JP3497636B2 - Spiral canvas for papermaking - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a spiral canvas for papermaking used in a dry part of a papermaking machine.

[0002]

2. Description of the Related Art The role of a canvas in a dry part of a paper machine is to hold wet paper received from a press part (pressing part) and press it onto a drying cylinder while transporting it to promote efficient drying and to obtain a predetermined moisture content and quality. The purpose is to finish the paper with the paper and send it to the calendar and reel. In order to play such a role, this kind of canvas is generally required to have the following characteristics. That is,
Excellent durability (tensile strength), heat resistance, chemical resistance, and wear resistance. Good dimensional stability in the longitudinal and width directions. The surface should be smooth or flexible to improve the quality of the paper. Good breathability for better drying. Good running stability, etc.

As a canvas used in the dry part of a paper machine as described above, a plurality of spiral coils are arranged in parallel in the longitudinal direction of the canvas, and a core wire is formed in a common hole formed by mutually meshing adjacent turn portions. There is a spiral canvas with the structure inserted. The spiral canvas is used in the dry part of a paper machine because it has structurally high tensile strength, high air permeability, good surface smoothness, and excellent bendability, and does not require a joint part. .

As a spiral canvas, for example, a structure described in West German Patent Publication No. 2419751 is known. In the spiral canvas described in the publication, a right-handed spiral coil and a left-handed spiral coil are alternately combined by utilizing the repulsive force of the side surface of the spiral coil, and a space portion (common hole) formed by the combination
The core wire is inserted into the endless shape and is connected endlessly with a required length in the longitudinal direction of the canvas. However, the spiral canvas having this structure has insufficient dimensional stability when used in a paper machine application.

Therefore, in order to improve the dimensional stability, for example, a link belt described in JP-B-4-5797 has been proposed. The link belt described in the publication has the following structure.

As shown in FIG. 11, a plurality of spiral coils 11 are arranged in a finger-like shape, and hinge wires 12 are respectively provided in finger-like turn portions 11a of adjacent coils 11.
(Hinge wire 12 is the common hole 1 shown in FIG.
Insert 1b. ), The hinge belt 13 is first formed by connecting the adjacent coils 11 to each other.

The hinge belt 13 is then tensioned and heat treated for a time sufficient to cause the coil 11 (and / or) hinge wire 12 material to deform and sufficient to cause this deformation. As a result, as shown in FIG. 12, the coil 11 is heat-fixed in a state of being deformed from the initial constant cross-sectional shape, and the coil 11 is deformed by this deformation.
However, in the range where the coil 11 and the hinge wire 12 are close to each other, the hinge wire 12 has a substantially oval cross-sectional shape that is long in the axial direction, and the oval cross-sectional shape portion grips the hinge wire 12 and closely engages it. The dimensional stability is imparted to the hinge belt 13.

[0008]

The link belt described in JP-B-4-5797 can be said to be excellent in terms of dimensional stability, but when used in a dry part of a paper machine, it has flexibility and durability. There are the following worries about the point.

First, considering the bendability in the longitudinal direction (L direction in FIGS. 11 and 12) at the time of bending with a dryer roll or the like, the link belt 13 (spiral canvas) is originally the hinge wire 12 (core wire). Although it rotates and bends about the center as a fulcrum, in the structure in which the turn portion 11a of the coil 11 grips and tightly engages the hinge wire 12, the sliding friction resistance of the contact portion between the turn portion 11a and the hinge wire 12 is large, and moreover, Turn part 11a
Has no appropriate elasticity, the rotation of the turn portion 11a necessary for bending cannot be obtained, and there is a concern that the link belt 13 will not be smoothly bent. Also, the turn portion 11a
When the rotation of the coil 11 is not obtained, the link belt 13 tries to take a bending posture due to the deformation of the material of the coil 11, so that an excessive repetitive stress acts particularly on the turn portion 11a of the coil 11, which deteriorates the durability. It is easy to become a factor.

