KR20080100418A - Press felt for papermaking - Google Patents

Abstract

This invention provides a press felt (10) for papermaking, comprising a substrate (30), a wet paper-side vat layer (20) and a press-side vat layer (23). The wet paper-side vat layer (20) comprises a wet paper contact-side vat layer (21) and a substrate-side vat layer (22). The wet paper contact-side vat layer (21) comprises a core-sheath composite fiber (41) comprising a core component of a high-molecular weight nylon having an absolute viscosity of not less than 80 mPa.s and a sheath component of a nylon having a lower melting point than the core component. The substrate-side vat layer (22) comprises a layer of a nylon fiber (42) free from the core-sheath composite fiber (41). The sheath component of the core-sheath composite fiber (41) is melted to render the wet paper contact-side vat layer (21) dense, and, consequently, moisture in the press-side vat layer (23) is less likely to be moved to the wet paper side, whereby a remoistening phenomenon can be suppressed. Further, since the substrate-side vat layer (22) comprises a nylon layer free from the core-sheath composite fiber, the balance among smoothness, defiber resistance, abrasion resistance, compression fatigue resistance, and water drainage is good.

Description

PRESS FELT FOR PAPERMAKING}

TECHNICAL FIELD The present invention relates to a paper press press (hereinafter simply referred to as a "press felt") used in a papermaking machine.

Conventionally, a press apparatus is used in order to set out from a wetland in a papermaking process. In the press apparatus, the wetland in which the strata are formed is undertaken with the press felt interposed by a press nip. In general, the press apparatus is composed of a plurality of press nips.

5 is a schematic view of a press nip in a press apparatus.

This press nip consists of a pair of press rolls P 'and P' and a pair of press felts 11 'and 11' which sandwich the wetland W ', and the press roll P In the pressurization portion of ', P', pressure is applied to the press felts 11 'and 11' and the wetland W ', and water is squeezed out from the wetland W', and the press felts 11 'and 11 are pressed. ') Is absorbed.

However, since the pressure applied to the wetlands W 'and the press felts 11', 11 'is suddenly released from the center (nip) of the pressurizing portion, the press felts 11', 11 'in this part. ) Volume expands rapidly. As a result, negative pressure is generated in the press felts 11 'and 11', and since the wetland W 'is made of thin fibers, the capillary phenomenon increases and the press felt 11' , 11 '), the migration of moisture back to the wetland side, ie re-wetting.

As a felt for preventing this rehumidity phenomenon, the press felt disclosed by Unexamined-Japanese-Patent No. 2004-143627 (patent document 1) is mentioned, for example. This is a felt composed of a base layer, a wet side batt layer and a press side batt layer, in which a hydrophilic nonwoven fabric is disposed in the wet side batt layer. It is said that the rehydration phenomenon can be effectively suppressed because the hydrophilic action exerts the water transfer action to the hydrophilic nonwoven fabric and the support action of the transferred water.

In addition, the paper press felt has a function of restoring the felt compressed by pressurization without flattening under pressure in order to maintain the function of squeezing water from the wetlands (compression resistance). Fatigue and the softening of the felt also increase the wetland smoothness (flatness), hair loss / wear resistance, etc. are also important.

As a felt having such a function, for example, a press felt comprising a fiber having a poncho structure composed of a two-component material is disclosed in Japanese Patent Laid-Open No. 8-302584 (Patent Document 2).

In this press felt, a bicomponent material composed of a low melting sheath material and a high melting core material is used as the fiber of the bat layer. The heat hardening treatment of the press felt softens the low-melting raw material to form a matrix in the batt layer, thereby improving the dewatering performance of the press felt and increasing the compressive resistance. It can be said.

Moreover, in order to cope with the recent high speed papermaking machine, the press felt which used the woven fabric which was excellent in the imparting property and smoothness is used. The woven fabric is a warp yarn (felt CMD fragrance yarn) and a weft yarn (similarly MD fragrance yarn), which are woven together in monofilament monofilaments. See Japanese Patent Application Laid-Open No. 2000-170086 / Patent Document 3).

