JP2739517B2 - Felt for papermaking - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a felt for papermaking, and more particularly to a felt for use as a press felt in a wet part of a paper machine or a dry felt in a drying part in a dry part. The present invention relates to a papermaking felt used as a material for papermaking.

[Prior Art and Problems to be Solved by the Invention] A conventionally used papermaking felt is one in which a web made of nylon 6, nylon 66, or the like is entangled and integrated by needling on a base cloth. However, although the nylon material has toughness, it gradually loses elasticity due to repeated compression fatigue received on a paper machine, and eventually becomes flattened, losing the water squeezing performance as a papermaking felt, which is not appropriate. Therefore, as means for reinforcing this, Japanese Patent Application Laid-Open Nos. 53-28707, 57-171790,
Felts have been subjected to resin processing as disclosed in JP-A-3-159592 and JP-A-56-112593. However, a disadvantage of this resin-processed felt is that the resin bonded to the fiber surface or the fiber entanglement point has poor water resistance. Therefore, during wet use, the resin bonded to the fiber surface or the fiber entangled point gradually peels off.

In addition, the polymer used in the resin-processed felt has poor elastic persistence against repeated compression received on a paper machine, so that at the end of use of the felt, all of the web fibers and the resin are crushed and flattened, thereby losing water squeezing performance. Become.

The present invention has been made in view of the above points, and has as its object a good elastic persistence against repeated compression fatigue received on a paper machine, easy to be inserted into the paper machine, and flexible. It is an object of the present invention to provide a papermaking felt having improved properties, improved entanglement between web fibers, less hair removal, high surface smoothness, and good paper formation.

[Means for Solving the Problems] A papermaking felt according to the present invention is a papermaking felt obtained by intertwining and integrating a base fabric and a web, wherein the web contains polyelastomer fibers, and the surface of the web contains a polyelastomer. Is obtained by heat-sealing the nonwoven fabric of the above.

Further, in a papermaking felt in which a base fabric and a web are entangled and integrated, one nonwoven fabric of high-density polyelastomer is interposed in the web, or a plurality of webs and the nonwoven fabric are alternately laminated. In addition, a nonwoven fabric of a polyelastomer is thermally fused to the surface of the web.

Further, in a papermaking felt in which a base fabric and a web are entangled and integrated, the web contains polyelastomer fibers and one nonwoven fabric of high-density polyelastomer is interposed in the web, or a plurality of the webs are used. A web and the nonwoven fabric are alternately laminated, and a polyelastomeric nonwoven fabric is thermally fused to the web surface.

Further, as the non-woven fabric of the polyelastomer fiber and polyelastomer used in the papermaking felt according to the present invention, a urethane-based, polyamide-based, ester-based, styrene-based or olefin-based non-woven fabric is used, or two or more of these are used. Use in combination.

Further, the blended fiber constituting the web and / or the nonwoven fabric interposed in the web and the nonwoven fabric formed on the web surface are conjugate fibers of core / sheath type or side-by-side type, and any one of the constituent components of the conjugate fiber One or both are formed of a polyelastomer.

In the papermaking felt according to the present invention, the use of a polyelastomer as a raw material is based on the fact that the excellent rubber elasticity of the polyelastomer, the flexibility and the durability thereof are utilized, and the low melting point is utilized. is there. That is, since the melting point (220 ° C. or higher) of the felt base fabric or the conventional web fiber (nylon 6, nylon 66, etc.) is lower, the heat treatment can be easily performed.

Further, a non-woven fabric of a polyelastomer (for example, a non-woven fabric obtained by a melt blow method, a spun bond method, or the like) is formed on a web surface, and the non-woven fabric is heat-treated by heat pressing, kiss-touching with a heat roll, ultrasonic welding, or the like. Smoothness, fluffiness and mechanical hair loss are prevented.

