JP2010116652A - Shoe press belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shoe press belts raising the compressive elasticity modulus of a prescribed region corresponding to a shoe edge part, and suppressing formation of cracks with little environmental effects when forming a reinforcing resin layer. <P>SOLUTION: The shoe press belt 1 includes: an inner peripheral layer 11; substrate layer 12; outer peripheral layer 13; and a pair of reinforcing resin layers 14. Furthermore, the pair of reinforcing resin layers are wound in the belt running direction, and disposed in prescribed regions E1 and E2 corresponding to the shoe edge part. The reinforcing resin layers are polyurethane layers containing a polyurethane obtained by curing a composition in which a urethane prepolymer is mixed with a curing agent. The urethane prepolymer is obtained by reacting a p-phenylene-diisocyanate compound with polytetramethylene glycol. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shoe press belt used in a papermaking shoe press apparatus, and more particularly to a shoe press belt used in a closed type shoe press.

A shoe press for papermaking uses a shoe press mechanism in which a loop-shaped shoe press belt is interposed between a press roll and a shoe. In this mechanism, dehydration is performed by passing a transport belt (or transport felt) and wet paper in a press section composed of a press roll and a shoe. The shoe press belt is used for dewatering by compressing the wet paper via a transport belt (or transport felt).
The shoe press belt is disposed between the press roll of the shoe press mechanism and the shoe and rotates. The dimension of the belt in the width direction (the weft direction: the CMD direction) is larger than the dimension of the shoe in the width direction (the weft direction).
Therefore, the belt can be divided into a belt center region that contacts the upper surface of the shoe, a shoe edge contact region, and a belt end region in the width direction. The shoe edge abutting portion region is a region located on the outer side in the width direction from the belt center region and undergoes bending deformation due to a strong load from the shoe edge portion on both sides in the width direction of the shoe. The belt end portion region is located outside the shoe edge contact portion region and is not in contact with the shoe.
Then, in a predetermined region that forms a part of the belt corresponding to the shoe edge portion (that is, the shoe edge contact portion region and the belt end region), compared to the belt central region in the belt width direction, Cracks often occur.

A general shoe press belt has a resin layer on the inner periphery and outer periphery of a base layer. Patent Document 1 (Japanese Patent Laid-Open No. 10-298893) describes a shoe press belt in which cracks at a predetermined portion corresponding to a shoe edge portion are hardly caused. In this belt, the hardness of the resin layer constituting the belt central region is increased, and the hardness of both edge regions in contact with the shoe edge portion is decreased.
Patent Document 2 (Japanese Patent Laid-Open No. 2005-97806) describes a technique for effectively suppressing the occurrence of cracks in a shoe press belt. This shoe press belt includes both end corresponding regions and a belt central region.
The both end corresponding regions are regions corresponding to both end portions in the width direction of the press roll or the shoe and having a small thickness. The belt center region is located between the both end corresponding regions and has a larger thickness than the both end corresponding regions.
Patent Document 3 (Japanese Patent Application Laid-Open No. 2008-111220) describes a papermaking shoe press belt having mechanical properties such as crack resistance. The polyurethane layer of this belt contains a polyurethane obtained from a composition in which a p-phenylene diisocyanate (paraphenylene diisocyanate (PPDI)) urethane prepolymer and a curing agent are mixed.

JP-A-10-298893 JP-A-2005-97806 JP 2008-1111220 A

In the shoe press belt described in Patent Document 1, the hardness of the resin layer is changed between the belt center region and both edge regions.
However, the resin component constituting the belt central region and the resin component constituting both edge regions are the same composition in which a tolylene diisocyanate (TDI) urethane prepolymer and a curing agent are mixed. As a result, the degree of improvement in crack resistance in both edge regions was not so high. Therefore, a technique for more effectively suppressing the generation of cracks has been demanded.

In the shoe press belt described in Patent Document 2, a process for forming the thickness corresponding to both ends corresponding to a small thickness and a polishing process for subsequent finishing are separately required.
In addition, since frictional heat is generated in these forming processes and polishing processes, there is a possibility that the resin layer of the belt may be altered and deteriorated by this frictional heat.

The polyurethane layer of the shoe press belt for papermaking described in Patent Document 3 has a composition in which a p-phenylene diisocyanate (PPDI) urethane prepolymer and a curing agent are mixed over the entire width direction of the belt. Polyurethane obtained from the product is used.
Therefore, in order to cure the composition and form a urethane layer of a shoe press belt having mechanical properties such as crack resistance, the environmental influence during curing (particularly in the process of manufacturing the belt, Adversely affected by temperature and humidity). Therefore, there has been a demand for a technology that is less susceptible to this environmental impact (adverse effects from the surrounding environment).

Conventionally, polyurethane obtained from a composition in which a tolylene diisocyanate (TDI) urethane prepolymer and a curing agent are mixed has been used for a shoe press belt.
In addition, a polyurethane obtained from a composition in which a 4,4′-methylenebis (phenylisocyanate) (MDI) urethane prepolymer and a curing agent are mixed has also been used for this shoe press belt.
These compositions were less susceptible to environmental influences (particularly adverse effects due to temperature and humidity in the belt manufacturing process) during curing.

Accordingly, the present inventors have developed a polyurethane obtained from a composition in which a p-phenylene-diisocyanate (PPDI) urethane prepolymer and a curing agent, which are susceptible to environmental influences, from a specific region (predetermined region) of the belt. I decided to use it limited to. In other areas (such as the belt center area), conventional polyurethane (that is, urethane that is not easily affected by temperature and humidity) is used. Thereby, this invention can solve the conventional subject.
That is, the object of the present invention is to increase the compression elastic modulus of a predetermined region that forms part of the shoe press belt corresponding to the shoe edge portion to reduce bending deformation and residual strain, thereby reducing cracks in the predetermined region. For shoe presses that can suppress the generation of styrene and use polyurethane obtained from a composition in which a p-phenylene-diisocyanate (PPDI) urethane prepolymer and a curing agent are mixed, only in the reinforcing resin layer Is to provide a belt.

In order to achieve the above-described object, a shoe press belt according to a first embodiment of the present invention is disposed between a press roll of a shoe press mechanism and a shoe below or above the shoe roll, and rotates. A resin inner peripheral layer in contact with the inner peripheral layer, a base layer provided on the outer periphery of the inner peripheral layer, and a resin outer peripheral layer formed on the outer periphery of the base layer. The shoe press belt is located in the width direction in a belt center region that is in contact with the shoe, on the outer side in the width direction from the belt center region, and corresponding to the shoe edge portions on both sides in the width direction of the shoe. It is divided into a pair of predetermined regions forming a part of the shoe press belt. The shoe press belt has a pair of reinforcing resin layers made of a polyurethane layer having a component different from that of the polyurethane layer in the belt central region. The pair of reinforcing resin layers are arranged around the pair of predetermined regions in the belt running direction (longitudinal direction).
The polyurethane layer constituting the reinforcing resin layer contains polyurethane obtained by curing a composition in which a urethane prepolymer (A) and a curing agent (B) are mixed. The urethane prepolymer (A) is obtained by reacting an isocyanate compound (a) containing 55 to 100 mol% of a p-phenylene-diisocyanate compound (PPDI) with a polytetramethylene glycol (b). It is a urethane prepolymer having an isocyanate group. The curing agent (B) is selected from the group consisting of 1,4-butanediol, hydroquinone bis-β hydroxyl ethyl ether, 3,5-diethyltoluenediamine, and 3,5-dimethylthiotoluenediamine.
Preferably, the polyurethane has an equivalent ratio (H / NCO) of the active hydrogen group (H) of the curing agent to the isocyanate group (NCO) of the urethane prepolymer of 0.88 <H / NCO. It is obtained by curing a composition in which the urethane prepolymer and the curing agent are mixed at a ratio of ≦ 1.0. This polyurethane preferably has a “JIS A hardness” of 92 to 99 degrees.

As described above, in the pair of reinforcing resin layers of the shoe press belt facing the wet paper, the urethane prepolymer material includes p-phenylene diisocyanate (PPDI), which easily forms a linear polymer, and polytetramethylene. Glycol is used.
That is, in the first embodiment, the p-phenylene-diisocyanate (PPDI) -based urethane prepolymer includes an isocyanate compound (a) containing 55 to 100 mol% of a p-phenylene-diisocyanate compound, and a polytetramethylene glycol (b And has an isocyanate group at the terminal.
The curing agent is composed of aliphatic 1,4-butanediol, hydroquinone bis-β-hydroxylethyl ether, 3,5-diethyltoluenediamine, and 3,5-dimethylthiotoluenediamine that easily form a linear polymer. A compound selected from the group is used.
By doing so, an excellent polyurethane is formed, so that a shoe press belt having mechanical properties such as crack resistance, bending fatigue resistance, and wear resistance can be obtained. The durability of the shoe press belt can be expected to be improved by 1.5 times or more than the durability of the shoe press belt conventionally used (usually about 2 to 3 months).

