JP3179753B2 - Base fabric for papermaking with flat longitudinal threads - Google Patents

Abstract

A papermakers fabric having a system of flat monofilament machine direction yarns 22,23 (hereinafter MD yarns) interwoven with a system of cross machine direction yarns 21a,21b (hereinafter CMD yarns). The MD yarns 22,23 have an aspect ratio of greater than 3:1. Furthermore the MD yarns are vertically stacked with at least paired upper 22 and lower 23 MD yarns which weave over and under CMD yarns 21a,21b in such a manner that when a lower MD yarn 23 weaves over a CMD yarn 21a an upper MD yarn 22 is weaving (or floating) over the lower MD yarn 23. This ensures that no knuckles are apparent on the upper surface of the fabric. The weave gives rise to a warp-fill in the range of 80-125%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base fabric for papermaking, and more particularly to a base fabric made of flat single fiber yarn.

[0002]

2. Description of the Related Art A papermaking apparatus generally comprises three parts: forming, compressing and drying. Papermaking fabrics have been applied to transport continuous thin paper through papermaking equipment such that thin paper is produced. The required and favorable characteristics of a papermaking fabric differ depending on the features of the device in which each fabric is utilized.

[0003] In response to the development of synthetic yarns, adapted single fiber yarns have been used in the construction of papermaking base fabrics. For example,
U.S. Pat. No. 4,290,209 discloses a base fabric woven with warp of flat monofilaments, and U.S. Pat. No. 4,755,420 discloses a base fabric for papermaking which is flat monofilament. Non-woven structures, such as being formed helically with fiber yarns, are disclosed.

[0004] In the past, various weaves are known which have been adapted to give different results. For example, U.S. Pat.
No. 438,788 discloses a three-layer crossover interwoven with a flat monofilament longitudinal yarn system so that the floating yarn is formed on both the top and bottom surfaces of the backing. There is disclosed a dryer fabric having a defined warp yarn. The floating yarn is supplied to a smooth surface for the base cloth.

[0005] Permeability is an important criterion in the design of papermaking fabrics. In particular, with respect to a base fabric formed to operate at a high speed in a recent drying facility, a relatively low permeability is required for a base fabric for a dryer.

US Pat. No. 4,290,209 discloses an example of the use of flat monofilament warp yarns that are woven together one after the other to reduce the permeability of the base fabric.
However, even when flat warp yarns are continuously woven together, additional means for reducing the permeability of the base fabric, for example, stuffed yarns, are required. As pointed out for that patent, there is a need to avoid the use of fluffy and bulky stuffed yarns and to reduce the permeability with which the backing can trap foreign matter or retained water.

US Pat. No. 4,290,209 and US Pat. No. 4,755,420 describe the warp ratio of the warp in the longitudinal direction (the ratio of the width to the height of the cross section) which defines the structural weave of the base fabric. )
Practical restrictions on are mentioned. The most practical aspect ratio in these patents is 3: 1, but preferably less than 2: 1.

No. 4,621,663, assigned to the assignee of the present invention, shows one attempt to utilize high aspect ratio yarns to define the surface of a paper dryer backing fabric. Have been. As disclosed in that invention, a woven base fabric is provided to support high aspect ratio face yarns. The woven base fabric is made of ordinary spherical yarn and structurally supported and stably provided with respect to the base fabric disclosed in the invention.

US Pat. No. 4,815,499 discloses the use of flat yarns in forming a base fabric. The present invention discloses a hybrid base fabric composed of an upper base fabric and a lower base fabric joined together by binding yarns. In the upper and lower backings, the aspect ratio applied for flat warp yarns is well below 3: 1.

In its use, the papermaking base fabric is formed as an endless belt. The weaving technique is first applied to weaving the base fabric endlessly. However, there are substantial limitations on the overall size of the endless woven base fabric as well as the inherent difficulties of mounting. Further, papermaking equipment is not always designed to allow the attachment of endless base fabrics.

A flat woven base fabric may be supplied having opposing ends that are sewn together during installation of the base fabric in a papermaking facility. One end of the base fabric is usually passed through a bent path defined by a papermaking facility and joined to its opposite end to form a continuous belt.