Further, a felt in which a web is formed by blending a polyelastomer fiber and a conventional fiber (nylon 6, nylon 66, etc.), a nonwoven fabric of a high-density polyelastomer is interposed in the web, or a plurality of the webs are used. The felt in which the nonwoven fabric of polyelastomer is thermally fused to the web surface of each of the felts in which the nonwoven fabric and the nonwoven fabric are alternately laminated is improved in elastic durability due to the rubber elasticity of the polyelastomer. It is possible to achieve the effect of preventing hair loss, abrasion and fuzzing by the heat sealing effect of the polyelastomeric nonwoven fabric on the web surface, and to improve smoothness, and the polyelastomer itself has a high density High durability due to high density due to good entanglement between the web and the non-woven fabric of polyelastomer in the web Based on the fact that to improve. Therefore, it is suitable as a papermaking felt in a part where a high nip pressure is applied, such as a final press of a paper machine.

In addition, if the nonwoven fabric of the polyelastomer to be laminated is embossed first, the confounding property by needling can be further improved.

In addition, the felt which comprised the web only from the polyelastomer fiber cannot be tightened to the target density even if it is entangled by needling, and it becomes a bulky felt. For this reason, the felt retains a large amount of water and has poor water squeezing properties. Further, since the felt having no tightness is less entangled with the fibers constituting the web, the single fibers fall off due to the friction received on the paper machine and the hair loss becomes remarkable, which is not appropriate.

By the way, the performance of a polyelastomer varies depending on the combination of the ratio of hard segment / soft segment, which is the basic unit, the type, and the like, so that it cannot be determined unconditionally. However, there are generally the following rules of thumb. .

Elasticity persistence: Polyurethane, Polyamide>Polyester> Polystyrene, Polyolefin Mechanical resistance: Polyamide>Polyurethane>Polystyrene> Polyolefin Thermal adhesion: Polyolefin>Polystyrene> Polyurethane, Polyamide Hard segment As the ratio of the soft segment increases, the mechanical resistance, heat resistance, and chemical resistance improve.
Flexibility, elasticity persistence and impact resistance decrease.

The smaller the ratio of the hard segment / soft segment is, the opposite effect is obtained.

For example, the polyelastomer is a polyurethane elastomer, the hard segment is a polyurethane, the soft segment is a block copolymer of polyester or polyether and has a softening point in the range of 100 to 200 ° C., and the polyelastomer is an ester elastomer. A block copolymer consisting of polyester with a hard segment of polyether and a soft segment having a softening point in the range of 100 to 200 ° C. A polyelastomer is a styrene elastomer, a hard segment is polystyrene, and a soft segment is polybutadiene or polybutadiene. A block copolymer composed of isoprene having a softening point in the range of 80 to 200 ° C, a polyelastomer being a polyolefin-based elastomer, and a hard segment being polyethylene or polypropylene,
It is preferable that the soft segment has a softening point in the range of 100 to 160 ° C., which is a copolymer made of polyethylene rubber or polypropylene rubber.

Further, a part of the blended fiber constituting the web and / or the nonwoven fabric interposed in the web and the nonwoven fabric formed on the web surface are conjugate fibers of a core / sheath type or a side-by-side type, and the constituent components of the conjugate fiber When forming one or both of the polyelastomer,
Since the adhesion between polymer interfaces is related to the compatibility of the polyelastomers in the composite, usually, the polyelastomer / homologous polymer or the nylon / polyurethane, polyester / polystyrene, or polystyrene is used. / Polyolefin-based, polyester-based / polyolefin-based combinations.

[Example] Example 1 On the front side of a base fabric 1 composed of a warp monofilament twisted yarn and a weft monofilament twisted yarn generally used for a papermaking felt, a 1: 1 short fiber of a polyurethane-based polyelastomer and a short fiber of nylon 6 were applied. Eight 120 g / m ² blended web blended layers 2a are laminated, ^two web blended layers 2a are laminated on the back side of the base fabric 1, and the laminated front and back web blended layers 2a are entangled by needling. The web 2 was formed by bonding, and the surface of the web-blended layer 2a on the front side was covered with a 25 g / m ² polyurethane-based non-woven fabric 3a (melt blow method) of a polyurethane elastomer and entangled by needling. After the entanglement was completed, the surface was pressed with a hot roll while being stretched by a dryer, and heat-set with hot air to obtain a papermaking felt (see FIG. 1).