A shoe press belt according to a second embodiment of the present invention is disposed between a press roll of a shoe press mechanism and a shoe below or above the shoe, and rotates to travel, and is made of a resin inner circumference that contacts the shoe. A layer, a base layer provided on the outer periphery of the inner peripheral layer, and a resin outer peripheral layer formed on the outer periphery of the base layer. The shoe press belt is located in the width direction in a belt center region that is in contact with the shoe, on the outer side in the width direction from the belt center region, and corresponding to the shoe edge portions on both sides in the width direction of the shoe. It is divided into a pair of predetermined regions forming a part of the shoe press belt. The shoe press belt has a pair of reinforcing resin layers made of a polyurethane layer having a component different from that of the polyurethane layer in the belt central region. The pair of reinforcing resin layers are arranged around the pair of predetermined regions in the belt running direction.
The polyurethane layer constituting the reinforcing resin layer is a polyurethane obtained by curing a composition in which a urethane prepolymer (A) and a curing agent (B) having an active hydrogen group (H) are mixed. Is contained. The urethane prepolymer (A) is a urethane prepolymer obtained by reacting the isocyanate compound (a) with the polytetramethylene glycol (b) and having an isocyanate group at the terminal. The isocyanate compound (a) contains 55 to 100 mol% of an isocyanate compound selected from a p-phenylene-diisocyanate (PPDI) compound and 4,4′-methylenebis (phenyl isocyanate). The curing agent (B) contains 85 to 99.9 mol% of 1,4-butanediol and 15 to 0.1 mol% of the aromatic polyamine having the active hydrogen group (H). It is.
In this case, the aromatic polyamine having the active hydrogen group (H) is 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, 3,5-dimethylthio. Toluene-2,4-diamine, 3,5-dimethylthiotoluene-2,6-diamine, 4,4′-bis (2-chloroaniline), 4,4′-bis (sec-butylamino) -diphenylmethane, N, N′-dialkyldiaminodiphenylmethane, 4,4′-methylenedianiline, 4,4′-methylene-bis (2,3-dichloroaniline), 4,4′-methylene-bis (2-chloroaniline), An aromatic polyamine selected from 4,4′-methylene-bis (2-ethyl-6-methylaniline), trimethylene-bis (4-aminobenzoate) and phenylenediamine; It is a species or a mixture of two or more.

As described above, in the pair of reinforcing resin layers of the shoe press belt facing the wet paper, as the urethane prepolymer material (A), p-phenylene-diisocyanate (PPDI) that easily forms a linear polymer, and Polytetramethylene glycol can be used.
That is, in the second embodiment, the p-phenylene-diisocyanate (PPDI) urethane prepolymer is obtained by reacting the isocyanate compound (a) with the polytetramethylene glycol (b), and has an isocyanate group at the terminal. The isocyanate compound (a) contains 55 to 100 mol% of an isocyanate compound selected from a p-phenylene-diisocyanate (PPDI) compound and 4,4′-methylenebis (phenylisocyanate). ing.
In addition, as the curing agent (B) having an active hydrogen (H) group, aliphatic 1,4-butanediol that easily forms a linear polymer is used as a main component, and an aromatic polyamine compound is used as a dependent component. can do.
Thereby, since the urethane prepolymer made from p-phenylene-diisocyanate absorbs moisture in the air, the wear resistance of the polyurethane does not deteriorate.
Because it is a polyurethane with much higher abrasion resistance than polyurethane obtained by using 1,4-butanediol alone, mechanical properties such as abrasion resistance, crack resistance, and bending fatigue resistance are high even if the hardness is high. An excellent shoe press belt can be obtained.
In particular, an aromatic polyamine compound as a dependent component used in combination with an aliphatic 1,4-butanediol as a curing agent can improve wear resistance without lowering the “JIS A hardness” of the obtained polyurethane. Therefore, the durability of the shoe press belt of the present invention can be expected to be improved by a factor of two or more compared to the durability of shoe press belts currently used (usually about 2 to 3 months).

  The polyurethane layer constituting the reinforcing resin layer contains polyurethane obtained by curing a composition in which a urethane prepolymer and a curing agent are mixed. The urethane prepolymer may be obtained by reacting a p-phenylene-diisocyanate compound and a polyol. In this case, the curing agent may be selected from the group consisting of aliphatic diols and aromatic diamines. The polyol is polytetramethylene glycol, and the aliphatic diol of the curing agent is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, and 1,6-hexanediol, Even if the aromatic diamine of the curing agent is selected from the group consisting of 3,5-dimethylthiotoluenediamine, methylenebisorthochloroaniline and 3,3′-dichloro-4,4′-diaminodiphenylmethane. Good.

In the present invention, it is preferable that the reinforcing resin layer is fixed to and integrated with at least the outer peripheral layer and is exposed to the outer peripheral surface side.
Preferably, the reinforcing resin layer is integrally fixed only to the outer peripheral layer, the case where the reinforcing resin layer is integrally fixed from the outer peripheral layer to the base layer, and the base layer to the base body. This is one configuration selected from the group consisting of the case where the inner peripheral layer is fixed to the inner peripheral layer through the layer, and the case where the inner peripheral layer is integrally fixed.
Preferably, the predetermined region forming a part of the shoe press belt is located on the outer side in the width direction with respect to the belt center region and a shoe edge contact portion region that contacts the shoe edge portion, and the shoe edge contact. A region including a belt end region including an end portion in a weft direction orthogonal to the belt traveling direction, and the reinforcing resin layer includes the shoe edge contact region. And the belt end region.
The predetermined region forming a part of the shoe press belt is a shoe edge contact portion region that is located on the outer side in the width direction from the belt central region and contacts the shoe edge portion, and the reinforcing resin The layer may be disposed only in the shoe edge contact portion region.
Moreover, the recessed part extended in the said belt running direction can also be formed in the surface of the resin layer for reinforcement.
The shoe press belt further includes a resin intermediate layer in which the base layer is embedded, and the inner peripheral layer and the outer peripheral layer are laminated on an inner periphery and an outer periphery of the intermediate layer, respectively. The entire layer is preferably at least a three-layer structure.

Since the shoe press belt according to the present invention is configured as described above, the bending elastic force and the residual strain are increased by increasing the compression elastic modulus in a predetermined region that forms part of the shoe press belt corresponding to the shoe edge portion. Less. Thereby, generation | occurrence | production of the crack in this predetermined area | region can be suppressed. Further, the durability of the entire belt can be improved by improving the bending fatigue resistance and wear resistance in the predetermined region.
Also, polyurethane obtained from a composition in which a p-phenylene-diisocyanate (PPDI) urethane prepolymer and a curing agent are mixed can be used only for the reinforcing resin layer. Therefore, the environmental influence at the time of hardening the said composition can be decreased.

The polyurethane layer constituting the shoe press belt is usually a composition in which a tolylene diisocyanate (TDI) urethane prepolymer and a curing agent are mixed, or 4,4′-methylenebis (phenylisocyanate) (MDI). A polyurethane obtained from a composition in which a urethane prepolymer and a curing agent are mixed has been used.
However, it has been difficult for this urethane to adjust both the crack resistance and the wear resistance in a well-balanced manner. That is, a polyurethane layer made of a TDI urethane prepolymer is excellent in wear resistance, but in order to improve crack resistance, it is necessary to sacrifice the wear resistance to some extent.
On the other hand, a polyurethane layer made of an MDI urethane prepolymer is excellent in crack resistance, but it has been necessary to sacrifice crack resistance to some extent in order to improve wear resistance.
That is, since the polyurethane layer of the conventional shoe press belt uses the same polyurethane, it is difficult to simultaneously improve both the crack resistance and the wear resistance.

Therefore, the shoe press belt of the present invention includes a pair of reinforcing resin layers made of a polyurethane layer having a component different from that of the polyurethane layer in the central region of the belt. That is, the urethane prepolymer in the belt center region E and the urethane prepolymer of the reinforcing resin layer in predetermined regions (for example, the shoe edge contact region E1 and the belt end region E2) have different components.
For the polyurethane layer in the belt center region E, polyurethane conventionally used for shoe press belts for papermaking is used. This polyurethane is a polyurethane obtained from a composition in which a tolylene diisocyanate (TDI) urethane prepolymer and a curing agent are mixed, or a 4,4′-methylenebis (phenylisocyanate) (MDI) urethane prepolymer and a curing agent. Is a polyurethane obtained from a mixed composition.
The belt center area E occupies a large proportion of the entire width of the belt, and is not easily affected by temperature and humidity in these areas. The belt center region E is preferably a polyurethane layer made of a TDI urethane prepolymer having high wear resistance.

On the other hand, the polyurethane layer of the reinforcing resin layer in the predetermined area (the shoe edge contact area E1 and the belt end area E2) has both crack resistance and wear resistance characteristics, particularly crack resistance. Polyurethane obtained from a composition in which a p-phenylene diisocyanate (PPDI) urethane prepolymer and a curing agent, which are resistant to heat, are mixed is used.
The composition is easily affected by temperature and humidity during curing, but is limited to a specific region (reinforcing resin layer) of the belt. Therefore, the adverse effect is small, and the durability of the entire belt can be improved by improving the bending fatigue resistance and wear resistance of the belt in the predetermined region.