However, the press felt of patent documents 1 and 2 has a problem that it is easy to receive the repeated compression fatigue by a press apparatus.

In addition, when a two-component material is used for the batt layer as in the press felt of Patent Literature 2, a decrease in the mechanical strength and chemical deterioration of the core material occurs due to the influence of the hot press during the manufacture of the felt. During the use of the press felt, fibers were often cut or hair loss / abrasion progressed, requiring much replacement early.

In the press felt of Patent Literature 3, since the fixability of bat fiber and woven fabric due to needle punching is worse than that of the conventional felt using a twist yarn, the hair loss / wear resistance of the felt is remarkable. Bad is known.

Therefore, a press felt having a well-balanced function such as compression fatigue resistance, smoothness, hair loss / wear resistance, and impingement resistance while suppressing the re-wetting phenomenon is required.

In view of the above problems, an object of the present invention is to provide a papermaking press felt which is excellent in smoothness, abrasion resistance, compressive fatigue resistance and water impingement, while suppressing re-wetting.

The present invention provides a paper press belt comprising a gas layer and a bat layer having a wetland side layer and a press side layer, wherein the wetland side layer is formed of a wetland contact side batt layer and a gas side batt layer. The wetland contact side batt layer comprises a core component composed of a high molecular weight nylon having an absolute viscosity of 80 mPa · s or more and a sheath composite fiber composed of a supercomponent composed of nylon having a lower melting point than the core component, wherein the wetland contact side batt layer The said subject was solved by the papermaking press felt characterized by consisting of the layer of nylon which does not contain this sheath composite fiber.

If the absolute viscosity is 80 mPa · s or more, nylon is dissolved in 100 ml of 0.5 g / 95% sulfuric acid, and the absolute viscosity measured at a temperature of 25 ° C. can be measured with a vibratory viscometer.

It is preferable that the content rate of the said poncho composite fiber in the said wetland contact side batt layer is 25%-75%.

The wetland contacting side batt layer may have a multi-layered structure, and in the wetland contacting side batt layer, the content of the poncho composite fiber may be increased stepwise from the press side toward the wetland side.

The base (sometimes referred to as "base layer") is preferably a woven fabric in which warp yarns (fellow CMD direction yarns) and weft yarns (similarly MD direction yarns) are woven from monofilament single yarns.

According to the present invention, the sheath component of the sheath composite fiber melts, and the wetland contact side batt layer becomes dense. As a result, the moisture of the press-side layer becomes difficult to move to the wetland side because the wetland contact-side bat layer becomes a barrier and can suppress the rehumidity phenomenon.

In addition, the core component of the above-mentioned core sheath fiber has a high viscosity, that is, the use of high molecular weight nylon improves the hair loss / wear resistance and the compressive fatigue resistance of the felt, and as a result, the felt life is extended (life) and the felt exchange recovery Reduced, less hair attached to the wetland by hair loss / abrasion, the paper quality is improved, the smoothness of the wetland contact surface can be obtained.

In addition, the wetland contact side batt layer is composed of a sheath composite fiber, and the gaseous batt layer formed on the wetland side surface in a gas is composed of a nylon layer that does not contain the sheath composite fiber, thereby providing smoothness, hair loss / wear resistance, and abrasion resistance. Compression fatigue and impingement are well balanced.

In addition, since the water permeability of the woven fabric is improved by using a woven fabric woven from monofilament single yarn, the felt can be constituted with excellent impingement properties.

1 is a cross-sectional view of a press felt embodiment of the present invention.

2 is a cross-sectional view of another embodiment of the press felt of the present invention.

3 is a schematic diagram of an apparatus for confirming the effect of the press felt of the present invention.

4 is a schematic diagram of an apparatus for confirming the effect of the press felt of the present invention.

5 is a schematic explanatory view of a press apparatus of the papermaking machine.

EMBODIMENT OF THE INVENTION Hereinafter, the papermaking press felt of this invention is demonstrated in detail.

1 is a cross-sectional view of the press felt 10 according to the present invention in the CMD direction.

"Machine direction MD" is a longitudinal direction in which a paper machine moves a press felt, and "Machine transverse direction (CMD)" is a horizontal direction which transverses the direction in which a paper machine moves a press felt.

