn having the same width as the felt to be completed on the same axis. In addition to a woven fabric, a substrate obtained by fixing MD yarns with an adhesive, or a substrate simply stacked without woven MD yarns or CD yarns may be used.

  In the present invention, in addition to the base A210, another base B220 is laminated to constitute the entire base 200. The substrate 220 is a woven fabric woven by a combination of warp (MD yarn) and weft (CD yarn), which is a feature of the present invention. That is, either the warp or the weft is a twisted yarn including a core-sheath composite fiber composed of a filament having a fineness in the range of 50 to 400 dtex, and the other is a filament or solvent-soluble in the range of 50 to 600 dtex. A woven fabric woven by filaments.

  In FIG. 2, bat fibers are entangled and integrated on both surfaces of the base body 200 by needle punching. In order to be 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, the core / sheath composite is formed on the surface 220 (wet paper placement side) of the base 220. It is preferable to form a batt fiber layer containing fibers.

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

Hereinafter, the present invention will be specifically described with reference to examples. In each example, another substrate B (220, 230, 240, 250) having the features of the present invention is laminated on the substrate A (210) to constitute the entire substrate 200. All of the following configurations were used.
Configuration of base 210:
(1) MD yarn and CD yarn
The MD yarns and CD yarns used the following twisted yarns in common.
(2) Twisting condition: `` 2/2/220 ''
(However, the display format of the twisted yarn in “” represents “the 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) Lower twist: S direction 250 times / m
(4) Upper twist: 160 times / m in the Z direction
Both the lower twist and the upper twist are 150 times / m or more, and belong to the strong twisted yarn.
(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 woven substrate (woven fabric) 210 was woven.

As shown in FIG. 2, a felt in which a batt fiber layer 300 was laminated on a substrate 200 obtained by laminating the following substrate 220 as a substrate B on a substrate A (210) was prepared.
Configuration of base 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: S direction 42 times / m
(d) Upper twist: Z direction 30 times / m
(e) Twist ratio (bottom / top): 1.40
(2) CD yarn: single yarn (diameter 330dtex)
(3) Weaving:
A base (woven fabric) 220 of 3/1 flat bag weave was woven with MD yarn: 40 / 5cm, CD yarn: 34 / 5cm.
(4) Formation of vat fiber layer:
A batt fiber layer 300 including a core-sheath composite fiber is formed on the upper surface of the substrate 220. The content of the core-sheath composite fiber is 25%.

In Example 1, a felt was prepared by laminating the following base 230 as the base B instead of the base 220. That is, in FIG. 2, a base body 230 is laminated instead of the base body 220.
Configuration of the base body 230:
(1) MD yarn: The following twisted yarn was used.
(a) Twisting condition: `` 2/2/220 ''
(b) Filament ratio of core-sheath composite fiber: Two filaments (50%) are included in the twisted yarn.
(c) Lower twist: S direction 42 times / m
(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 / 5cm, CD yarn: 34 / 5cm, 3/1 flat end-woven single woven fabric is woven, and the laminated substrate (woven fabric) 230 is formed by winding it twice. Configured.
(4) Formation of vat fiber layer:
Same as Example 1.

In Example 1, a felt was prepared by laminating the following base 240 as the base B instead of the base 220. That is, in FIG. 2, a base body 240 is laminated instead of the base body 220.
Configuration of base 240:
(1) MD yarn: The following twisted yarn was used.
(a) Twisting condition: `` 2/2/220 ''
(b) Filament ratio of core-sheath composite fiber: Two filaments (50%) are included in the twisted yarn.
(c) Bottom twist: 70 times / m in S direction
(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 / 5cm, CD yarn: 34 / 5cm, 3/1 flat end-woven single woven fabric is woven, and the laminated substrate (woven fabric) 240 is formed by winding it twice. Configured.
(4) Formation of vat fiber layer:
A batt fiber layer 300 including a core-sheath composite fiber is formed on the upper surface of the base fabric 240. The content of the core-sheath composite fiber is 50%.

In Example 1, a felt was prepared by laminating the following substrate 250 as the substrate B instead of the substrate 220. That is, in FIG. 2, a base body 250 is laminated instead of the base body 220.
Configuration of base body 250:
(1) MD yarn: The following twisted yarn was used.
(a) Twisting condition: `` 2/2/220 ''
(b) Filament ratio of core-sheath composite fiber: Three 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: Filament made of 400dtex polyvinyl alcohol resin (water-soluble).
(3) Weaving:
A base fabric (woven fabric) 250 of 3/1 1/3 bag weave was woven with MD yarn: 90 / 5cm, CD yarn: 30 / 5cm.
(4) Formation of vat fiber layer:
A batt fiber layer 300 including a core-sheath composite fiber is formed on the upper surface of the substrate 250. The content of the core-sheath composite fiber is 75%.
(5) Hot water scouring:
After forming the batt fiber layer 300, as hot water scouring, it was immersed in warm water at 40 ° C. for 30 minutes to dissolve the CD yarn, and a base body 250 consisting only of MD thread was formed on the base body 210.

[Comparative Example 1]
As shown in FIG. 3, a felt was prepared by forming a batt fiber layer similar to that of Example 1 as a substrate 260 formed by laminating the same substrate 210 on the substrate 210.