Next, in the width direction (W direction in FIG. 12b)
Considering the flexibility of the coil, the turn portion 11 of the coil 11
In the structure in which a grips the hinge wire 12 and is closely engaged,
Since the turn portions 11a do not have appropriate elasticity, there is a concern that the adjacent turn portions 11a strongly interfere with each other during bending and the link belt 13 does not bend smoothly. In this type of canvas, the ears on both side edges of the canvas do not have wet paper intervening, so the center main body where the wet paper intervenes and the other ears do not bend (when traveling on the surface of the drying cylinder). The turning radii differ by the thickness of the wet paper. Therefore, if the flexibility in the width direction is not good, the difference in the radii of rotation cannot be absorbed smoothly, and the ear portion sags. Further, since the ear without the wet paper is in direct contact with the surface of the drying cylinder and is directly exposed to high-temperature steam, it is more susceptible to heat than the central body. Particularly, in the case of a spiral canvas, unlike a normal woven canvas, since there are no continuous yarns in the longitudinal direction, it is very susceptible to this effect, and the phenomenon that the ears sag down tends to occur.

An object of the present invention is to provide a spiral canvas for papermaking, which has good dimensional stability and is excellent in flexibility and durability.

[0012]

In order to solve the above problems, according to the present invention, a plurality of spiral coils made of synthetic resin are arranged in parallel in the longitudinal direction of the canvas, and the adjacent turn portions are meshed with each other. In the configuration in which the core wire is inserted through the common hole and the core wire and the turn portion of the spiral coil are deformed and adapted by heat setting, the cross section shape of the core wire is hexagonal, and the core wire and the turn portion of the spiral coil are compatible. In the area, the two are partially in contact with each other.

Here, "Heat Settin
g) ”is generally a processing method in which fibers are heat treated to stabilize their dimensions or fix their shape.
Processing conditions vary depending on the application, use conditions, materials, etc., but in the case of a synthetic resin canvas, it is usually at a predetermined temperature under a predetermined tension (in the case of a thermoplastic resin, it is usually below the adhesion temperature of the resin material, In many cases, the heat treatment is performed at a temperature equal to or higher than the glass transition point for a predetermined time. In the present invention,
The heat setting is performed after assembling a plurality of spiral coils and a core wire into an endless shape having a required length, and the heat setting heat-fixes the core wire and the turn portion of the spiral coil in a compatible state. The cross-sectional shape of the core wire is a hexagonal shape, and in a region where the core wire and the turn portion of the spiral coil fit together, the two parts are partially in contact with each other, so that the canvas has good dimensional stability.

"Partially contact" means that only a part of the region is in contact, and that the other region is not in contact, that is, in the other region, between the core wire and the turn portion of the spiral coil. 2 to 4. That is, there is a gap in the core wire, as shown in FIGS. 2 to 4, only the corners of the core wire are in contact with the turns of the spiral coil (claim 2), and FIGS. As shown in (3), a state in which the corners and sides of the core wire are in contact with the turns of the spiral coil (claim 3) is included. The "partial contact" here occurs when at least one of the core wire and the turn portion of the spiral coil is deformed and heat-fixed by heat setting to such a state.

The above-mentioned "partially contacting" structure has an important role as described below, in particular, for ensuring good flexibility and durability of the canvas. First, the conventional configuration (Japanese Patent Publication No. 4-5
No. 797), the contact area between the core wire and the turn portion of the spiral coil becomes smaller, and the sliding friction resistance at the contact portion decreases, so that smooth rotation of the turn portion during bending is ensured. Also, due to the presence of the gap,
Since the turn portion of the spiral coil is imparted with appropriate elasticity, the bending in the width direction is also smooth, and the material is less likely to undergo an unreasonable material deformation that causes a decrease in durability.

The reason why the cross-sectional shape of the core wire is "hexagonal" is as follows. As mentioned above, the present invention provides
The purpose is to ensure the dimensional stability of the canvas and at the same time improve the flexibility and durability.As a means to achieve that purpose, the core wire and the turn part of the spiral coil are partially contacted by heat setting. The configuration adopted is Therefore, the cross-sectional shape of the core wire may be any shape as long as such a partial contact state can be obtained, and generally, it may be a "polygonal shape". However, it is difficult to manufacture a core wire whose cross-sectional shape is asymmetric, and it is not practical. Therefore, we made prototypes of various core wires whose cross-sectional shapes are square, hexagonal, octagonal, and dodecagonal.
A study was conducted. As a result of investigation, it was found that the regular quadrangular shape did not provide sufficient dimensional stability, and the regular octagonal shape and the regular dodecagonal shape did not provide good bendability. on the other hand,
With the regular hexagonal shape, good results were obtained in terms of dimensional stability and flexibility. This is because if the number of corners of the core wire (cross section) is too small, the contact area with the turn part becomes too small, and therefore good dimensional stability cannot be obtained. Conversely, if the number of corners is too large,
It is considered that this is because the contact area with the turn portion becomes excessively large, and at the same time, the turn portion is not provided with appropriate elasticity, and therefore good bendability cannot be obtained. Therefore, there is an optimum number of angles that can balance the demands of dimensional stability with the demands of flexibility and durability.
It was confirmed experimentally that