Conventionally, various suturing techniques are known. A common suturing method is to construct the longitudinal threads on each end of the backing into a series of loops. Next, each of the annular base fabric ends
During the mounting of the base cloth, the shaft needle is inserted so as to be engaged with each other and to fix the ends together.

For example, US Pat. No. 4,026,331
No. 4,438,789; No. 4,469,142
No. 4,846,231; 4,824,525
No. 4,883,096 discloses various pin stitches in which the longitudinal thread is adapted to form an annular end. However, in these inventions, the warp yarns protrude from the end of the base fabric and are woven behind the base fabric adjacent to itself. Thus, the annular yarn inherently has a factor of twist or torsional moment, and
It is not perpendicular to the plane of the base fabric at all. Such a problem is clearly illustrated in U.S. Pat. No. 4,883,096.

It would be desirable to provide a papermaking fabric with a longitudinal suture loop that is free of torsional moments and / or twists.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a papermaking base fabric having a flat monofilament warp yarn system (hereinafter referred to as MD) laminated so as to control the permeability of the base fabric. To provide. In the weaving method of the present invention, the use of a high aspect ratio is applied as a structural weaving configuration. The MD yarn system is composed of vertically stacked upper and lower yarns. Preferably, the upper MD yarn defines a floating yarn on the top surface of the base fabric, and the upper MD yarns
The pair is vertically stacked on the lower MD yarn. The lower MD yarn is woven to provide a floating yarn on the bottom surface of the base fabric based on the inverse image of the upper MD yarn, or is subjected to different repetitions to provide a different surface on the bottom surface of the base fabric. Can be woven based on

At least the upper MD yarns are flat monofilaments woven in contact with each other so as to reduce the permeability of the base fabric and to secure the laminated pairs of MD yarns in longitudinal alignment. In a preferred embodiment, yarns of the same type and size are used throughout the warp yarn system, the top and bottom MD yarns both being adjacent to the adjacent top and bottom MD yarns. It is woven.
The laminated, adjacently woven longitudinal system is stably fed and allows the MD yarns to have a relatively high aspect ratio, ie, a cross-section width to height ratio of 3: 1 or more. In addition,
The aspect ratio is preferably in the range of about 2: 1 to 6: 1. Further, the warp threads define a series of vertically threaded annular threads at opposing ends of the backing. The end of the lower MD yarn is moved,
The upper MD yarns are stiffened at their back and are re-woven into the backing ends based on the spacing provided by the ends of the aligned lower MD yarns. The lower MD yarn is woven based on the inverse image of the upper MD yarn such that the shrinkage of the upper MD yarn corresponds to the weaving style spacing of the lower MD yarn on which the upper MD yarn is woven back. This improves the strength of the seam.

[0017] The non-annular upper MD yarns are preferably woven back within the space spaced by aligning the respective lower MD yarns. Preferably, at least the upper MD yarns are woven adjacent to each other to secure the alignment of the MD yarn pairs stacked in the longitudinal direction and the vertical alignment of the tubular ends. In a preferred embodiment, yarns of the same geometry and size of the same type of material are applied through the warp yarn system, and the top and bottom MD yarns are both attached to the top and bottom MD yarns, respectively. It is woven adjacent to it.

It is an object of the present invention to provide a papermaking base fabric having controlled permeability along with woven flat warp yarns.

It is a further object of the present invention to provide a low-permeability backing fabric entirely composed of monofilament yarns without using bulky stuffed yarns and without impairing strength or stability. It is in.

Other objects and advantages will become apparent from the preferred embodiments described later.

[0021]

In order to achieve such an object, the present invention provides a flat monofilament MD yarn (2) woven into a system of CMD yarns (21a, 21b).
An industrial backing (20) for a papermaking backing having an opposing end provided with the system of (2, 23, 24, 25), wherein the MD yarn is rearward a predetermined distance from an end of the backing. A pair of vertically aligned upper and lower MD yarns (22 and 23, 24 and 25) with a lower MD yarn (23) aligned with each other, and from the upper MD yarn (22) to each of the base fabrics. A series of orthogonal annular portions are formed on the end, and the upper M
The D yarn (22) has no ring shape at the rear, and the lower M
It is woven directly under the CMD yarns (21a, 21b) in the space provided by the D yarn (23).