In the shoe press belt having the above-described configuration, the compression elastic modulus of the predetermined regions (the shoe edge contact portion region E1 and the belt end portion region E2) forming a part of the shoe press belt corresponding to the shoe edge portion is increased. Bending deformation and residual strain are reduced. As a result, the occurrence of cracks in this predetermined region can be suppressed.
Further, a urethane layer obtained from a composition in which a p-phenylene-diisocyanate (PPDI) urethane prepolymer and a curing agent are mixed is formed only on the reinforcing resin layer. Therefore, there is little environmental influence at the time of hardening a polyurethane layer.
Furthermore, since the bending fatigue resistance and wear resistance in a predetermined region of the shoe press belt are improved, the durability of the entire belt can be improved.

Hereinafter, various embodiments according to the present invention will be described with reference to the drawings.
1 to 5H are diagrams showing an embodiment of the present invention. 1 and 2 are a perspective view and a cross-sectional view showing a schematic configuration of the shoe press mechanism, respectively, and FIG. 3 is a lateral cross-sectional view of a press portion in the shoe press mechanism of FIG.
4A is a sectional view of a shoe press belt, FIG. 4B is an enlarged sectional view of a portion IV in FIG. 4A, and FIG. 4C is an enlarged sectional view corresponding to FIG. 5A to 5H are sectional views of shoe press belts according to various modifications.

As shown in FIGS. 1 to 3, a shoe press mechanism 4 is used in a shoe press for papermaking. The shoe press mechanism 4 includes a press roll 2, a shoe 3, and a loop-shaped shoe press belt (hereinafter referred to as a belt) 1, 1a to 1h (FIGS. 4A to 5H).
The shoe 3 is disposed below or above the press roll 2. The belts 1, 1 a to 1 h are disposed between the press roll 2 and the shoe 3, and rotate so that the inner peripheral surface of the belt contacts the shoe 3. In the shoe press mechanism 4, dehydration is performed by passing the transport felt 6 and the wet paper web 7 in the press section 5 constituted by the press roll 2 and the shoe 3.

Belts 1, 1 a to 1 g shown in FIGS. 4A to 5G are made of a resin-made inner peripheral layer 11 that contacts the shoe 3, a base layer 12 provided on the outer periphery of the inner peripheral layer 11, and the base layer 12. And a resin outer peripheral layer 13 formed on the outer periphery.
A belt 1h shown in FIG. 5H includes an inner peripheral layer 11, a base layer 12, and an outer peripheral layer 13, and further includes an intermediate layer 18 made of resin. Since the inner peripheral layer 11 and the outer peripheral layer 13 are respectively laminated on the inner periphery and the outer periphery of the intermediate layer 18, the entire resin layer has at least a three-layer structure. The base layer 12 is embedded in the intermediate layer 18.

In belts 1 and 1a to 1h shown in FIGS. 4A to 5H, the base layer 12 is made of a fiber base material. As the fiber base material, woven fabric, knitted fabric, non-woven fabric, lattice-shaped material, or the like can be used. As an example, a woven fabric woven with a warp double weave structure is used for the base fabric constituting the base layer 12. Nylon monofilament single yarn and twisted yarn are used for warp and weft of this fabric.
The inner peripheral layer 11 and the outer peripheral layer 13 (in the belt 1h, the inner peripheral layer 11, the outer peripheral layer 13, and the intermediate layer 18) are constituted by a polyurethane layer containing polyurethane. The base layer 12 is embedded in this polyurethane layer.
As an example, a TDI urethane prepolymer (made by Mitsui Chemicals) obtained by reacting tolylene diisocyanate (TDI) and polytetramethylene glycol (PTMG), and a curing agent (for example, 1,4-butanediol) To obtain a composition. This composition is thermally cured to form each polyurethane layer of the inner peripheral layer 11, the outer peripheral layer 13, and the intermediate layer 18.

The belts 1, 1 a to 1 h are located in the press unit 5 between the shoe 3 and the conveying felt 6 that supports the wet paper 7, and the inner peripheral surface of the belt contacts the shoe 3, so Travel in the direction: MD direction). The dimension (belt weft dimension W1) in the width direction (wet direction: CMD direction) of the belt is larger than the dimension (shoe lateral dimension W2) in the width direction (lattice direction) of the shoe 3.
Accordingly, the belts 1, 1a to 1h are placed in a state in which the weft direction end portions 20 (FIG. 3) on both sides thereof extend outward. The inner peripheral surfaces of the belts 1, 1 a to 1 h are in contact with the upper surface 9 of the shoe 3 between the shoe edge portion 8 on one side in the weft direction and the shoe edge portion 8 on the other side.

As a result, the belts 1, 1 a to 1 h are divided into a belt central region E that contacts the upper surface 9 of the shoe 3 and a pair of predetermined regions in the width direction. The pair of predetermined regions are located on the outer side in the width direction from the belt center region E, and form part of the belts 1, 1 a to 1 h corresponding to the shoe edge portions 8 on both sides in the width direction of the shoe 3.
The pair of predetermined regions includes at least a pair of shoe edge contact portion regions E1 that are located on the outer side in the width direction from the belt center region E and contact the shoe edge portion 8. In addition, the pair of predetermined regions usually includes a pair of belt end regions E2. The belt end region E2 includes an end portion 20 in the weft direction that is located on the outer side in the width direction from the shoe edge contact portion region E1 and is orthogonal to the running direction (longitudinal direction) of the belts 1 and 1a to 1h. .

In the belt center region E, the inner peripheral surfaces of the belts 1, 1 a to 1 h are in contact with the upper surface 9 of the shoe 3. The shoe edge portion 8 is located in the shoe edge contact portion region E1.
Therefore, the inner peripheral surfaces of the belts 1, 1 a to 1 h in the shoe edge contact portion region E 1 are in contact with the upper surface 9 of the shoe 3 at the center side of the shoe edge portion 8, but are not in contact outside the shoe edge portion 8. . Since there is no shoe 3 in the belt end region E2, the inner peripheral surfaces of the belts 1, 1a to 1h are not in contact with the shoe 3 in this region E2.

The belts 1, 1 a to 1 h have a pair of reinforcing resin layers 14 and 14 a to 14 h made of a polyurethane layer having a component different from that of the polyurethane layer in the belt center region E. The pair of reinforcing resin layers 14, 14 a to 14 h are arranged around the pair of predetermined regions described above in the belt running direction (warp direction).
The pair of reinforcing resin layers 14 and 14a to 14h are fixed to and integrated with at least the outer peripheral layer 13, and are exposed on the outer peripheral surface 15 side.

The “predetermined region forming part of the shoe press belt” includes a shoe edge contact portion region E1 that contacts the shoe edge portion 8, and a weft-direction end perpendicular to the belt running direction (longitudinal direction). This is a region including the end region E2.
In the belts 1, 1 a to 1 e, 1 g and 1 h in this case, the reinforcing resin layers 14, 14 a to 14 e, 14 g and 14 h are arranged in both the shoe edge contact region E1 and the belt end region E2. (FIGS. 4A, 5A to 5E, 5G, and 5H).
In the belt 1f according to a modification to this, the reinforcing resin layer 14f is disposed only in the shoe edge contact portion region E1 that contacts the shoe edge portion 8 (FIG. 5F). Accordingly, the “predetermined region forming part of the shoe press belt” in this case is the shoe edge contact portion region E1.
As described above, the “predetermined region” includes both the shoe edge contact region E1 and the belt end region E2, and only the shoe edge contact region E1.

  In the belts 1 and 1a to 1h, the pair of reinforcing resin layers 14 and 14a to 14h in a predetermined region located on the outer side in the width direction from the belt central region E are configured by a polyurethane layer containing polyurethane.

In the first embodiment, the polyurethane layers obtained by curing the composition in which the urethane prepolymer (A) and the curing agent (B) are mixed are contained in the polyurethane layers of the reinforcing resin layers 14 and 14a to 14h. Has been.
The urethane prepolymer (A) is obtained by reacting an isocyanate compound (a) containing 55 to 100 mol% of a p-phenylene-diisocyanate compound with polytetramethylene glycol (b), and has an isocyanate group at the terminal. It is a urethane prepolymer.
The curing agent (B) is selected from the group consisting of 1,4-butanediol, hydroquinone bis-β hydroxyl ethyl ether, 3,5-diethyltoluenediamine, and 3,5-dimethylthiotoluenediamine.

Preferably, the polyurethane forming the reinforcing resin layers 14, 14a to 14h is an equivalent ratio (H / NCO) of the active hydrogen group (H) of the curing agent (B) and the isocyanate group (NCO) of the urethane prepolymer. Is obtained by curing a composition in which a urethane prepolymer and a curing agent are mixed at a ratio of 0.88 <H / NCO ≦ 1.0.
Preferably, the polyurethane has a “JIS A hardness” of 92 to 99 degrees (preferably 95 to 99 degrees).