As shown in FIG. 1, the press felt 10 includes a base 30, a wet side batt layer 20, and a press side batt layer 23, and has a wet side batt layer 20. Is composed of a wetland contact side batt layer 21 and a gas side batt layer 22 disposed inside the wetland contact side batt layer 21.

The wetland contact side batt layer 21, the base side batt layer 22, and the press side batt layer 23 are composed of staple fibers, and the base side batt layer 22 and the press side batt layer 23 are formed. ) Is integrally coupled to the wetland side and the press side of the base 30 by needle punching, and the wetland contact side batt layer 21 is integrally coupled to the base side batt layer 22 by needle punching. have.

In the press felt 10 of the present invention, the wetted contact side batt layer 21 is composed of a core component composed of a high molecular weight nylon having an absolute viscosity of 80 mPa · s or more at a temperature of 25 ° C., and a nylon having a lower melting point than the core component. The staple fiber of the sheath composite fiber 41 which consists of a herbaceous component, and the base side batt layer 22 is comprised by the staple fiber of the conventional nylon fiber 42 which does not contain the sheath composite fiber 41 .

The absolute viscosity at the temperature of 25 ° C. is 80 mPa · s or more, and is the absolute viscosity measured at 25 ° C. by dissolving nylon in 100 g of 0.5 g / 95% sulfuric acid, which can be measured by a vibratory viscometer.

In Fig. 1, for convenience, the sheathed composite fiber 41 is exaggerated.

Conventionally, when using a fiber having a poncho structure composed of a two-component material for the batt layer of the press felt, the viscosity of the core component, that is, the molecular weight has not been considered. In the present invention, the core component uses a higher viscosity than conventionally, i.e., high molecular weight nylon, and the outer layer of the gas-side bat layer formed on the surface of the wetland side in the base of the layer (wetland contact-side bat layer) made of the sheath composite fiber. By arrange | positioning to it, the smoothness, alopecia / wear resistance, and compression fatigue resistance are well-balanced.

The nylon used for the core component of the sheath composite fiber 41 is a high molecular weight nylon with an absolute viscosity of 80 mPa · s or more at a temperature of 25 ° C., and a melting point higher than that of the initial component. By making nylon of core component into high viscosity (80 mPa * s or more), the hair loss resistance / wear resistance and compression fatigue resistance of a felt are improved. This is considered to be because the high molecular weight nylon has a longer molecular chain, thereby improving the mechanical properties (durability such as strength, friction, and abrasion) due to the entanglement effect between the molecular chains. When nylon with an absolute viscosity of less than 80 mPa · s (medium viscosity) is used, the effects of hair loss / wear resistance and compression fatigue resistance are not sufficiently obtained.

The nylon preferably used as the core component is preferably high molecular weight nylon 6, high molecular weight nylon 66, high molecular weight nylon 46, high molecular weight nylon 610, high molecular weight nylon 612 and the like. Specifically, polymerization of ε caprolactam (nylon 6), polycondensation of hexamethylenediamine / adipic acid (nylon 66), 1,4-diaminobutane / adipinate Polycondensation (nylon 46), polycondensation of hexamethylenediamine / sebacic acid (nylon610), polycondensation of hexamethylenediamine / dodecanedioic acid (nylon) 612) and the like, nylons obtained by polycondensation of nylon salts are preferable, and examples thereof include aliphatic nylons having a melting point of 200 ° C or higher by DSC (differential scanning thermal analysis system). The absolute viscosity at 100 g of 0.5 g / 95% sulfuric acid of these polymer nylons is preferably 80 mPa · s or more. In addition, these high molecular weight nylons are known by a known polymerization method or a method of solid-phase polymerization in which a nylon flake once polymerized is placed in an inert gas atmosphere at 120 to 200 ° C. containing no oxygen (e.g., For example, those manufactured by Japanese Patent Application Laid-Open No. 2002-529604) are used.