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1, 2, and 3a, a cross-process (hereinafter referred to as CMD) yarn 11, 1 is shown.
2, a papermaking dry base fabric 10 having an upper layer, a middle layer, and a lower layer is shown, and CMD yarns 11, 12, 13 are shown.
Are interwoven with the structure of yarns 14 to 19 continuously knitted in a selected repeating pattern (pattern). MD yarn structure is CM
Upper MD yarn 14,1 interwoven with D yarns 11,12
6, 18 and the lower MD yarns 15, 17, 19 interwoven with the CMD yarns 12, 13.

The upper MD yarns 14, 16, 18 are
The knuckle is formed between the lower side of one CMD yarn 12 of the intermediate layer and the lower side of one CMD yarn 11 in the intermediate layer.
After being woven on the upper surface of the base fabric 10, the floating yarn is defined on the upper surface of the two CMD yarns 11 which ascend to the surface of the base fabric 10 and repeat the continuation of the yarn. The floating yarns on the upper CMD yarns 11 of the upper MD yarns 14, 16, 18 are staggered so that all the CMD yarns 11, 12 of the upper and middle layers are retained in the fabric structure.

As will be appreciated by those skilled in the art, FIGS.
And 3a will be the upper surface of the fabric with the twill pattern. Although the two float yarn woven patterns represented in FIGS. 1, 2, and 3a are preferred embodiments,
For those skilled in the art, the length of the float and the M
Other patterns, twill weaves and non-twill weaves can be created by selecting the number of D yarns and the order of the MD yarns as desired.

As best shown in FIGS. 2 and 3a, the lower MD yarns 15, 17, 19 are
It is woven in a vertically stacked relationship directly below 4,16,18. The lower thread is woven into an inverted image of the corresponding upper thread. The individual MD yarns 15, 17, 19 on the lower side float below the two lower CMD yarns 13 and form one CM yarn in the fabric.
Rises above the D thread 13 and then CMD of one of the middle layers
A knuckle is formed around the yarn 12, after which the yarn returns to the lower surface of the fabric and the next two CMD yarns 13 in the lower layer
Continuation of the repetition of the float under.

For each pair of stacked yarns, the internal knuckles formed around the CMD yarns 12 in the middle layer by one MD yarn are hidden by the floating yarns of the other MD yarns. For example, the lower MD yarn 1 in FIGS.
5 is depicted as weaving a knuckle on the CMD yarn 12 while the MD yarn 14 is weaving its floating yarn on the CMD yarn 11, thereby allowing the inner portion of the lower MD yarn 15 to be woven. The knuckle is hidden. 1 and 3a, the upper MD yarn 18 is the lower CMD yarn 1
It is depicted as weaving an internal knuckle under the CMD yarn 12 while it is hidden by the lower MD yarn 19 by floating below 3.

The upper MD yarns 14, 16, 18 are woven adjacent to each other. This maintains their respective parallel working direction alignment and reduces permeability. Such close weaving of the machine direction paper is disclosed in U.S. Pat. No. 4,290,209.
It is known in the art as 100% warp filling as described in US Pat. As taught (and used herein), the actual warp count in one fabric can vary between about 80% to about 125% in a single layer, and always 100% warp. Filling is considered.

The packing of the MD yarns 14, 16, and 18 also results in the MD yarns 15, 17, 19 being replaced by the MD yarns 14, 16, 18
Under their stacking position. MD yarns 15, 17, and 19 are MD yarns 14, 16,
And 18 are preferably the same size, so that they are woven into a 100% warp fill. this is,
The overall fabric of the preferred embodiment results in having a 200% warp fill of MD yarns.