The isocyanate compound (a) as a raw material for the urethane prepolymer (A) contains 55 to 100 mol% (preferably 75 mol% or more) of p-phenylene-diisocyanate (PPDI) in the isocyanate compound.
As isocyanate compounds other than PPDI, 2,4-tolylene-diisocyanate (2,4-TDI), 2,6-tolylene-diisocyanate (2,6-TDI), 4,4′-methylenebis (phenylisocyanate) (MDI) ) And 1,5-naphthylene-diisocyanate (NDI) can be used in an amount of 45 mol% or less (preferably 25 mol% or less).

The polyol is a raw material for the urethane prepolymer (A). This polyol can be used as long as it contains 65 to 100 mol% (preferably 85 mol% or more) of polytetramethylene glycol (PTMG) in the polyol.
Polyols other than PTMG include polyoxypropylene glycol (PPG), polyethylene adipate (PEA), polycaprolactone diol (PCL), trimethylolpropane (TMP), and polycarbonate diol (PCD), and the content of the polyol is 35 mol% or less. If it is contained in an amount of (preferably 15 mol% or less), it can be used in combination.
The polycarbonate diol refers to C6-homo-polycarbonate diol, C6 / C5 carbonate diol copolymer, and C6 / C4 carbonate diol copolymer.

The curing agent that can be used is selected from the group consisting of 1,4-butanediol, hydroquinone bis-β hydroxyl ethyl ether, 3,5-diethyltoluenediamine and 3,5-dimethylthiotoluenediamine.
Further, this curing agent may be used in combination with another curing agent such as 4,4′-methylenedianiline (MDA), 4,4′-methylene-bis- (2-chloroaniline) (MOCA). . In this case, the ratio of the other curing agent is 15 mol% or less.

In the second embodiment, a urethane prepolymer (A) and a curing agent (B) having an active hydrogen group (H) are mixed in the polyurethane layer forming the reinforcing resin layers 14 and 14a to 14h. A polyurethane obtained by curing the prepared composition is contained.
The urethane prepolymer (A) is a urethane prepolymer obtained by reacting the isocyanate compound (a) with the polytetramethylene glycol (b) and having an isocyanate group at the terminal.
The isocyanate compound (a) contains 55 to 100 mol% of an isocyanate compound selected from p-phenylene-diisocyanate compound (PPDI) and 4,4′-methylenebis (phenyl isocyanate). The curing agent (B) contains 85 to 99.9 mol% of 1,4-butanediol and 15 to 0.1 mol% of the aromatic polyamine having the active hydrogen group (H). It is.
In this case, the aromatic polyamine having the active hydrogen group (H) is 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, 3,5-dimethylthio. Toluene-2,4-diamine, 3,5-dimethylthiotoluene-2,6-diamine, 4,4′-bis (2-chloroaniline), 4,4′-bis (sec-butylamino) -diphenylmethane, N, N′-dialkyldiaminodiphenylmethane, 4,4′-methylenedianiline, 4,4′-methylene-bis (2,3-dichloroaniline), 4,4′-methylene-bis (2-chloroaniline), An aromatic polyamine selected from 4,4′-methylene-bis (2-ethyl-6-methylaniline), trimethylene-bis (4-aminobenzoate) and phenylenediamine; It is a species or a mixture of two or more.

In the polyurethane layer forming the reinforcing resin layers 14 and 14a to 14h facing the wet paper, a composition in which the urethane prepolymer (A) and the curing agent (B) are mixed is obtained at 70 to 140 ° C. at 2 to 2. Polyurethane obtained by heat curing for 20 hours is preferably contained.
The urethane prepolymer (A) and the curing agent (B) have an equivalent ratio (H) of active hydrogen groups (H) of the curing agent (B) and isocyanate groups (NCO) of the urethane prepolymer (A). / NCO) is mixed at a ratio of 0.88 ≦ H / NCO ≦ 1.12.
The urethane prepolymer (A) comprises an isocyanate compound (a) containing 55 to 100 mol% of an isocyanate selected from p-phenylene-diisocyanate (PPDI) and 4,4′-methylenebis (phenylisocyanate); It is obtained by reacting with methylene glycol (b) and has an isocyanate group at the terminal.
The curing agent (B) contains 85 to 99.9 mol% of 1,4-butanediol and 15 to 0.1 mol% of an aromatic polyamine having an active hydrogen group (H).

Originally, the terminal NCO group of the urethane prepolymer (A) obtained by using 55 to 100 mol% of p-phenylene diisocyanate (PPDI) as the main component of the isocyanate compound easily absorbs moisture in the atmosphere. It must react with the curing agent in a sealed system that is not affected by moisture.
On the other hand, in the polyurethane layer forming the reinforcing resin layers 14 and 14a to 14h, moisture at the time of curing the urethane prepolymer is obtained by using an aromatic polyamine as a subordinate component of the 1,4-butanediol curing agent. The influence of is suppressed.
As a result, this polyurethane layer has excellent wear resistance, crack resistance, and bending fatigue resistance despite being a polyurethane having a “JIS A hardness” of 92 to 100 degrees (preferably 95 to 100 degrees). To demonstrate.

The isocyanate compound (a) is a raw material for the urethane prepolymer (A). As the isocyanate compound (a), an isocyanate compound selected from p-phenylene-diisocyanate (PPDI) and 4,4′-methylenebisphenyl isocyanate (MDI) as main components is added to 55-55 in the isocyanate compound (a). If it contains 100 mol% (preferably 75 mol% or more), it can be used.
As isocyanate compounds other than PPDI and MDI, 2,4-tolylene-diisocyanate (2,4-TDI), 2,6-tolylene-diisocyanate (2,6-TDI), 1,5-naphthalene-diisocyanate ( NDI). These isocyanate compounds can be used in combination with the isocyanate compound (a) as long as they are contained in the isocyanate compound (a) in an amount of 45 mol% or less (preferably 25 mol% or less).

  The proportion of linear molecules of p-phenylene diisocyanate (PPDI) and 4,4′-methylenebisphenyl isocyanate (MDI) in the isocyanate compound (a) may be less than 55 mol%. In this case, it is difficult to significantly improve the hardness, crack resistance and wear resistance of the obtained polyurethane.

The polyol is a raw material for the urethane prepolymer (A). This polyol can be used as long as it contains 65 to 100 mol% (preferably 85 mol% or more) of polytetramethylene glycol (PTMG) (b) in the polyol.
As polyols other than PTMG, polyoxypropylene glycol (PPG), polyethylene adipate (PEA), polycaprolactone diol (PCL), trimethylolpropane (TMP) and the like are 35 mol% or less (preferably 15 mol) in the polyol. % Or less) can be used together.

As the main component of the curing agent (B), 1,4-butanediol as a linear molecule is contained in 85 to 99.9 mol% (preferably 90 to 99.5 mol%).
The aromatic polyamine having an active hydrogen group (H) is a dependent component of the curing agent (B). Examples of the aromatic polyamine include 3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine mixture (trade name ETHACURE100), 4,4′-bis (2-chloroaniline). ), 3,5-dimethylthiotoluene-2,4-diamine and 3,5-dimethylthiotoluene-2,6-diamine mixture (trade name ETHACURE300), 4,4′-bis (sec-butylamino) -diphenylmethane N, N′-dialkyldiaminodiphenylmethane, 4,4′-methylenedianiline (MDA), 4,4′-methylene-bis (2,3-dichloroaniline) (TCCAM), 4,4′-methylene-bis (2-chloroaniline) (MOCA), 4,4'-methylene-bis (2-ethyl-6-methylaniline) (trade name CUREHARD MED), trimethylene-bis (4-aminobenzo) 1) or more than one aromatic polyamine having a molecular weight of 108 to 380 (preferably a molecular weight of 198 to 342), selected from m-phenylenediamine (MPDA) A mixture is used together in the ratio of 15-0.1 mol% (preferably 10-0.5 mol%) in a hardening | curing agent (B).
When the aromatic polyamine in the curing agent (B) is less than 0.1 mol%, the improvement in the abrasion resistance of the polyurethane is low, and when it is 15 mol% or more, the improvement in the bending resistance is low as compared with a commercially available product.

  As described above, p-phenylene-diisocyanate constituting the urethane prepolymer of the reinforcing resin layers 14 and 14a to 14h is a polymer whose molecular structure extends linearly and easily forms a linear polymer. Excellent wear resistance and flex resistance, and exhibits strong crack resistance.

In another embodiment, the urethane prepolymer is obtained by reacting a p-phenylene-diisocyanate (PPDI) compound and a polyol, and the curing agent is selected from the group consisting of aliphatic diols and aromatic diamines. It may be the case.
In this case, the above-mentioned polyol is polytetramethylene glycol (PTMG), and the aliphatic diol of the above-mentioned curing agent is from the group consisting of 1,4-butanediol, 1,3-propanediol and 1,6-hexanediol. It may be the case where it is selected.
The aromatic diamine of the above-mentioned curing agent is selected from the group consisting of 3,5-dimethylthiotoluenediamine, methylenebisorthochloroaniline (MBOCA), and 3,3′-dichloro-4,4′-diaminodiphenylmethane. It may be the case.
The curing agent may be a diamine curing agent such as 3,5-dimethylthiotoluenediamine (AMTDA) or methylenebisorthochloroaniline (MBOCA).
In addition, 3,5-dimethylthiotoluenediamine has various isomers depending on the substitution positions of the dimethylthio group and amino group, and is used in the form of a mixture of these isomers. This isomer mixture is available as ETHACURE300 (trade name) manufactured by Albemarle, USA.