Example 2 A papermaking felt having the same method and structure as in Example 1 was obtained in the same manner as in Example 1, except that a polyamide-based polyelastomer was used as a raw material instead of the polyurethane-based polyelastomer.

Example 3 A papermaking felt having the same method and structure as in Example 1 was obtained, except that a polyester-based polyelastomer was used in place of the polyurethane-based polyelastomer in Example 1.

Example 4 A papermaking felt having the same method and structure as in Example 1 was obtained, except that a polystyrene-based polyelastomer was used in place of the polyurethane-based elastomer in Example 1.

Example 5 A papermaking felt having the same method and structure as in Example 1 was obtained, except that in place of the polyurethane-based elastomer, a polyolefin-based elastomer was used as the material.

Example 6 On the front side of a base fabric 1 comprising a warp monofilament twisted yarn and a weft monofilament twisted yarn generally used for papermaking felt, a polyurethane-based polyelastomer was used.
A 120 g / m ² nonwoven fabric 3 (melt blow method) is placed thereon, and a 120 g / m ² nylon single layer ² b made of nylon 6 short fibers is laminated thereon. Entangled with a ring. Further, after the needling, a 120 g / m ² nonwoven fabric 3 made of a polyurethane-based polyelastomer and a nylon single layer 2b are sequentially laminated to form a set and entangled again by needling. Thereafter, in the same manner, on the front side of the base cloth 1, a nonwoven fabric 3 of 120 g / m ^{2 made} of a polyurethane-based polyelastomer and a single layer of nylon 2b
Are alternately stacked and needling to form a total of eight layers.
Therefore, the uppermost layer of the eight layers is the nylon single layer 2b. Next, ^two nylon single layers 2b of 120 g / m ² consisting of short fibers of nylon 6 were laminated from the back surface of the base fabric 1 and entangled by needling. Next, a 25 g / m ² nonwoven fabric 3a (melt blow method) made of a polyurethane-based polyelastomer was laminated on the surface of the web 2 located on the front side of the base fabric 1 and entangled by needling. Finally, the needling of the whole was performed to achieve the entanglement and integration of the whole felt.
The felt with the entanglement completed was pressurized from the surface with a hot roll while being stretched by a dryer, and heat-set with hot air to obtain a felt for papermaking (see FIG. 2).

Example 7 A papermaking felt having the same method and structure as in Example 6 was obtained, except that a polyamide-based polyelastomer was used in place of the polyurethane-based polyelastomer in Example 6.

Example 8 A papermaking felt having the same method and structure as in Example 6 was obtained, except that a polyester-based polyelastomer was used in place of the polyurethane-based polyelastomer in Example 6.

Example 9 A papermaking felt having the same method and structure as in Example 6 was obtained, except that a polystyrene-based polyelastomer was used in place of the polyurethane-based elastomer in Example 6.

Example 10 A papermaking felt having the same method and structure as in Example 6 was obtained, except that a polyolefin-based polyelastomer was used in place of the polyurethane-based elastomer in Example 6.

Comparative Example 1 On the front side of a base fabric composed of warp monofilament twisted yarns and weft monofilament twisted yarns generally used in papermaking felts, eight layers of only 120 g / m ² nylon single fibers made of nylon 6 short fibers were laminated. to the back side of the base fabric nylon single layer of 120 g / m ² consisting of staple fibers of nylon 6 only 2
The layers were laminated and entangled by needling to form a web to obtain a papermaking felt.

Comparative Example 2 Eight layers of a 120 g / m ² polyelastomer single layer composed of polyamide-based polyelastomer short fibers were laminated on the front side of a base fabric composed of a warp monofilament twisted yarn and a weft monofilament twisted yarn generally used for a papermaking felt. On the back side of the base fabric, only a single layer of a 120 g / m ² polyelastomer composed of short fibers of polyamide-based polyelastomer was laminated and entangled by needling to form a web to obtain a papermaking felt. Was.