The lower MD yarns 15, 17, 19 are also 10
Since they are preferably woven into a 0% warp fill, they similarly have the effect of maintaining the stacking relationship of the upper MD yarns 14, 16, 18 with respect to the lower MD yarns 15, 17, 19. Therefore, individual MD yarn pairs 14 and 15, 16
And 17, 18, and 19 are doubly fixed in place, resulting in enhanced fabric stability.

As is evident in US Pat. No. 4,290,209, it has been recognized that machine direction flat yarns are woven in closer contact around the machine direction transverse yarns than round yarns. . That said, in order to ensure the stability of the overall fabric, an aspect ratio of 3: 1 is seen as a practical limit for yarns woven in this manner. The laminated MD yarn structure is preferably in the range of 2: 1 to 6: 1 to ensure fabric stability and machine direction strength and more effectively control permeability, with an increased aspect ratio Allows the use of yarn.

The high aspect ratio of MD yarns results in reduced permeability. High aspect ratio yarns are wider and thinner than conventional flat yarns having an aspect ratio of less than 3: 1 and the same cross-sectional area. An equal cross-sectional area means that the yarns to be compared have substantially the same linear strength. The greater width of the high aspect ratio yarns results in a reduction in the weave in the width of the fabric as compared to conventional yarns, resulting in fewer openings through which fluid can flow through the fabric. The relative thinness of the high aspect ratio yarns allows for more effective placement, or support, of the flat MD yarns against the machine direction transverse yarns, which reduces the crossover between the machine direction yarns and the machine direction transverse yarns. Reduce dimensions.

For example, FIG. 3b shows a single layer of flat machine direction warp yarn having a cross-sectional area width of 1.5 units and a cross-sectional area height of 1 unit, ie, an aspect ratio of 1.5: 1. The fabric woven into the tissue is shown. Such a fabric is replaced by a fabric having the current doubly stacked MD yarn texture with MD yarns that are twice as wide, ie, 3 units, and half as high, ie, 0.5 units. I can do it. Such MD yarns have an aspect ratio that is 4 times greater than 6: 1, as shown in FIG. 3a.

The thinner and wider MD yarns control the permeability more effectively, and the cross-sectional area of the MD yarns at the width of the fabric remains the same, so that the mechanical strength of the fabric remains essentially unchanged. . For the above-described example shown in FIGS. 3a and 3b, a conventional single MD yarn fabric is 9 square units, ie, 9 × 9 (1 × 1.5 units) cross-sectional areas of the fabric width. The unit has six conventional continuous flat warp yarns. Thinner and wider high aspect ratio yarns woven as continuous stacked MD yarns define a fabric having three stacked MD yarn pairs on a fabric width of 9 units. Thus, such a fabric also has 9 square units over a fabric width of 9 units, ie (3 × (0.5 units × 3 units)).
+ (3 × (0.5 units × 3 units)). In one example, the fabric is woven according to FIGS. 1, 2, and 3, where the CMD yarns 11, 12, 13
Is a polyester single fiber yarn having a diameter of 0.6 mm,
It is interwoven with MD yarns, which are flat polyester monofilament yarns having a width of 1.12 mm and a height of 0.2 mm. Therefore, the aspect ratio of the flat MD yarn is 5.6: 1. This woven fabric has a 40 PLI (pounds per
linear inch (approximately 2.54 cm): loom tensile force of 1 inch (about 2.54 cm) and 12.5 C per inch (approximately 2.54 cm) per layer (3 layers).
4 per inch (about 2.54 cm) with MD weft
Woven with eight warp ends.