The polyurethane used for the portions other than the reinforcing resin layers 14 and 14a to 14h (that is, the belt central region E and / or the inner peripheral layer 11) is a mixture of tolylene diisocyanate (TDI) urethane prepolymer and a curing agent. Or a composition in which a 4,4′-methylenebis (phenylisocyanate) (MDI) -based urethane prepolymer and a curing agent are mixed.
As these urethane prepolymers, one of a TDI urethane prepolymer and an MDI urethane prepolymer is appropriately selected. The TDI urethane prepolymer is obtained by reacting tolylene diisocyanate (TDI) with polytetramethylene glycol (PTMG). The MDI urethane prepolymer is obtained by reacting 4,4′-methylenebis (phenylisocyanate) (MDI) with polytetramethylene glycol (PTMG).

As an embodiment of the present invention, a large number of grooves 16 for drainage are formed on the surface (outer peripheral surface 15) of the outer peripheral layer 13 of the belts 1, 1a to 1h. The water squeezed out from the wet paper 7 during the above-described pressing is held in the groove 16. The water held in the groove 16 is discharged to the outside of the press unit 5 by the rotation of the belts 1, 1 a to 1 h at the outlet of the press unit 5.
In the belt 1 of FIG. 4B, many grooves 16 are formed in the belt center region E of the outer peripheral layer 13, and no grooves 16 are formed in the reinforcing resin layer 14. As a modification of the present embodiment, grooves 16 can be formed on both the surface of the outer peripheral layer 13 and the surface of the reinforcing resin layer 14 (FIG. 4C).
A large number of land portions (convex portions) 17 are formed between the large number of grooves 16 to constitute the belt outer peripheral surface 15. The convex portion 17 is in direct contact with the conveying felt 6 and the groove 16 is a drainage channel.

Since the belts 1 and 1a to 1h of the present invention are provided with the pair of reinforcing resin layers 14 and 14a to 14h, the compression elastic modulus of the belts 1 and 1a to 1h is increased, and bending deformation and residual strain are reduced. . Therefore, surface abrasion and crack generation of the reinforcing resin layers 14 and 14a to 14h are suppressed, and when the groove 16 is provided in the reinforcing resin layer, generation of cracks in the groove 16 can be suppressed.
That is, the pair of reinforcing resin layers 14, 14 a to 14 h circulate in the warp direction (MD direction) in predetermined regions that form part of the belt corresponding to the shoe edge portions 8 on both sides in the width direction of the shoe 3. Are arranged.
Therefore, the compression elastic modulus of the belt portion in the predetermined region corresponding to the shoe edge portions 8 on both sides in the width direction of the shoe 3 is increased. At the same time, the belt portion in the predetermined region has less bending deformation and residual strain. As a result, it is possible to improve the durability of the belts 1, 1a to 1h by suppressing the occurrence of surface wear and cracks in the predetermined region.

  The pair of reinforcing resin layers 14, 14 a to 14 h are integrally fixed only to the outer peripheral layer 13, when fixed integrally from the outer peripheral layer 13 to the base layer 12, and from the outer peripheral layer. The structure is one selected from the group consisting of the case in which the inner layer 11 is fixed to the inner peripheral layer 11 through the base layer 12.

In the belt 1 shown in FIGS. 4A to 4C, the pair of reinforcing resin layers 14 are integrally fixed only to the outer peripheral layer 13. In the belts 1, 1a, and 1c shown in FIGS. 5A, 5B, and 5C, a pair of reinforcing resin layers 14a, 14b, and 14c are integrally fixed from the outer peripheral layer 13 to the base layer 12.
In the belt 1 a shown in FIG. 5A, the reinforcing resin layer 14 a does not penetrate into the base layer 12 and is disposed up to the outer peripheral surface of the base layer 12.
In the belt 1b shown in FIG. 5B, the reinforcing resin layer 14b penetrates into the inside of the base layer 12 having the thickness c, and penetrates to a part of the thickness d of the entire thickness c of the base layer 12. .
In the belt 1c shown in FIG. 5C, the reinforcing resin layer 14c penetrates up to the entire thickness of the base layer 12 (that is, up to the thickness c).
In the belt 1d shown in FIG. 5D, a pair of reinforcing resin layers 14d are integrally fixed from the outer peripheral layer 13 to the middle of the inner peripheral layer 11 through the base layer 12. In the belt 1e shown in FIG. 5E, a pair of reinforcing resin layers 14e are integrally fixed from the outer peripheral layer 13 through the base layer 12 to the entire inner peripheral layer 11.

In this manner, the pair of reinforcing resin layers 14 and 14a to 14h can be freely selected so as to have an arbitrary configuration in the thickness direction of the belts 1 and 1a to 1h.
Therefore, the present invention can easily cope with a function required for a predetermined area corresponding to the shoe edge portions 8 on both sides in the width direction of the shoe 3. That is, by adjusting the degree of increasing the compression elastic modulus to reduce bending deformation and residual strain, it is possible to suppress the occurrence of wear and cracks in a predetermined region of the belt.
Further, only the reinforcing resin layers 14 and 14a to 14h form a polyurethane layer obtained from a composition in which a p-phenylene-diisocyanate (PPDI) urethane prepolymer and a curing agent are mixed. Therefore, the environmental influence at the time of hardening the said composition can be decreased.

In the belts 1, 1a to 1e, 1g, and 1h shown in FIGS. 4A to 4C, 5A to 5E, and 5H, the inner peripheral surface of the belt is a shoe. It is disposed in both the shoe edge contact region E1 that contacts the edge 8 and the belt end region E2 that includes the weft direction end of the belt.
In this way, when the reinforcing resin layers 14, 14a to 14e, 14g, and 14h are formed, the region (width) of the reinforcing resin layer is slightly widened, but the forming operation is easily performed. Can do. Since the ratio of the region (width) of the reinforcing resin layer to the entire belt width is small, the environmental impact when forming the reinforcing resin layer can be small.

  In the belt 1f shown in FIG. 5F, the reinforcing resin layer 14f is disposed only in the shoe edge contact portion region E1 where the inner peripheral surface of the belt contacts the shoe edge portion 8. In this way, the work of forming the reinforcing resin layer 14 is somewhat troublesome, but the region of the reinforcing resin layer 14f can be formed further narrowly.

In the belt 1g shown in FIG. 5G, a pair of recesses 30 extending in the warp direction are formed on the surfaces of the pair of reinforcing resin layers 14g. The pair of recesses 30 are disposed only in the shoe edge contact part region E1. The pair of recesses 30 may be formed so as to be wide from the shoe edge contact part region E1 to the belt end part region E2.
By forming the concave portion 30 extending in the warp direction, the water dehydrated by the press portion 5 flows out in the width direction from the central region E of the outer peripheral layer 13 along the predetermined region, and is further discharged through the concave portion 30. Is done. As a result, it is not necessary to form a large number of grooves 16 (FIGS. 4B and 4C) on the inner surface of the recess 30.
Since the groove 16 that is likely to be the starting point of cracks can be eliminated, the reinforcing resin layer 14g can more effectively suppress the occurrence of cracks. Moreover, it becomes easy to discharge the water squeezed out of the wet paper 7 during pressing.

In the belt 1h shown in FIG. 5H, the resin layer in the belt center region E has a three-layer structure including the inner peripheral layer 11, the intermediate layer 18, and the outer peripheral layer 13. In addition, a reinforcing resin layer 14h is disposed in the shoe edge contact part region E1 and the belt end part region E2. Therefore, the resin layers in the regions E1 and E2 have a four-layer structure including the inner peripheral layer 11, the intermediate layer 18, the outer peripheral layer 13, and the reinforcing resin layer 14h. Further, the base layer 12 is embedded in the intermediate layer 18 to reinforce the intermediate layer 18.
Therefore, a resin different from the resin of the inner peripheral layer 11 and the outer peripheral layer 13 can be selected for the base layer 12. As a result, a resin having a function different from that required for the inner peripheral layer 11 and the outer peripheral layer 13 (for example, a resin that strongly reinforces the base layer 12) or the like can be selected as appropriate.

Next, experimental results comparing the belt of the present invention and a conventional belt will be described.
FIG. 6 is a cross-sectional view of a conventional belt 100, and FIG. 7 is a table showing experimental data of the first embodiment. 8 and 9 are tables showing the second embodiment, and the entire experimental data are shown in both figures. FIG. 10 is a schematic diagram of an experimental apparatus 110 for examining crack resistance, and FIG. 11 is a table showing the experimental results.
The conventional belt 100 shown in FIG. 6 includes an inner peripheral layer 11, a base layer 12, and an outer peripheral layer 13, but no reinforcing resin layer is formed. The inner peripheral layer 11 and the outer peripheral layer 13 of the belt 100 are made of polyurethane resin.