As the nylon used as the initial component of the core sheath composite fiber 41, nylon having a lower melting point than that of the core component is used. As a nylon which is preferably used as a super ingredient, binary copolymerized nylon, such as nylon 6/12, nylon 6/610, nylon 66/6, nylon 66/12, nylon 66/610, nylon 6/66/12, nylon 6 / Ternary copolymerized nylon, such as 66/610, is mentioned. It is well known that these copolymerized nylons have a melting point that varies depending on the composition (% by weight of the copolymerization component). However, the copolymerized nylon that can be used in the present invention is limited to those having a melting point of 180 ° C or lower.

When the supercomponent melts at the time of hot pressing in the manufacturing process of the press felt, fiber shrinkage of the core sheath composite fiber 41 occurs, whereby the wetland contact side batt layer 21 becomes dense, thereby improving the smoothness of the felt surface.

When the wetland contact side batt layer 21 becomes dense, when the press felt 10 goes out under nip pressurization, the base 30 and the base side batt layer 22 formed on the wetland side surface of the base, Moisture in the press-side bat layer 23 formed on the surface of the press-side becomes difficult to move due to the barrier of the dense layer, and the rewet phenomenon is effectively suppressed.

In the present invention, the gas-side bat layer 22 does not contain the sheath composite fiber 41 but is composed of ordinary nylon fibers 42, and only the wetland contact side bat layer 21 contains the sheath composite fiber 41. It was set as the structure which becomes. Accordingly, smoothness, hair loss / wear resistance, compression fatigue resistance and imparting resistance are well balanced. When the sheath composite fiber 41 is included in the gas-side bat layer 22, the sheath component melts and the entire batt layer formed on the wetland-side surface of the gas becomes incompressible. Will be impaired.

The wetland contact side batt layer 21 is preferably composed of fibers in which the sheath composite fiber 41 and the normal nylon fiber 42 are blended in a constant ratio, thereby providing smoothness / wear resistance and compressive fatigue resistance. It can be better balanced. In this case, the blending ratio is preferably 75% to 25% of the core sheath composite fiber 41 and 25% to 75% of the nylon fiber 42.

In the case where the content of the sheath composite fiber 41 is less than 25%, the denseness of the wetland contact side batt layer 21 is lowered, so that the smoothness of the felt surface is deteriorated and the effect of suppressing the re-wetting phenomenon is not sufficiently obtained.

On the other hand, when the content rate of the poncho composite fiber 41 exceeds 75%, it is excellent in the smoothness and abrasion resistance of the felt, and can effectively suppress the re-wetting phenomenon, while the wetland contact side batt layer 21 is easy to be fatigued easily. It tends to be easy to peace.

In addition, the wetland contact side batt layer 21 may have a multi-layer structure, and in the wetland contact side batt layer 21, the content of the sheath composite fiber 41 may be increased stepwise from the press side toward the wetland side. And wear resistance can be further improved.

FIG. 2 shows an embodiment in which the wetland contact side bat layer 21 has a two-layer structure of the first layer 21a and the second layer 21b, and the first layer 21a is formed by the first layer 21a. The content of the sheath composite fiber 41 is larger than the two layers 21b.

By such a structure, the wetland contact side batt layer 21 can have a good balance of rewetability and impingement. That is, since the 1st layer 21a which has a lot content of the poncho composite fiber 41 becomes dense, rehydratability and smoothness can be maintained, and the 2nd layer 21b which has less content of the poncho composite fiber 41 is Since the compactness is low but the compressibility is contributed, the impingement property is improved, and as the wetland contact side batt layer 21, re-wetting and impingement property can be given simultaneously. From this, the wetland contact side bat layer 21 maintains smoothness and hair loss / abrasion compared with the case of a single layer, and since the dense layer is composed of two layers, the rehumidity is further improved and the impingement property is also improved. It will be provided.

On the contrary, when the content of the sheath composite fiber 41 is reduced stepwise from the press side to the wetland side in the wetland contacting side batt layer 21, the structure is inverse to that described above. Compared to the case where the bat layer 21 is a single layer, smoothness, hair loss / wear resistance, and rehumidity are deteriorated.

In FIG. 2, the wetland contact side batt layer 21 is made of two layers, but may be composed of three or more layers.