The woven fabric is heat set in a conventional heat setting apparatus in accordance with temperature, tensile force, and time conditions within the ranges conventionally known for polyester monofilament yarns. For example, a conventional polyester fabric is 36 degrees Fahrenheit.
0 to 380 degrees Fahrenheit, 6 to 15 PLI (po
unds per linear inch (about 2.5
4 cm): tensile force in pounds per primary inch) and heat set within parameters of 3-4 minutes time. Nevertheless, thanks to these stable structures, the fabrics of the present invention have greater tolerance to variations in heat setting parameters. This fabric is manufactured by the American Society for Testing and Materials ASTM D-16.
6000 PSI (po) measured according to the 82-64 standard
undsper square inch (2.54c
m): pounds per square inch). The fabric was pulled less than 0.2% in length during heat setting. As a result, fabric production in accordance with the teachings of the present invention achieves the desired dimensional characteristics with much higher reliability than conventional fabrics. After heat setting, the fabric is 1 inch per layer (approximately 2.54 c
m) with 12.5 CMD yarns, where 106% for both upper and lower MD yarns
The actual warp filling for the fabric is 212%. Finished fabric is ASTM
According to the D-737-75 standard, 83 CFM (about 0.42164 cm ³ / sec / c) was measured.
m ² ).

As shown in FIG. 4a, when the fabric 10 is woven, the three layers of CMD yarns 11, 12, 13 will be compressed. This compression along the relatively thin dimensions of the MD yarn reduces the thickness of the fabric. Thus, the overall thickness of the fabric is kept relatively low and is not much greater than conventional fabrics that are woven without laminated MD yarn pairs. In the example described above, the thickness of the finished fabric is 0.05
0 inches (about 0.127 cm).

If the upper MD yarns 14, 16, 18 or the lower MD yarns 15, 17, 19 are 100%
It will be appreciated by those skilled in the art that when woven with a warp fill, the overall warp fill for the laminated fabric will be much greater than 100% and will contribute to a reduction in the permeability of the fabric. Would. The fabric of the above example with the laminated MD yarns is filled with warp strands and lateral undulations.
125% of the non-laminated MD yarns provided by
Is recognized as having a much higher percentage of warp filling than a fabric having an actual warp filling.
Even if 200% warp filling is preferred, 1
By using a yarn that is narrower than an MD yarn woven with a 00% warp fill, either the upper or lower MD yarn is less than 100% filled with the other MD yarn less. Fabric can be woven. For example, the upper thread 1
4, 16 and 18 are set to a width of one unit, and the lower yarns 15, 17 and
19 is 0.75 units wide, which results in approximately 175
% Warp filling. Such variations can be used to achieve a selected degree of permeability. Such variations can also be employed to make a forming fabric. In such cases, the lower MD yarn is woven with a 100% warp fill to define the working side of the fabric, and the upper MD yarn is woven with a substantially lower percentage fill to provide a more open paper forming surface. Create.

The stacked pair of MD weave allows the formation of orthogonal seam loops in the MD yarn.
4a to 4d, after the woven fabric is woven and heat set (FIG. 4a), the CMD yarn is exposed and removed from the crimped MD yarns 14, 15 (FIG. 4).
b). One of a pair of stacked yarns, for example, the lower MD yarn 1
5 is woven back in a selected distance away from the other exposed MD yarn 14 of the MD yarn pair in the direction in which the fabric is woven, in a direction opposite to said direction from this loop. After returning to the predetermined distance, the mowing is performed, and a space is opened between the CMD yarns as shown in FIG. 4c. The upper MD yarn 14 is then rewoven by the lower MD yarn 15 into the space opened in the fabric pattern, thereby forming a loop L on the end of the fabric, as shown in FIG. 4d. Is done. Preferably, between 0.5 to 5.0 inches (about 1.27 to about 12.7 cm) of the overlying yarn 14 is woven back into the fabric to create sufficient strength for the end loops, Ensuring that the free ends of the MD yarns 14 are anchored in the weave of the fabric. The inverted image weave is the upper M
Allowing the crimp of the D thread 14 to fit into the space opened by the lower MD thread 15 further enhances the strength of the end loop.

As shown in phantom in FIG. 4d, adjacent pairs of yarns 16, 17 are treated in a similar manner. That said, the upper thread 16 recreates the loop,
And when it is woven back into the fabric, it is pulled against the CMD yarn. In a preferred embodiment in which the upper MD thread is woven with 100% fill, thread packing secures the orthogonal seam loop.