Table 1 shows the compression fatigue test, Taber abrasion test, and unevenness of prescale color when pressed under a constant load for the felts for papermaking obtained in Examples 1 to 10 and Comparative Examples 1 and 2, and the smoothness of the felt surface. Are shown.

As can be seen from Table 1, each of the papermaking felts of Examples 1 to 5 has a lower density increase rate after compression fatigue, less flattening due to pressurization, and a good persistence of elasticity as compared with Comparative Example 1. Met. In addition, the amount of wear and the surface smoothness were improved as the effects of hot pressing.

Furthermore, each of the papermaking felts of Examples 6 to 10 has almost the same improved elastic durability, abrasion resistance (hair removal) and surface smoothness as those of Examples 1 to 5 described above.

In addition, the papermaking felt of Comparative Example 2 is disadvantageous in terms of the abrasion loss and smoothness because the finished density cannot be increased.

Example 11 In the same manner as in Example 6, a 120 g / m ² nonwoven fabric (melt blow method) made of a polyurethane-based polyelastomer was placed on the front side of the base fabric, and short fibers of the polyurethane-based polyelastomer and nylon 66 were placed thereon. A 120 g / m ² web blended layer in which short fibers are blended at a ratio of 1: 1 is laminated and entangled by needling. After that, the nonwoven fabric and the web blended layer are alternately laminated and entangled by needling, so that a total of eight layers are laminated. Next, 120g from the back of the base cloth
/ m ² of the web-blended layer was laminated and entangled by needling. Next, the surface of the web located on the front side of the base cloth is made of polyurethane-based polyelastomer.
A 25 g / m ² nonwoven fabric (melt blow method) was laminated and entangled by needling. Finally, the needling of the whole was performed to achieve the entanglement and integration of the whole felt. The felt having completed the entanglement was pressed by a hot roll from the surface while being stretched by a dryer, and heat-set with hot air to obtain a felt for papermaking.

Example 12 On the same base cloth as in Example 11, a short fiber of nylon 66 was used.
A 120 g / m ² single layer of nylon and a 120 g / m ² nonwoven fabric (melt blow method) composed of a polyurethane-based polyelastomer were alternately laminated and entangled by needling to obtain a felt for papermaking. However, the nonwoven fabric made of the polyurethane-based polyelastomer used above was embossed in advance to further improve the entanglement.

Comparative Example 3 Eight layers of only 120 g / m ² nylon single layer made of nylon 66 short fibers were laminated on the front side of a base fabric composed of warp monofilament twisted yarn and weft monofilament twisted yarn generally used for papermaking felt. Nylon on the back side of the base cloth
Only 120 g / m ² nylon single layer consisting of 66 short fibers
The layers were laminated and entangled by needling to form a web to obtain a papermaking felt.

Table 2 shows that each of the papermaking felts obtained in Examples 11 and 12 and Comparative Example 3 was subjected to a simulation test machine equipped with a pair of press rolls 4, a shower 5 and a suction box 6 as shown in FIG. The graph shows the results obtained by continuously spraying shower water without paper-making and running continuously at a felt running speed of 1000 m / min and a press roll pressure of 100 kg / cm for 300 hours.

As can be seen from Table 2, the felt for papermaking of Example 12 is given a higher degree of tightening than that of Comparative Example 3, so that the felt retains less water (moisture at the inlet and outlet of the press in Table 2) and has a lower surface. Is abraded (hair removal) because it is fixed by a hot press
The amount is small. Further, in Examples 11 and 12, since the elastic persistence of the polyelastomer is exhibited and the elastic persistence of the felt is good, the vertical vibration value of the press roll after the operation for a predetermined time is small.