  Next, in order to evaluate the physical properties of the polyurethane forming the reinforcing resin layers 14 and 14a to 14h of the belt with respect to the first embodiment, a case where a polyurethane test piece is manufactured is shown in Reference Examples 1 to 6 in FIG. explain.

(Reference Example 1)
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG). The urethane prepolymer thus obtained (NCO% is 5.51%, viscosity at 55 ° C. is 1,800 cps, preheating temperature is 66 ° C.) and 1,4-butanediol (H / NCO ratio is 0). .95) is poured into a preheated mold, heated to 127 ° C. and precured at 127 ° C. for 0.5 hours.
Thereafter, the precured composition is removed from the mold and further postcured at 127 ° C. for 16 hours. As a result, a cured polyurethane sheet having a “JIS A hardness” of 98.1 degrees is obtained. A test piece (thickness: 1.5 mm) was produced from this sheet.

(Reference Example 2)
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG). The urethane prepolymer thus obtained (NCO% is 5.51%, viscosity at 55 ° C. is 1,800 cps, preheating temperature is 120 ° C.) and hydroquinone bis-β-hydroxyethyl ether (H / NCO ratio is 0.95) is poured into a preheated mold, heated to 127 ° C. and precured at 127 ° C. for 0.5 hours. The precured composition is then postcured at 127 ° C. for 16 hours.
As a result, a cured polyurethane sheet having a “JIS A hardness” of 98.1 degrees is obtained. A test piece was produced from this sheet.

(Reference Example 3)
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG). A composition (H / NCO ratio is 0.95) comprising the urethane prepolymer (NCO% 5.51%, preheating temperature 66 ° C.) thus obtained and 3,5-dimethylthiotoluenediamine (ETHACURE300) was obtained. Then, it is poured into a preheated mold, heated to 127 ° C., and precured at 127 ° C. for 0.5 hours.
The precured composition is then postcured at 127 ° C. for 16 hours. As a result, a cured polyurethane sheet having a “JIS A hardness” of 96.2 degrees is obtained. A test piece was produced from this sheet.

(Reference Examples 4 to 6)
From the urethane prepolymer and the curing agent shown in FIG. 7, a test piece was produced with a polyurethane sheet in the same manner as in Reference Examples 1 to 3 under the molding conditions shown in FIG.
In addition, the compounding quantity of the hardening | curing agent in FIG. 7 is a weight part number of the hardening | curing agent with respect to 100 weight part when a urethane prepolymer is 100 weight part.

  About the obtained test piece, "JIS A hardness", tensile strength (JIS K6251: dumbbell No. 3, tensile speed 500 mm / min) and tear strength (JIS K6252, tearing speed 500 mm / min, with angle notch) Compressive strain (JIS K6262) was measured, and each physical property was evaluated by a wear test and a demacha-type bending test. The obtained physical properties are shown in FIG.

In the abrasion test, the test piece is attached to the lower part of the press board. And it was rotated, pressing the rotary roll provided with a friction element on the outer periphery (surface to be measured) thereunder.
At this time, the pressure by the rotating roll is 9.6 kg / cm, and the rotating roll is rotated for 20 minutes at a rotation speed of 100 m / min. After the rotation, the thickness reduction amount (that is, the wear amount) of the belt sample was measured.
It can be seen that the wear resistance of the resin according to the first embodiment is improved by 30% or more compared to the belt of the prior art.

  Next, with respect to the second embodiment, in order to evaluate the physical properties of the polyurethane that forms the reinforcing resin layers 14 and 14a to 14h of the belt, in the case of producing a polyurethane test piece, Reference Example 11 in FIGS. This will be described with reference to.

(Reference Example 11)
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG). A curing agent mixture is obtained with 97 mol% 1,4-butanediol (1,4BD) and 3 mol% 3,5-diethyltoluenediamine (ETHACURE 100).
Then, a urethane prepolymer (NCO% is 5.51%, the viscosity at 55 ° C. is 1,800 cps, the preheating temperature is 66 ° C.) and the curing agent mixture are mixed. In this case, the H / NCO equivalent ratio is 0.95. The polyurethane resin mixture is simply indicated as “PPDI / PTMG / 1,4BD + ETHACURE100: H / NCO = 0.95”.
The mixture thus obtained is poured into a mold preheated to 127 ° C., the mold is heated to 127 ° C., and precured at 127 ° C. for 30 minutes. Thereafter, the upper mold is removed from the mold, and the mixture is further post-cured at 127 ° C. for 16 hours. As a result, a cured polyurethane sheet having a “JIS A hardness” of 98.1 degrees is obtained. A test piece (thickness: 1.5 mm) was produced from this sheet.

(Reference Example 12)
A urethane prepolymer is obtained by reacting p-phenylene diisocyanate (PPDI) with polytetramethylene glycol (PTMG). A curing agent mixture is obtained with 95 mol% 1,4-butanediol (1,4BD) and 5 mol% 3,5-dimethylthiotoluenediamine (ETHACURE300).
Then, a urethane prepolymer (NCO% is 5.51%, the viscosity at 55 ° C. is 1,800 cps, the preheating temperature is 66 ° C.) and the curing agent mixture are mixed. In this case, the H / NCO equivalent ratio is 0.95.
The mixture thus obtained is poured into a mold preheated to 127 ° C., the mold is heated to 127 ° C., and precured at 127 ° C. for 30 minutes. Thereafter, the upper mold is removed from the mold, and the mixture is further post-cured at 127 ° C. for 16 hours. As a result, a cured polyurethane sheet having a “JIS A hardness” of 98.2 degrees is obtained. A test piece (thickness: 1.5 mm) was produced from this sheet.

(Reference Example 13 (for comparison))
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG).
A composition is obtained from this urethane prepolymer (NCO% is 5.51%, viscosity at 55 ° C. is 1,800 cps, preheating temperature is 66 ° C.) and 1,4-butanediol (1,4BD). . In this case, the H / NCO equivalent ratio is 0.95.
The composition thus obtained is poured into a mold preheated to 127 ° C., the mold is heated to 127 ° C., and precured at 127 ° C. for 30 minutes. Thereafter, the upper mold is removed from the mold, and the composition is further post-cured at 127 ° C. for 16 hours. Thereby, a cured polyurethane sheet having a “JIS A hardness” of 98.1 degrees is obtained. A test piece (thickness 1.5 mm) was prepared from this sheet.

(Reference Example 14)
A urethane prepolymer is obtained by reacting p-phenylene-diisocyanate (PPDI) with polytetramethylene glycol (PTMG). A curing agent mixture is obtained with 90 mol% 1,4-butanediol (1,4BD) and 10 mol% 3,5-dimethylthiotoluenediamine (ETHACURE300).
Then, the urethane prepolymer (NCO% is 3.03%, the viscosity at 70 ° C. is 7,000 cps, the dissolution temperature is 100 ° C.) and the curing agent mixture are mixed. In this case, the H / NCO equivalent ratio is 0.95.
The mixture thus obtained is poured into a mold preheated to 127 ° C., the mold is heated to 127 ° C., and precured at 127 ° C. for 60 minutes. The mixture is then post-cured at 127 ° C. for 16 hours. Thus, a cured polyurethane sheet having a “JIS A hardness” of 95.6 degrees is obtained. A test piece (thickness 1.5 mm) was prepared from this sheet.

(Reference Example 15 (for comparison))
A urethane prepolymer is obtained by reacting a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate (TDI) with polytetramethylene glycol (PTMG).
A composition is obtained from this urethane prepolymer (NCO% is 6.02%, viscosity at 80 ° C. is 400 cps, preheating temperature is 66 ° C.) and 3,5-dimethylthiotoluenediamine (ETHACURE300). In this case, the H / NCO equivalent ratio is 0.95.
The composition is poured into a preheated mold, heated to 100 ° C. and precured at 100 ° C. for 30 minutes. The composition is then post cured at 100 ° C. for 16 hours. As a result, a cured polyurethane sheet having a “JIS A hardness” of 96.2 degrees is obtained. A test piece (thickness 1.5 mm) was produced from this sheet.

(Reference Examples 16 to 18 (for comparison))
A test piece (thickness 1.5 mm) was made of a polyurethane sheet from the urethane prepolymer and the curing agent shown in FIGS. 8 and 9 in the same manner as in Reference Example 11 under the molding conditions shown in FIGS.
In addition, the compounding quantity of the hardening | curing agent in FIG. 8, FIG. 9 is a weight part number of the hardening | curing agent with respect to 100 weight part when a urethane prepolymer is 100 weight part.

  About the obtained test piece, “JIS A hardness”, tensile strength (JIS K6251: dumbbell No. 3, tensile speed 500 mm / min), tear strength (JIS K6252, tear speed 500 mm / min, with angle notch) In addition, each physical property was evaluated by a wear test and a demacha-type bending test. The obtained physical properties are shown in FIGS.

In the abrasion test, the test piece is attached to the lower part of the press board. And it was rotated, pressing the rotary roll provided with a friction element on the outer periphery (surface to be measured) thereunder.
At this time, the pressure by the rotating roll is 9.6 kg / cm, and the rotating roll is rotated for 20 minutes at a rotation speed of 100 m / min. After the rotation, the thickness reduction amount (that is, the wear amount) of the belt sample was measured.