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. As shown in FIG. 1, a plurality of spiral coils 1 in which a monofilament made of synthetic resin is spirally wound are arranged in parallel in the canvas longitudinal direction L, and a common hole formed by mutually engaging adjacent turn portions 1a with each other. An endless spiral canvas 3 is first formed by inserting a core wire 2 made of a synthetic resin monofilament into and connecting adjacent spiral coils 1 to each other. The cross-sectional shape of the core wire 2 is a regular hexagonal shape, and in this embodiment, the core wire 2 is inserted into the common hole so that the corner portion 2a thereof is located in the canvas thickness direction H. The initial shape (shape before heat setting) of the spiral coil 1 may be an elliptical shape as shown in FIG. 1A, a circular shape, a flat cross-sectional shape, or the like.

Next, the spiral canvas 3 as described above
In order to impart dimensional stability to, heat setting is performed at a predetermined temperature under a predetermined tension. As a result, as shown in FIGS. 2 to 4, the core wire 2 and the turn portion 1a of the spiral coil 1 are deformed and adapted, and the corner portion 2a of the core wire 2 is turned.
By contacting with a, the spiral canvas 3 is provided with good dimensional stability. By selecting materials having appropriate physical properties for the constituent materials of the spiral coil 1 and the core wire 2, one or both of the spiral coil 1 and the core wire 2 can be deformed, and dimensional stability can be obtained by various different modes. Can be given.

In the embodiment shown in FIG. 2, the corner portion 2a of the core wire 2 is compressed by the turn portion 1a of the spiral coil 1,
It is in contact with the turn portion 1a in a rounded state. A slight gap S exists between the side portion 2b of the core wire 2 and the turn portion 1a. In addition, FIG. 3 {A-A cross section of FIG. 2A}
As shown in, the deformed turn portions 1a come into close contact with each other,
Good dimensional stability is provided by connecting adjacent spiral coils 1 to each other.

By contacting only the corner portion 2a of the core wire 2 with the turn portion 1a of the spiral coil 1, the contact area between the core wire 2 and the turn portion 1a is reduced, and the sliding friction resistance of the contact portion is reduced. A smooth rotation of the turn portion 1a is ensured when the direction is bent. Particularly, in this embodiment, since the corner portions 2a of the core wire 2 are in contact with each other in a rounded state, the turn portion 1a can be rotated more smoothly. Therefore, the spiral canvas 3 has very good flexibility in the longitudinal direction. Further, since there is a gap S between the side portion 2b of the core wire 2 and the turn portion 1a, and the turn portion 1a has an appropriate elasticity, the flexibility in the width direction is also very good.

In FIG. 1A, the spiral coil 1
Is D1 = 0.7 mm polyester monofilament (cross-sectional shape: circular shape), and core wire 2 is t1 = 0.9 mm
Polyester monofilament (cross-sectional shape: regular hexagonal shape), tension = 8 kgf / cm, temperature = 190 ° C
Was heat-set, and the shape change of the corner 2a of the core wire 2 was observed. As a result of the observation, it was found that the corner portion 2a of the core wire 2 had a relatively large arcuate roundness and was heat-fixed in a state of being in close contact with the turn portion 1a of the spiral coil 1. From this, it was confirmed that the cross-sectional shape of the core wire 2 was best hexagonal.

In the embodiment shown in FIG. 4, the corner portion 2a of the core wire 2 slightly contacts the turn portion 1a of the spiral coil 1 and is in contact therewith. Therefore, the dimensional stability is further improved.

In the above-described embodiment, only the corner portion 2a of the core wire 2 is brought into contact with the turn portion 1a of the spiral coil 1. Next, the corner portion 2a and the side portion 2b of the core wire 2 are connected to the spiral coil 1. An embodiment in which the turn portion 1a is brought into contact will be described.