Example 13 A nonwoven fabric of 120 g / m ^{2 made} of polyamide elastomer (melt blow method) and a short fiber of nylon 66 were used as a base fabric consisting of a warp monofilament twisted yarn and a weft multifilament twisted yarn as a felt for press of newspaper paper wet felt. Nylon single layers of 120 g / m ² were alternately laminated and entangled by needling. Laminating good thermal adhesion to web surface located on the front side of the base fabric, composite fibers (core polyester elastomer, sheath polyethylene elastomer) is excellent in mechanical durability of 25 g / m ² made of nonwoven fabric (meltblown method) It was entangled by needling. Finally, the needling of the whole was performed to achieve the entanglement and integration of the whole felt. The felt having completed the entanglement was pressed by a hot roll from the surface while being stretched by a dryer, and heat-set with hot air to obtain a felt for papermaking.

Comparative Example 4 In Example 13, a papermaking felt in which the web was made of only nylon 66 short fibers was obtained.

Table 3 shows the results of using the felts prepared in Example 13 and Comparative Example 4 in a newspaper press (transfer twin bar type) No. 3 press.

As can be seen from Table 3, the felt for papermaking of Example 13 is superior in elasticity persistence to that of Comparative Example 4, and is a felt with less water retention with tightness. It was found that the formation of paper was improved due to the good surface smoothness. Further, as for the good elasticity persistence, the vibration value in each direction of the press roll of the paper machine was remarkably improved as compared with Comparative Example 4, and stable paper making operation became possible.

[Effects of the Invention] As is apparent from the above description, the present invention has as a constituent component of the web part of the papermaking felt according to the present invention a web containing polyelastomer fibers and a web containing no polyelastomers fibers and a high-density polystyrene. Either one of a plurality of webs containing polyelastomer fibers and a web of a plurality of high-density polyelastomeric nonwoven fabrics alternately laminated, and the web surface of any web is used. After being entangled with the high-density nonwoven fabric (the uppermost layer on the front side of the base fabric) and then heat-sealed, the felt for papermaking exhibits the following specific effects.

That is, (a) as a result of the flexibility of the elastomer imparting softness to the felt, a soft felt that can be easily inserted into a paper machine is obtained.

(B) Since the nonwoven fabric having a high density is used, the web density of the felt is high, and the entanglement is good, so that the felt has low water retention, and thus the felt has good water squeezing.

(C) Since a polyelastomer (fiber and / or non-woven fabric) is used for the web, the elasticity of the felt is good, whereby the vibration value of the press roll of the paper machine is reduced and a stable papermaking operation is possible.

[Brief description of the drawings]

1 is a cross-sectional view of a papermaking felt showing one embodiment of the present invention, FIG. 2 is a cross-sectional view of a papermaking felt showing another embodiment, and FIG. 3 is a schematic explanatory view showing a simulation test machine. . 1 ... Base cloth, 2 ... Web, 2a ... Web blended layer, 2b ... Nylon single layer, 3 ... Polyelastomer nonwoven fabric, 3a ... Surface polyelastomer nonwoven fabric.

Claims (3)

(57) [Claims] 1. A papermaking felt in which a base fabric and a web are entangled and integrated, wherein the web contains polyelastomer fibers and a high-density nonwoven fabric of a high-density polyelastomer is heat-sealed to the surface of the web. Papermaking felt. 2. A papermaking felt in which a base fabric and a web are entangled and integrated, wherein a single high-density nonwoven fabric of a polyelastomer is interposed in the web, or a plurality of webs and the nonwoven fabric are alternately formed. A felt for papermaking, wherein a nonwoven fabric of high-density polyelastomer is heat-sealed on the surface of the web. 3. A papermaking felt in which a base fabric and a web are entangled and integrated, wherein the web contains polyelastomer fibers and one nonwoven fabric of high-density polyelastomer is interposed in the web, or A felt for papermaking, wherein a plurality of the webs and the nonwoven fabric are alternately laminated, and a high-density nonwoven fabric of a high-density polyelastomer is heat-sealed to the surface of the web.