Although the volume ratio of the core part and the core part of the poncho composite fiber 41 is not specifically limited, It is the range of 5: 1-1: 5, Preferably it is 1: 1.

In addition, the nylon fibers 42 constituting the wetland contact side batt layer 21 and the press side batt layer 23 and the sheath composite fiber 41 are nylon 6, nylon 66, and nylon 46. , Nylon 610, nylon 612 and the like are suitable.

The base 30 is preferably a woven fabric obtained by weaving warp yarns 31 (felt CMD direction yarns) and weft yarns 32 (similarly MD direction yarns) with monofilament single yarns, as shown in Figs. Although it is used, it can be used as a double tissue such as (2/1, 1/2), (3/1, 1/3), (5/1, 1/5), triple tissue, or ( Single tissue + double tissue), (double tissue + double tissue) and the like can be used. The monofilament single yarn has a diameter of 0.1 mm to 0.6 mm and a yarn density of 10 to 100 pieces / 25 mm can be used.

In addition, the present invention is not limited to this, and a wide band is obtained by winding a structure, film, knitted fabric, and thin band in spiral without forming the MD direction and the CMD direction real. Various structures, such as a structure, can be employ | adopted suitably. As the material of the base 30, synthetic fibers such as natural fibers such as wool, polyesters having excellent abrasion resistance, fatigue resistance, elongation characteristics, antifouling properties, and nylon 6, nylon 66, etc. Fiber is used.

Fineness of the poncho composite fiber 41 is about 15-25 decitex in pick-up felt used at the front end of the press part of the paper machine. In the felt for the 2nd press or the 3rd press used in the middle part of the press part of the press, about 10-20 decitex may be used.

Moreover, in the 4th press used for the back end of the paper machine press part, or the felt for shoe press, about 5-20 decitex should be used.

The fineness of the nylon fiber 42 is about 10-25 decitex in the wet side batt layer 20 of the picking felt used in the front end of the press part of the paper machine, and 15 in the press side batt layer 23. It is good to use about -25 decitex.

Also, about 10 to 15 decitex in wetland side batt layer 20 of the felt for press 2 or 3 used in stopping the press part of the paper machine, and 10 to 20 in the press side batt layer 23. Use fineness of about decitex.

Also, about 5 to 15 decitex in the wet side batt layer 20 of the felt for press 4 or shoe press used at the rear end of the press part of the paper machine, and 5 to 20 dec in the press side batt layer 23. Use fineness of about dtex.

(Example)

The papermaking press felt of this invention is demonstrated concretely by the following example.

However, the present invention is not limited to these examples.

Preparation of myocardial composite fibers;

Refined nylon 6 (caprolactam: melting point: 220 ° C) and copolymerized nylon 6/12 (caprolactam / laurolactam: melting point: 140 ° C) were prepared, and each was devolatilized. After the individual injection into the extruder with the vent to eject volatiles, the volatiles are removed from the extruder, and the melted core nylon 6 and the copolymerized nylon 6/12 are melted in a fixed-quantity gear pump. It quantified by and supplied to each poncho composite spinning nozzle. The vinegar composite fiber spun through the vinegar composite spinning nozzle is oiled while cooling in a spinning chimney, and once wound into a natural draw ratio, and then stretched and crimped. (Iv) After processing, it was cut to a predetermined length to prepare staple fibers of a core sheath fiber.

In addition, the manufacturing method of "MODEL-EMF made from Dongyang Precision Industries Co., Ltd." can be used for manufacture of a sheath composite fiber. In this apparatus, an extruder, a Nelson multistage drawing machine and a winding machine can be used.

In this embodiment, two kinds of core materials are high molecular weight nylon 6 (absolute viscosity at 25 ° C., 85 mPa · s, melting point 220 ° C.) and medium molecular weight nylon 6 (absolute viscosity at 25 ° C., 70 mPa · s, melting point 220 ° C.). Two types of staple fibers of a core sheath composite fiber having a volume ratio of core part and sheath part of 1: 1 were used, using copolymerized nylon 6/12 (melting point 140 degreeC) as a base material. Composite fiber A and high molecular weight nylon 6 are used as core material, and composite fiber B is used.