As shown in FIG. 5, a plurality of spiral coils 1 made of spirally wound monofilament made of synthetic resin are arranged in parallel in the canvas longitudinal direction L, and adjacent turn portions 1a are formed by meshing with each other. An endless spiral canvas 3'is first formed by inserting a core wire 2 made of a synthetic resin monofilament into the common hole and connecting adjacent spiral coils 1 to each other. The cross-sectional shape of the core wire 2 is a regular hexagonal shape, and in this embodiment, the core wire 2 is inserted into the common hole so that the side portion 2b thereof is located in the canvas thickness direction H. The initial shape (shape before heat setting) of the spiral coil 1 may be an elliptical shape as shown in FIG. 5A, a circular shape, a flat cross-sectional shape, or the like.

Next, in order to impart dimensional stability to the spiral canvas 3'as described above, heat setting is performed at a predetermined temperature under a predetermined tension. As a result, FIG.
As shown in FIG. 8, the core wire 2 and the turn portion 1a of the spiral coil 1 are deformed and adapted, and the corner portion 2a and the side portion 2b of the core wire 2 are in contact with the turn portion 1a, so that the spiral canvas 3'is good. Dimensional stability is imparted. By selecting materials having appropriate physical properties for the constituent materials of the spiral coil 1 and the core wire 2, one or both of the spiral coil 1 and the core wire 2 can be deformed, and dimensional stability can be obtained by various different modes. Can be given.

In the embodiment shown in FIG. 6, the upper and lower side portions 2b of the core wire 2 are in contact with the turn portion 1a while being compressed by the turn portion 1a of the spiral coil 1. A slight gap S is provided between the side portion 2b on the side of the core wire 2 and the turn portion 1a.
Exists. Further, as shown in FIG. 7 (section B-B in FIG. 6A), the deformed turn portions 1a are in close contact with each other and the adjacent spiral coils 1 are connected to each other, thereby providing good dimensional stability. To be done.

The spiral canvas 3'of this embodiment
The corner portions 2a and the upper and lower side portions 2b of the core wire 2 come into contact with the turn portions 1a of the spiral coil 1, so that the dimensional stability is further improved and the thickness H is smaller than that of the spiral canvas 3 described above. Has the advantage that
Also in this spiral canvas 3 ', since the core wire 2 and the turn portion 1a are partially in contact with each other and a gap S is present between them, the same good flexibility as that of the spiral canvas 3 described above can be obtained. .

In the embodiment shown in FIG. 8, the upper and lower side portions 2b of the core wire 2 are slightly in contact with the turn portion 1a of the spiral coil 1 and are in contact therewith. Therefore, the dimensional stability is further improved.

In the spiral canvas to which the present invention is applied, when it is desired to reduce the air permeability, for example, as shown in FIG. 9, a flat strip 4 (tape-shaped or thread-shaped) is provided in the space 1b of the spiral coil 1. Or the like), or, as shown in FIG. 10, a hexagonal core wire 2'having a flat cross section in the longitudinal direction L may be used. As apparent from the embodiment shown in FIG. 10, in the present invention, the cross-sectional shape of the core wire 2 is not limited to the regular hexagonal shape.

In the above-described embodiment, the heat setting processing conditions may be appropriately determined in consideration of the dry part conditions of the paper machine using the spiral canvas, the constituent materials of the spiral coil 1 and the core wire 2, and the like. Usually, the tension is about 1 to 15 kgf / cm, and the temperature is about 120 to 250 ° C. As for the constituent materials of the spiral coil 1 and the core wire 2, at least one of them may be a thermoplastic synthetic resin. Examples of the thermoplastic synthetic resin include polyester, polyethylene, polyamide, aromatic polyamide, polypropylene, polyphenylene sulfide, and polyether ether ketone. Further, the cross-sectional shape of the spiral coil 1 is not limited to a circular shape, but may be various shapes such as an elliptical shape, a square shape, a flat shape, etc., and the dimensions of the spiral coil 1 and the core wire 2 should be within various ranges. You can Also, spiral coil 1
The shape of the material forming the is not limited to a circular cross-sectional shape, but may be, for example, a flat shape and the dimensions can be set in various ranges.

Needless to say, the spiral canvas described above can be used as a base fabric, and webs can be laminated on one or both sides of the base fabric to form a needle canvas.
Further, the adjacent spiral coils 1 can be favorably connected to each other by combining opposite winding directions (for example, right-handed and left-handed spiral coils 1).