To achieve a uniform seam for a fabric woven according to the weave pattern depicted in FIG. 1, the individual upper MD yarns 14 form a loop while the remaining upper MD yarns form a loop. Yarns 16 and 18 are CMD at the end of the fabric
Woven back to the yarn. Therefore one of all these
The upper MD yarn of the seed defines a loop, and an array of loops is created on each end of the fabric. The seam is
It is interwoven with the opposing array of loops and assembled by inserting a pintle thread between the interwoven loops.

[0040] Preferably, all of the loop forming yarns 14 are woven back into the fabric approximately the same distance to create sufficient strength to prevent the loops from being pulled apart during normal use.
The non-loop forming yarns 16, 18 are preferably woven back a short distance since no load is placed on these yarns during use. For example, the upper MD yarn 14 is unwound approximately 3 inches, the MD yarn 16 is unwound approximately 2 inches, and the MD yarn 18 is approximately 1 inch. 54cm) Woven back. The individual yarns 15, 17, 19 of the lower layer are these MD yarns vs. yarns 14, 17,
Adjusted to complement 16, 18 individual backstrips.

FIGS. 5a and 5b respectively show a conventional seam loop 50 and the orthogonal seam loop L of the present invention compared thereto.
Are illustrated. In the conventional loop forming technology,
The MD yarn 51 is woven back into the fabric near itself, thereby imparting twist and / or torque to the loop structure 50. In the present invention, the MD thread is looped directly beneath itself and does not have any lateral offset that would twist or torque the stitch loop.

Referring to FIGS. 6, 7, and 8, there is shown a second preferred embodiment of a fabric 20 in accordance with the teachings of the present invention. The papermaking base fabric 20 includes single-layer CMD yarns 21a and 21b interwoven with the structure of the laminated MD yarns 22 to 25 woven in a selected repeating pattern.
The MD yarn structure includes upper MD yarns 22, 24, and the upper MD yarns 22, 24 are the next one CMD yarn 21.
a to form a knuckle under a
The woven yarn is defined on the upper surface of the fabric 20 by continually repeating the weaving over the three CMD yarns and then back up over the next three CMD yarns.

The lower MD yarns 23, 25 are woven in a vertically stacked relationship directly below the respective upper MD yarns 22, 24. The lower MD yarns are woven into an inverted image of their respective upper MD yarns. Individual lower MD yarns 23,2
5 floats beneath the three CMD yarns and has a knuckle (knuc)
kle), is woven up around the next one CMD yarn 21a, and then continues to float under the next three CMD yarns.

As can be seen with respect to FIGS. 6 and 8, the knuckle formed is the upper M
The floating yarns defined by the D yarns 22 and 24 respectively hide the floating yarns. Similarly, the knuckle formed by the upper MD yarns 22 and 24 is changed to the lower MD yarns 23 and 24.
Each is hidden by 25 floats.

The height of the fabric near the knuckle region shown in FIG. 8 is the non-knuckle (kn) shown in FIG.
ackle) tends to be somewhat larger than the height of the woven fabric in the CMD yarn 21b. That said,
C around which a knuckle is formed
The MD yarn 21a is crimped to reduce the height of the fabric in the area as shown in FIG. Further, a slightly larger diameter CMD yarn is shown in FIG.
It is preferably used as b and is not woven around as a knuckle with MD yarns to eliminate any differences in fabric height. The diameter of the larger CMD yarn 21b is preferably equal to the diameter d of the smaller CMD yarn 21a plus the thickness t of the MD yarn.

In one example, the fabric is woven according to FIGS. 6-9, where the CMD yarns 21a, 21b
MD yarn 2 is a polyester single fiber yarn having a diameter of 0.6 mm and 0.8 mm, respectively, and is a flat polyester single fiber yarn having a width of 1.12 mm and a height of 0.2 mm.
It is mixed with 2-25. Therefore, the aspect ratio of the flat MD yarn is 5.6: 1. The woven fabric is 40 PLI (p
sounds perinchear inch (about 2.5
4 cm): Loom pulling force in pounds per primary inch) and a total of 20 CMs per inch (about 2.54 cm)
It is woven with a total of 48 warp ends per inch with D-weft. The permeability in the final fabric is 90 CFM (about 0.4572 cm ³ / sec)
/ Cm ² ).