In the present embodiment, the numerical values of the absolute viscosity of 85 mPa · s and the absolute viscosity of 70 mPa · s are expressed by the relative viscosity (ηr etaal) by the general measuring means (Ubbelohde viscosity method), where ηr = 4.5 and 3.0. Becomes Therefore, the absolute viscosity of 80 mPa · s corresponds to ηr = 4.0.

Preparation of paper press felts;

In order that both the Example and the comparative example may make various conditions common, the basic structure of all the felt was as follows.

Gas: Woven fabric A ([2/1] made of twisted nylon monofilament of 240 dtex and plied yarns braided together, which are woven in MD and CMD directions (3/1) , 1/3) double tissue]: Basis weight 300g / m ²

: Woven fabric B (double structure of (3/1, 1/3) woven with nylon monofilament single yarn of 1100dtex as MD direction material and CMD direction material): Basis weight 300g / m ²

Bat layer: The wetland contact side bat layer (first layer) (referred to as "wetland contact fiber layer" in Table 1) has (gd6 of 17 dtex nylon 6 fiber and 17 dtex composite fiber A or B staple fiber) / m ²

: The wetland contact side batt layer (the second layer) has a gross basis weight of 120 g / m ^{2 (} a staple fiber of nylon 6 fiber of 17 dtex and composite fiber A of 17 dtex).

: Gas side batt layer (17dtex nylon 6 fiber and 17dtex composite fiber A staple fiber) with total basis weight of 120g / m ²

: Press side bat layer (17dtex nylon 6 fiber staple fiber) total basis weight 100g / m ²

Needling frequency density: 700 times / cm ²

Heat press: The felt after the needling frequency is passed through a pair of thermal calender rolls (roll temperature 160 ° C., press pressure 30 kg / cm) five times at a speed of 5 m / min. To give a felt having a density of at least 0.5 g / cm ³ .

The structures of the felts of Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Tables 1 and 2.

Table 1

 Example  One  2  3  4  5  6  7  8  Wetland contact fiber layer (first layer)  Compound A 60%  Compound A 40%  Compound A 10%  Compound A 60%  Compound A 40%  Compound A 70%  Compound A 70%  Compound A 60%  Wetland contact fiber layer (2nd layer)  nylon  nylon  nylon  Compound A 40%  Compound A 10%  nylon  Compound A 40%  nylon  First bat layer  nylon  nylon  nylon  nylon  nylon  nylon  nylon  nylon  understratum  Base A  Base A  Base A  Base A  Base A  Base A  Base A  Base B  Second batt layer  nylon  nylon  nylon  nylon  nylon  nylon  nylon  nylon

Table 2

 Comparative example  One  2  3  4  5  6  Wetland contact fiber layer (first layer)  nylon  nylon  Compound A 5%  Compound A 10%  Compound B 40%  nylon  Wetland contact fiber layer (2nd layer)  nylon  nylon  Compound A 5%  Compound A 40%  nylon  nylon  First bat layer  Compound A 60%  nylon  nylon  nylon  nylon  nylon  understratum  Base A  Base A  Base A  Base A  Base A  Base B  Second batt layer  nylon  nylon  nylon  nylon  nylon  nylon

Using the papermaking press felts of Examples and Comparative Examples, the following conditions and methods were used to evaluate rewetting phenomena and impingement resistance, and to evaluate fatigue fatigue resistance, alopecia / wear resistance, and smoothness.

Assessment of rehabilitation and impetus;

The rehumidity phenomenon and impingement were evaluated by the apparatus shown in FIG. 3 and FIG.

First, in the apparatus shown in Figs. 3 and 4, P is a press roll, 110 is a top felt, 10 is a bottom felt, SC is a suction tube, and SN is It is a shower nozzle.

In addition, the said Example and the comparative example are used as the bottom side felt 10 also in any apparatus. In this case, a press felt as shown in Comparative Example 2 was used as the top felt.

3 and 4, the driving speed of the felt is 800 m / min, and the press pressure is 80 kg / cm.