[0032]

EXAMPLE A spiral canvas 3 having the form shown in FIGS. 1 to 3 was manufactured with the following specifications. Spiral coil 1
Was produced by using a polyester monofilament yarn having a circular cross section and a diameter D1 = 0.7 mm. The width (dimension in the L direction in FIG. 1A) of each spiral coil 1 thus produced was 7 mm, and the height (dimension in the H direction in FIG. 1A) was 4 mm. The core wire 2 was manufactured by using a polyester monofilament yarn having a regular hexagonal cross section and t1 = 0.9 mm.

Then, a plurality of spiral coils 1 are arranged in parallel in the longitudinal direction L of the canvas, and the core wire 2 is inserted into a common hole formed by meshing the adjacent turn portions 1a to form an endless shape shown in FIG. A spiral canvas 3 was formed. The density in this case is 16.
4 wires / 2.54 cm, core wire 2 is 4.9 wires / 2.54 cm
Met.

The spiral canvas 3 has a tension of 8 kgf.
/ Cm → 1 kgf / cm, and heat set processing was performed under hot air at 190 ° C. The width of the spiral coil 1 after heat setting is 7.4 mm and the air permeability is 35,000 c.
It was c / min / cm ² and the thickness was 2.9 mm.

As a result, when the corner portion 2a of the core wire 2 is compressed by the turn portion 1a of the spiral coil 1 and comes into contact with the turn portion 1a in a rounded state, good dimensional stability is imparted. At the same time, it was confirmed as a result of the test that it has good flexibility in the longitudinal direction and the width direction.

[0036]

As described above, according to the present invention,
The cross section of the core wire has a hexagonal shape, and the core wire and the turn part of the spiral coil are in partial contact, so good dimensional stability and elasticity even at the bending part of the dryer roll are maintained. It is possible to provide a dryer canvas for papermaking, which has good flexibility and durability that can be smoothly bent.

[Brief description of drawings]

FIG. 1 is a sectional view (FIG. A) and a plan view (FIG. B) showing a state before heat setting according to an embodiment of the present invention.

2 is a cross-sectional view (FIG. A) showing one aspect after heat setting of the embodiment shown in FIG. 1, and an enlarged cross-sectional view (FIG. B) showing a peripheral portion of a core wire.

FIG. 3 is a sectional view taken along the line AA in FIG.

FIG. 4 is an enlarged cross-sectional view showing another aspect of the embodiment shown in FIG. 1 after heat setting.

FIG. 5 is a sectional view (FIG. A) and a plan view (FIG. B) showing a state before heat setting according to another embodiment of the present invention.

6 is a cross-sectional view (FIG. A) showing one aspect after heat setting of the embodiment shown in FIG. 5, and an enlarged cross-sectional view (FIG. B) showing a peripheral portion of a core wire.

FIG. 7 is a sectional view taken along line BB in FIG.

FIG. 8 is an enlarged cross-sectional view showing another aspect of the embodiment shown in FIG. 5 after heat setting.

FIG. 9 is a cross-sectional view showing a state after heat setting according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a state after heat setting according to another embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a state before heat setting of a conventional configuration.

FIG. 12 is a cross-sectional view (FIG. A) showing a state after heat setting of a conventional configuration, and a C-C cross-sectional view (FIG. B) in FIG.

FIG. 13 is a diagram showing a state before inserting a core wire having a conventional configuration.

[Explanation of symbols]

1 spiral coil 1a turn part 2-core wire 2a corner 2b side

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) D21F ^7/ 08-7/10 D21F 1/10-1/12 B65G 15/30-15/58 F16G 3/00-3 / 16

Claims (3)

(57) [Claims] 1. A plurality of spiral coils made of synthetic resin are arranged side by side in the longitudinal direction of a canvas, and a core wire is inserted into a common hole formed by mutually meshing adjacent turn portions, and the core wire and the spiral coil are provided. In the spiral canvas for papermaking in which the turn portion and the turn portion of the spiral coil are deformed and adapted by heat setting, the core wire has a hexagonal cross-sectional shape, and in the area where the core wire and the turn portion of the spiral coil match, both are partially A spiral canvas for papermaking, which is characterized by being in contact with. 2. The spiral canvas for papermaking according to claim 1, wherein only a corner portion of the core wire is in contact with a turn portion of the spiral coil. 3. The spiral canvas for papermaking according to claim 1, wherein the corner portion and the side portion of the core wire are in contact with the turn portion of the spiral coil.