The felts prepared in Examples 1 to 4 and Comparative Example 1 were circulated between a pair of rolls at a cloth speed of 2 m / min, heat-treated while applying hot air of 180 ° C., and a hot press roll having a surface temperature of 160 ° C. Was made in contact with the felt surface-side butt layer to produce a papermaking felt. The same amount (basis weight; g / m ² ) of the vat fiber layer of all felts was prepared, and the paper smoothness index, compression recovery and durability, and hair removal resistance of these papermaking felts were determined by the following method. It was evaluated with.

(1) Paper smoothness index In accordance with 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. It shows that the higher the index, the smaller the unevenness of the uneven distance and the higher the smoothness.

(2) Compression recovery performance and sustained performance Felt is passed through the experimental device shown in Fig. 4, and the thickness of the felt is measured with a sensor at each initial stage when no pressure is applied, when compressed with a press roll, and after pressure release. The rate and the recovery rate were calculated by the following formulas, thereby evaluating the felt compression recovery performance and sustainability.
Compression rate (%) = (felt thickness during compression / felt thickness without initial pressure) x 100
Recovery rate (%) = (felt thickness immediately after pressure release / felt thickness during compression) x 100

  The experimental device consists of a pair of press rolls PR, PR, a plurality of guide rolls GR that support the felt with a certain tension, and a sensor (not shown) that measures the thickness of the felt when pressed by the press roll. And a second sensor (not shown) for measuring the thickness of the felt immediately after releasing the pressure. The driving conditions of the experimental apparatus were a press pressure of 100 kg / cm, a felt driving speed of 1000 m / min, and continued for 120 hours.

  From the values of the compression rate and the recovery rate obtained by the above measurement, the sustainability of the compression recovery of Examples and Comparative Examples was evaluated, and this was expressed as a relative score. Here, the numerical value of Example 1 was set to a score of 3, and based on this, the score was better if it was more than that, and if it was less than that, the score was better. The results are listed in the table.

(3) Hair removal resistance function An experiment on hair removal resistance was conducted by measuring the amount of fibers dropped from the felt using a Taber polishing tester based on JIS1023-1992. In this tester, a disk-shaped test piece is placed on a rotating turntable, and a rotating roll having a high resistance is brought into contact with the test piece to measure the amount of fiber dropout. In the experiment, the amount of fallen fibers (hair removal fibers) after rotating the turntable 5000 times was measured. The evaluation was expressed as a relative comparison when the amount of hair removal (amount of fallen fibers) in Comparative Example 1 was 100. The results are listed in the table.

  As is clear from the results in Table 1, according to the present invention, one of the laminated substrates is made of a sweet-twisted yarn containing a core-sheath composite fiber, the yarn (twisted yarn) is flat, and the gap is a melt of a low melting point component. Therefore, the paper smoothness, the compression recovery, and the sustainability were good. Moreover, the papermaking felt has a good hair removal resistance. In both the MD yarn and the CD yarn, the felt of the comparative example in which only the substrate 210 woven using the same twisted yarn was laminated had poor paper smoothness index and hair removal resistance.

  According to the present invention, a felt excellent in compression recovery and hair removal resistance can be obtained. When this is used as a felt for papermaking, it has excellent compression ratio and recovery rate due to pressurization with a roll or shoe press in the papermaking process, so that wet paper smoothness is not lost, and hair loss is suppressed, and water squeezing is good. Moreover, high water squeezability is maintained for a long time. In addition, high-performance felts that can cope with recent increases in the speed of paper machines and high pressure in the press section are provided.

Sectional drawing of the conventional general papermaking felt. Sectional drawing of the felt for papermaking of this invention Examples 1-4. Sectional drawing of the papermaking felt of the comparative example 1. FIG. Experimental apparatus of the present invention Schematic diagram of press machine

Explanation of symbols

10 Paper felt
20 substrate
30 Butt fiber layer
22 MD yarn
21 CD yarn
100 Papermaking felt
200 substrate
210 Base A
220 Base B
230 Base B
240 Base B
250 Base B
260 Base
300 butt fiber layer
PR press roll
GR guide roll

Claims (6)

In a papermaking felt formed by laminating two or more substrates of the same type or different types and a bat fiber including a core-sheath composite fiber on one or both sides thereof, and entangled and integrated by needling, at least one of the substrates A felt for papermaking, wherein the substrate is a substrate composed of a twisted yarn comprising a warp yarn (MD yarn) or a weft yarn (CD yarn) containing a core-sheath composite fiber. The base body is composed of warps and wefts in an end shape, constitutes a laminated base body formed by laminating the base body a plurality of times, and a sweet-twisted warp thread (MD yarn) including the core-sheath composite fiber of the laminated base body ) Or weft (CD yarn) is flat, and 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. The papermaking felt according to claim 1. The base is a multi-woven fabric woven with a double weave or more, and the warp (MD yarn) or weft (CD yarn) containing the core-sheath composite fiber constituting the multi-woven fabric is flat, and the gap between the yarns 2. The papermaking felt according to claim 1, wherein the felt is closed by melting of the low melting point component of the bat fiber containing the core-sheath composite fiber and the low melting point component of the yarn. The papermaking felt according to any one of claims 1 to 3, wherein the yarn containing the core-sheath composite fiber is a twisted yarn in which two or more filaments having a fineness of 50 to 400 dtex are twisted. The number of upper twists of the twisted yarn is in the range of 30 to 100 times per meter, and the ratio of the lower twist to the lower / upper is in the range of 1.2 to 1.4. The felt for papermaking as described in any one. 4. The papermaking felt according to claim 1, wherein either one of the warp (MD yarn) or the weft (CD yarn) constituting the substrate is a solvent-soluble filament.

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