The apparatus shown in FIG. 3 has a structure in which the wetland which escaped under nip pressure is placed on the bottom side felt 10 and conveyed. Therefore, after deviating under the nip pressure, when the wetness degree of the wetland at the position (press exit 1) which is placed and conveyed on the bottom side felt 10 is measured, it is possible to obtain the water content data of the wetland where the rewet phenomenon occurred. .

On the other hand, in the apparatus shown in Fig. 4, the area where the bottom side felt 10 contacts the press roll is large, and the time when the wetland released under the nip pressure contacts the felts 10 and 110 is very short. Here, by measuring the wetness of the wetland at the position (press outlet 2) immediately after deviating under this nip pressure, the water content data of the wetland in which the remaining rewet phenomenon does not occur is obtained.

Here, the moisture content data by the apparatus of FIG. 3 and the same data by the apparatus of FIG. 4 were obtained, and rehydration phenomenon and impingementability were evaluated. In regard to the impingement evaluation, in the water content data at the press outlet 1 by the apparatus of Fig. 3, the water content of 48% or more and less than 49% was set to (impact performance "good"). And the thing more than 49% of moisture was made into (water impairment evaluation "defect"). Regarding the evaluation of the rehumidity phenomenon, the difference between the water content data by the apparatus of FIG. 3 and the same data by the apparatus of FIG. 4 does not occur when the difference is less than 0.5%. (Evaluation "good"). On the other hand, the difference between the two is 0.5% or more and less than 1.0%, and some rehumidity is occurring (evaluation "a"), and more than 1.0% is said to be rehumidification (evaluation "bad").

Repeated compression fatigue test;

The load was repeated 300,000 times with a 5 Hz pulse load at 120 kg / cm ² and the compression fatigue test was performed. Compression fatigue was shown by the ratio (density / initial density after test), and less than 1.30 was "good" 1.30 or more and 1.39 or less "good", and 1.40 or more were called "bad".

Taper hair loss / wear test;

Hair loss / wear resistance was evaluated by measuring the amount of fibers separated from the papermaking felt by a taper polishing tester in accordance with JIS1023-1992. A disk-shaped test piece was placed on a rotating turntable, and a roll of high resistance was brought into contact with the test piece to measure the amount of fibers dropped (hair loss / abrasion) (load: 0.5 kg, wheel). : CS-17, Speed: 3000 times, Unit: mg)

The amount of hair loss / abrasion which was 40 mg or less was "good" and the thing exceeding 40 mg was called "defect".

Measurement of surface roughness;

Ten average roughness Rz (μm) (JIS-B0601) of the initial felt before the taper hair loss / wear test was measured, and the smoothness of the felt surface was evaluated.

Surface quality less than 60 micrometers "excellent", 60 micrometers or more and 99 micrometers or less were "good", and 100 micrometers or more were "bad".

Table 3 shows the measurement results and evaluation of each test.

Table 3

Initial density (g / cm ³ )  Repeated compression fatigue test   Taper Wear Test (mg)   Surface roughness test (μm)  Impetus and Resorption Test % Moisture at press outlet (1) % Moisture at press outlet (2)  Impartiality Assessment  Rewet evaluation Example 1 0.470 1.36 (good) 20 (good) 50 (excellent) 48.6 48.3 Good Good Example 2 0.465 1.33 (good) 35 (good) 70 (good) 48.6 48 Good end Example 3 0.455 1.29 (Excellent) 45 (bad) 100 (bad) 48.9 47.5 Good Bad Example 4 0.475 1.39 (good) 25 (good) 50 (excellent) 48.5 48.5 Good Good Example 5 0.475 1.36 (good) 30 (good) 65 (good) 48.4 48 Good Good Example 6 0.475 1.39 (good) 25 (good) 45 (excellent) 48.6 48.4 Good Good Example 7 0.485 1.39 (good) 20 (good) 40 (excellent) 48.5 48.5 Good Good Example 8 0.485 1.38 (good) 30 (good) 50 (excellent) 48.1 47.8 Good Good Comparative Example 1 0.465 1.38 (good) 60 (bad) 120 (bad) 49 48.3 Bad end Comparative Example 2 0.450 1.20 (excellent) 60 (bad) 125 (bad) 49 47.3 Bad Bad Comparative Example 3 0.455 1.26 (Excellent) 55 (bad) 100 (bad) 49 47.6 Bad Bad Comparative Example 4 0.470 1.38 (good) 45 (bad) 100 (bad) 48.8 48.2 Good end Comparative Example 5 0.465 1.43 (bad) 65 (bad) 80 (good) 49 48.3 Bad end Comparative Example 6 0.455 1.20 (excellent) 60 (bad) 125 (bad) 48.4 47 Good Bad