8 and 9, the test pieces of Reference Example 11, Reference Example 12 and Reference Example 13 have an abrasion amount of 0.1 mm or less and are much less wearable than the test pieces in the comparative example. I understand.
When the bending resistance is compared on the assumption that the amount of wear is small as described above, both the wear resistance and the bending resistance are superior in Reference Example 11 and Reference Example 12 compared to the conventional technology product (Reference Example 15). It was confirmed that a resin layer for reinforcing a belt having mechanical properties was obtained.

Next, an experiment performed using the experimental apparatus 110 will be described.
When the crack resistance is measured using the experimental apparatus 110, the belt sample S is cut in the lateral direction (direction perpendicular to the running direction of the belt and perpendicular to the groove 16). The both ends of are fixed with clamp hands 52 and 52.
The sample S is sandwiched between the rotating roll 53 and the press shoe 54, and the outer peripheral surface of the sample S is in contact with the rotating roll 53. The press shoe 54 is moved in the direction of the rotary roll 53 as indicated by an arrow G to apply a pressing pressure. As a result, the sample S is pressurized at a pressure of 36 kg / cm ² .
Both ends of the sample S are clamped by clamp hands 52 and 52, respectively. In this state, the clamp hands 52, 52 reciprocate in the left-right direction as shown by an arrow B in conjunction with each other. The tension applied to the sample S is 3 kg / cm, and the reciprocating speed is 40 cm / sec.
During the reciprocating motion of the sample S, the length of the sample S is adjusted so that the sample S contacts the rotating roll 53.

Example 1
Belt 1 (Fig. 4A)
1. Base fabric (base layer 12):
As the base fabric, a fabric woven with a warp double weave structure is used. The warp and weft of this fabric are nylon monofilament twisted yarns. The warp is structured so as to be in the belt running direction (MD direction). This base fabric is an endless fabric.

2. Process:
(1) A release agent is applied to the surface of an appropriately rotatable mandrel. Next, a composition prepared by mixing a urethane prepolymer obtained by reacting tolylene diisocyanate (TDI) and polytetramethylene glycol (PTMG) and a curing agent (1,4-butanediol) while rotating the mandrel. Get things.
This composition is laminated while rotating the mandrel using a coater so that the thickness becomes 1.0 mm. The inner peripheral layer 11 is formed by thermosetting the resin with a heating device attached to the mandrel.
(2) An endless base fabric is placed on the inner peripheral layer 11 to form the base layer 12 so that the wefts of the base fabric are arranged along the axial direction of the mandrel.
(3) While rotating the mandrel, the composition is laminated on the base fabric (base layer 12) using a coater bar until the base fabric is embedded with the composition. Lamination is continued, and lamination is performed using a coater bar so that the total thickness of the base fabric and the resin layer on the base fabric is 2.0 mm. Next, the resin is thermally cured by a heating device to form the inner portion of the outer peripheral layer 13.

(4) Further, a resin is laminated on the inner part layer of the outer peripheral layer 13 by spiral coating to form an outer part layer of the outer peripheral layer 13. The outer peripheral layer 13 is formed in the belt center region E and belt predetermined regions E1 and E2 on both sides thereof.
Here, the urethane prepolymer obtained by reacting p-phenylene-diisocyanate (PPDI) and polytetramethylene glycol (PTMG) and a curing agent (1,4-butanediol) are provided in the belt predetermined regions E1 and E2. The composition mixed with is coated.
The belt center region E is coated with a composition using the tolylene diisocyanate (TDI). The composition is coated until the thickness of each of the belt predetermined areas E1, E2 and the belt central area E is 1 mm.
Thereafter, the resin is heat-cured with a heating device to form the outer peripheral layer 13 and the reinforcing resin layer 14. The outer peripheral layer 13 and the inner peripheral layer 11 are formed of the same material resin.
(5) The surfaces of the outer peripheral layer 13 and the reinforcing resin layer 14 are polished to a total thickness of 3.9 mm. Next, a large number of drainage grooves 16 are formed in the MD direction in the belt central region E with a rotary blade, whereby the belt 1 of Example 1 is obtained. The groove 16 has a groove width of 0.8 mm, a groove depth of 1.0 mm, and a groove interval of 3.3 mm.

(Example 2)
Belt 1c (FIG. 5C)
1. Base fabric (base layer 12): The same base fabric as in Example 1 is used.
2. Process:
(1) In the same manner as in the first embodiment, the inner peripheral layer 11 is formed of the same resin material as in the first embodiment.
(2) In the same manner as in Example 1, an endless base fabric is placed on the inner peripheral layer 11 to form the base layer 12.
(3) While rotating the mandrel, the same resin as in Example 1 is laminated on the base fabric (base layer 12) by spiral coating. In this case, the belt predetermined regions E1 and E2 are coated with a composition using the p-phenylene diisocyanate (PPDI).
The belt center region E is coated with a composition using the tolylene diisocyanate (TDI). The composition is coated until the total thickness of the base fabric and the resin layer on the base fabric is 3.0 mm.
Thereafter, the resin is heat-cured with a heating device to form the outer peripheral layer 13 and the reinforcing resin layer 14c.
(4) In the same manner as in Example 1, the surfaces of the outer peripheral layer 13 and the reinforcing resin layer 14c are polished to a total thickness of 3.9 mm. Then, a large number of grooves 16 are formed in the MD direction in the belt central region E with a rotary blade, and the belt 1c of Example 2 is obtained.

(Example 3)
Belt 1e (FIG. 5E)
1. Base fabric (base layer 12): The same base fabric as in Example 1 is used.
2. Process:
(1) While rotating the mandrel, the predetermined region E1, E2 of the belt is coated with the composition using the p-phenylene-diisocyanate (PPDI) by spiral coating on the mandrel.
The belt center region E is coated with a composition using the tolylene diisocyanate (TDI). In these coatings, the spiral coating is performed so that the resin layer thickness in the belt predetermined region and the belt central region is 1.0 mm. Thereafter, the resin is heat-cured with a heating device to form the inner peripheral layer 11 and the reinforcing resin layer 14e.
(2) The same endless base fabric as in Example 1 is placed on the inner peripheral layer 11 and the reinforcing resin layer 14e to form the base layer 12.

(3) While rotating the mandrel, a resin is laminated on the base fabric by spiral coating. In this case, the belt predetermined regions E1 and E2 are coated with a composition using the p-phenylene diisocyanate (PPDI).
The belt center region E is coated with a composition using the tolylene diisocyanate (TDI). The composition is coated until the total thickness of the base fabric and the resin layer on the base fabric is 3.0 mm. Thereafter, the resin is thermally cured with a heating device to form the outer peripheral layer 13 and the reinforcing resin layer 14e.
(4) In the same manner as in Example 1, the surfaces of the outer peripheral layer 13 and the reinforcing resin layer 14e are polished to a total thickness of 3.9 mm. Next, a large number of grooves 16 are formed in the MD direction in the belt central region E with a rotary blade, whereby the belt 1e of Example 3 is obtained.

Example 4
It is a modification of the belt 1c (FIG. 5C) of Example 2.
In the belt predetermined regions E1 and E2 of the belt 1c of the second embodiment, a number of grooves 16 are formed in the MD direction to obtain the belt of the fourth embodiment.

(Comparative Example 1)
Belt 100 (FIG. 6)
1. Base fabric (base layer 12): The same base fabric as in Example 1 is used.
2. Process:
(1) In the same manner as in Example 1, the inner peripheral layer 11 is formed by coating the composition using the tolylene diisocyanate (TDI).
(2) In the same manner as in Example 1, an endless base fabric is placed on the inner peripheral layer 11 to form the base layer 12.
(3) In the same manner as in Example 1, lamination is performed until the base fabric is embedded with the composition. Lamination is continued, and lamination is performed while rotating the mandrel using a coater so that the total thickness of the base fabric and the resin layer on the base fabric is 3.0 mm. Next, the outer peripheral layer 13 is formed by thermosetting the resin with a heating device.
(4) In the same manner as in Example 1, the surface of the outer peripheral layer 13 is polished to a total thickness of 4.9 mm. And the belt 100 of the comparative example 1 is obtained by forming many drainage grooves in the MD direction in the belt central region E with the rotary blade.

(Comparative Example 2)
In the belt predetermined regions E1 and E2 of the belt of the comparative example 1, a number of drainage grooves are formed in the MD direction to obtain the belt of the comparative example 2.

(performance test)
(1) Bending stress test Based on the plastic bending property test method of JIS K7171, each belt obtained in Examples 1 to 4 and Comparative Examples 1 and 2 is cut to the size of a standard test piece, and the maximum bending stress is measured. did.
The evaluation of the bending stress was made based on the value of the maximum bending stress in the belt predetermined areas E1 and E2 when the maximum bending stress in the central area E of the belt was 100.
(2) Crack Test Using the experimental apparatus 110 shown in FIG. 10, the belt sample S repeated the reciprocating motion, and the number of reciprocations (the number of presses) until a crack occurred in the belt predetermined areas E1 and E2 of the sample S was measured.