As shown in Examples 1 to 8 of Table 3, the papermaking press felt of the present invention has a well balanced function of compressive fatigue resistance, hair loss / wear resistance, smoothness and impetusability while suppressing re-wetting phenomenon. It was confirmed. It can be seen that in Comparative Example 1 in which the gas-side bat layer was composed of the sheath fiber, the compression fatigue resistance and the hair loss / wear resistance were good, but the smoothness of the felt surface was inferior.

In addition, in Example 3, Comparative Example 3, and Comparative Example 2, which contained no vinegar fibers in the wetland contact-side bat layer, the content of the vinegar composite fiber was less than 25%, the compression fatigue resistance function was achieved, but the re-wetting phenomenon was not suppressed. I can see that it does not.

In addition, Comparative Example 4 in which the content of the sheath composite fiber was gradually reduced from the press side toward the wetland side in the wetland contact side batt layer achieved the function of compression fatigue resistance / humidity resistance, but the smoothness was poor. This is considered to be because the first layer of the wetland contact side batt layer containing less of the sheath composite fiber constitutes the felt surface.

In addition, it can be seen that the comparative example 5 using the medium molecular weight nylon as the core component of the core sheath composite fiber worsens the compression fatigue resistance and the hair loss / wear resistance compared with Example 1 using the high molecular weight nylon.

In addition, since Example 8 uses a woven fabric woven from monofilament single yarn as the base B for the base layer, the moisture (1 and 2) at the press outlet was lower than Example 1 using a woven fabric woven from monofilament yarns in the base A. Neither of these was low and it was confirmed that it was excellent in impingement property.

According to the present invention, the wetland contact side batt layer serves as a barrier to suppress re-humidity, and to make the core component of the vinegar composite fiber at a high viscosity, that is, by using high molecular weight nylon, hair loss / wear resistance and compression resistance of the felt. Fatigue is improved, and as a result, the life of the felt (life) is extended to reduce the number of felt exchanges, and less hair is attached to the wetlands due to hair loss / wear, thereby improving the papermaking quality and maintaining the smoothness of the wetland contact surface. Effect such as

In addition, the wetland contact side batt layer is composed of the sheath composite fiber, and the gaseous batt layer formed on the wetland side surface of the gas is composed of a nylon layer that does not contain the sheath composite fiber, thereby providing smoothness, hair loss / wear resistance, and compression resistance. The fatigue and imparting property are well-balanced, and by using a woven fabric woven from monofilament single yarn in the base layer, the water permeability of the woven fabric is improved to provide a felt having excellent impingement properties.

Claims (4)

In a press paper for felt composed of a batt layer having a base, a wetland side layer and a press side layer, The wetland side layer is composed of a wetland contact side bat layer and a gas side bat layer, The wetland contact side batt layer comprises a core component made of high molecular weight nylon having an absolute viscosity of 80 mPa · s or more, and a super component made of nylon having a lower melting point than the core component ( contains a core-sheath composite fiber composed of sheath, The gas-side bat layer is formed of a layer of nylon that does not contain the sheath composite fiber Paper press felt characterized by the above-mentioned. The method of claim 1, The content rate of the said poncho composite fiber in the said wetland contact side batt layer is 25%-75%, The papermaking press felt characterized by the above-mentioned. The method according to claim 1 or 2, The wetland contact side batt layer has a multi-layered structure, and in the wetland contact side batt layer, the content of the poncho composite fiber is gradually increased from the press side toward the wetland side. . The method according to any one of claims 1 to 3, The base paper press felt for papermaking characterized in that the said fabric is a woven fabric which consists of a warp and a weft of a monofilament single yarn.

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