As shown in FIG. 11, in the bending stress test, the maximum bending stress in the belt predetermined region E1 + E2 is the same as that in the belt of Comparative Example 1 and about 30% smaller in the belt of Comparative Example 2 than the belt center region E. It was.
On the other hand, in each belt according to Examples 1 to 4, the maximum bending stress of the belt predetermined region E1 + E2 is about 30% to 70% larger than the belt center region E. Thereby, it can be seen that the compression elastic modulus in the belt predetermined region E1 + E2 is higher than that in the belt central region E, and bending deformation and residual strain are reduced.
Regarding the crack test, the number of presses until a crack occurred in the groove 16 formed in the belt predetermined region E1 + E2 of the sample S was measured. As a result, in the belt of Comparative Example 1, cracks occurred in the number of presses of 100,000 to 150,000 times, and in the belt of Comparative Example 2, cracks occurred in the number of presses of 50,000 to 100,000 times. .
On the other hand, in each belt according to Examples 1 to 4, no crack was generated even when the number of presses was 300,000 times or more.

The belts 1, 1 a to 1 h of the present invention having the above-described configuration have a higher compression elastic modulus in a predetermined region that forms part of the belt corresponding to the shoe edge portion 8 as compared with the conventional belt. Yes. Thereby, since bending deformation and residual strain are reduced, the occurrence of cracks in this predetermined region can be suppressed.
In the present invention, the reinforcing resin layers 14 and 14a to 14h are used only in predetermined regions of the belts 1 and 1a to 1h. Therefore, the time for coating the composition using the p-phenylene diisocyanate (PPDI) and then thermally curing the resin with a heating device is short. Therefore, it is difficult to be influenced by the surrounding environment (particularly temperature and humidity) of the process until reaching the curing.
The belts 1 and 1a to 1h can improve the durability of the entire belt by improving the crack resistance, the bending fatigue resistance and the wear resistance in the predetermined region. For example, the durability of the belts 1, 1 a to 1 h can withstand 1.5 times or more use compared to the durability of conventional belts.

As mentioned above, although various embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation, addition, etc. are possible in the range of the summary of this invention.
In the drawings, the same reference numerals denote the same or corresponding parts.

  The shoe press belt of the present invention is applicable to a closed type papermaking shoe press.

1 to 5H are views showing an embodiment of the present invention, and FIG. 1 is a perspective view showing a schematic configuration of a shoe press mechanism. It is sectional drawing of schematic structure of a shoe press mechanism. FIG. 3 is a cross-sectional view in the weft direction of a press portion in the shoe press mechanism of FIG. 2. It is sectional drawing of the belt for shoe presses. It is the IV section expanded sectional view in FIG. 4A. FIG. 4B is an enlarged cross-sectional view corresponding to FIG. 4B and shows a modification. It is sectional drawing of the belt for shoe press concerning the modification of this embodiment. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the belt for shoe presses concerning another modification. It is sectional drawing of the conventional belt for shoe presses. It is a table | surface which shows the experimental data of 1st Embodiment. It is a table | surface which shows the experimental data of 2nd Embodiment. It is a table | surface which shows the experimental data of 2nd Embodiment. It is the schematic of the experimental apparatus for investigating crack resistance. It is a table | surface which shows an experimental result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shoe press belt 1a-1h Shoe press belt 2 Press roll 3 Shoe 4 Shoe press mechanism 8 Shoe edge part 11 Inner peripheral layer 12 Base layer 13 Outer peripheral layer 14 Reinforcement resin layer 14a-14h Reinforcement resin layer 18 Intermediate layer 30 Concavity E Belt center area E1 Shoe edge contact area (predetermined area)
E2 Belt end area E1 + E2 Shoe edge contact area and belt end area (predetermined area)

Claims (9)

It is arranged between the press roll of the shoe press mechanism and the shoe below or above it and rotates,
A shoe press belt comprising a resin inner peripheral layer in contact with the shoe, a base layer provided on the outer periphery of the inner peripheral layer, and a resin outer peripheral layer formed on the outer periphery of the base layer. There,
The shoe press belt is located in the width direction in a belt center region that is in contact with the shoe, on the outer side in the width direction from the belt center region, and corresponding to the shoe edge portions on both sides in the width direction of the shoe. It is divided into a pair of predetermined areas that form part of the shoe press belt,
The shoe press belt has a pair of reinforcing resin layers made of a polyurethane layer having a component different from the polyurethane layer in the belt central region,
The pair of reinforcing resin layers are arranged around the pair of predetermined regions in the belt running direction,
The polyurethane layer constituting the reinforcing resin layer contains a polyurethane obtained by curing a composition in which a urethane prepolymer (A) and a curing agent (B) are mixed,
The urethane prepolymer (A) is
It is a urethane prepolymer obtained by reacting an isocyanate compound (a) containing 55 to 100 mol% of a p-phenylene-diisocyanate compound with polytetramethylene glycol (b) and having an isocyanate group at the terminal,
The curing agent (B) is
A shoe press belt, wherein the belt is selected from the group consisting of 1,4-butanediol, hydroquinone bis-β hydroxyl ethyl ether, 3,5-diethyltoluenediamine, and 3,5-dimethylthiotoluenediamine. It is arranged between the press roll of the shoe press mechanism and the shoe below or above it and rotates,
A shoe press belt comprising a resin inner peripheral layer in contact with the shoe, a base layer provided on the outer periphery of the inner peripheral layer, and a resin outer peripheral layer formed on the outer periphery of the base layer. There,
The shoe press belt is located in the width direction in a belt center region that is in contact with the shoe, on the outer side in the width direction from the belt center region, and corresponding to the shoe edge portions on both sides in the width direction of the shoe. It is divided into a pair of predetermined areas that form part of the shoe press belt,
The shoe press belt has a pair of reinforcing resin layers made of a polyurethane layer having a component different from the polyurethane layer in the belt central region,
The pair of reinforcing resin layers are arranged around the pair of predetermined regions in the belt running direction,
The polyurethane layer constituting the reinforcing resin layer is a polyurethane obtained by curing a composition in which a urethane prepolymer (A) and a curing agent (B) having an active hydrogen group (H) are mixed. Contains
The urethane prepolymer (A) is obtained by reacting an isocyanate compound (a) with polytetramethylene glycol (b), and is a urethane prepolymer having an isocyanate group at the terminal,
The isocyanate compound (a) contains 55 to 100 mol% of an isocyanate compound selected from a p-phenylene-diisocyanate compound and 4,4′-methylenebis (phenylisocyanate),
The curing agent (B) contains 85 to 99.9 mol% of 1,4-butanediol and 15 to 0.1 mol% of the aromatic polyamine having the active hydrogen group (H). A belt for shoe presses characterized by being. The aromatic polyamine having the active hydrogen group (H) is:
3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, 3,5-dimethylthiotoluene-2,4-diamine, 3,5-dimethylthiotoluene-2 6-diamine, 4,4′-bis (2-chloroaniline), 4,4′-bis (sec-butylamino) -diphenylmethane, N, N′-dialkyldiaminodiphenylmethane, 4,4′-methylenedianiline, 4,4'-methylene-bis (2,3-dichloroaniline), 4,4'-methylene-bis (2-chloroaniline), 4,4'-methylene-bis (2-ethyl-6-methylaniline) The aromatic polyamine is one or a mixture of two or more selected from the group consisting of trimethylene-bis (4-aminobenzoate) and phenylenediamine. Shoe press belt.   4. The shoe press belt according to claim 1, wherein the reinforcing resin layer is fixed to and integrated with at least the outer peripheral layer and is exposed to the outer peripheral surface side.   The reinforcing resin layer is integrally fixed only to the outer peripheral layer, the reinforcing resin layer is integrally fixed to the base layer from the outer peripheral layer, and the base layer passes from the outer peripheral layer. 5. The shoe press belt according to claim 4, wherein the shoe press belt has one configuration selected from the group consisting of a case where the inner peripheral layer is integrally fixed to the inner peripheral layer. The predetermined region that forms a part of the shoe press belt includes a shoe edge contact portion region that is located on the outer side in the width direction from the belt central region and contacts the shoe edge portion, and the shoe edge contact portion region. A region including a belt end region located outside in the width direction and including a weft direction end perpendicular to the belt running direction,
6. The shoe press belt according to claim 1, wherein the reinforcing resin layer is disposed in both the shoe edge contact region and the belt end region. . The predetermined region that forms a part of the shoe press belt is a shoe edge contact portion region that is located on the outer side in the width direction from the belt center region and contacts the shoe edge portion,
6. The shoe press belt according to claim 1, wherein the reinforcing resin layer is disposed only in the shoe edge contact portion region.   The shoe press belt according to any one of claims 1 to 7, wherein a concave portion extending in the belt running direction is formed on a surface of the reinforcing resin layer. The shoe press belt further includes a resin intermediate layer in which the base layer is embedded,
The inner peripheral layer and the outer peripheral layer are respectively laminated on the inner periphery and the outer periphery of the intermediate layer, and the entire resin layer has at least a three-layer structure. A shoe press belt according to claim 1.

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