In another example, the woven fabric is woven according to FIGS. 6, 7, and 8, where the CMD yarn 21
Reference numerals a and 21b denote polyester single fiber yarns each having a diameter of 0.7 mm, and MD yarns 22 to which are flat polyester single fiber yarns having a width of 1.12 mm and a height of 0.2 mm.
It is mixed with 25. Therefore, the aspect ratio of the flat MD yarn is 5.6: 1. The fabric is 1 inch (about 2.5
It is woven with 22 CMD wefts per 4 cm). The fabric has been heat set using conventional methods. The fabric has a modulus of 600 PSI.
Is shown. The fabric is pulled less than 0.2% in length during heat setting.

Finally, the woven fabric has 22 CMD yarns per inch (about 2.54 cm) with 106% MD warp fill for both the upper and lower MD yarns, and as a result, Results in an actual warp filling of 212%. The final fabric is 0.048 inch (about 0.12
2 cm) and 60 CFM (about 0.3048 cm ³ /
sec / cm ² ).

As best shown in FIG. 9, high aspect ratio yarns 22-24 are effective in fabric construction in CMD.
The thread 21a is tightened. This tightening effect can be quantified in terms of the value of the contact angle θ and the area of the contact tightening, and the CBA is as follows.

CBA = πd (θ / 360 °) w where d is the diameter of the CMD yarn, θ is the degree of contact between the MD yarn and the CMD yarn, w is the width of the MD yarn, and π is the width of the MD yarn. It is a constant pi.

The degree to which the MD yarns 22 to 25 are in contact with the CMD yarn 21a depends on the gap between the CMD yarns in the weave. For the example described above, CMD yarns of 0.6 mm and 0.8 mm diameter are alternately employed with MD yarns of 0.2 mm thickness, and the above-mentioned degree of curvature reduces the number of weft yarns of the CMD yarn by one.
A preferred range between 60 ° and 180 ° can be maintained by varying from 14 lines per inch to a maximum of 28.22 lines per inch.

In a preferred embodiment in which the number of weft yarns is 20 per inch (about 2.54 cm), the contact degree θ
Is approximately 101 °. This means that each knuckle (kn
ackle) with a clamping contact area of approximately 0.79 m
and m ^2.

The use of a high aspect ratio yarn, ie a yarn having a width: thickness ratio of at least 3: 1, results in increased clamping contact of the flat MD yarn to the CMD yarn 21a. . This is relatively exemplified by modifying the metering CBA for the contact tightening area so that it can be specified in the MD Yarn Thickness section.

Since the MD yarn width w is equal to the MD yarn thickness t multiplied by the aspect ratio, w> 3t for yarns having an aspect ratio greater than t3: 1. Thus, fabrics formed according to the techniques of the present invention using high aspect ratio MD yarns have enhanced tightening of CMD yarns such that CBA> πd (θ / 360 °) 3t with MD yarns.

As best shown in FIG. 10, the stitch loop is formed by the upper MD thread 22. The individual lower MD yarns 23 have been trimmed a selected distance from the fabric edge, and the upper MD yarns 22 have been woven back into the space opened by the trimmed lower MD yarns 23.

The upper MD yarn 24 is similarly woven back into the space opened by the cut lower MD yarn 25. Nevertheless, the upper MD yarn 24 is woven back to the terminal CMD yarn 21b.

As shown in FIG. 11, a row of seam loops is formed on each of the opposite ends 27, 28 of the fabric. When the fabric is placed on a papermaking machine, the individual end loops formed by the MD yarns 22 are knitted together, and a pintle 29 is inserted into them and knitted together. Fix the rows of loops to each other.

Since the seam loop L is formed by the MD yarn 22 which is woven back just below itself, no side twist or torque is applied on the loop, and the loop is laid in the plane of the woven fabric. Direction). This facilitates the mutual knitting of the rows of loops of the opposing ends 27, 28 of the fabric. As shown in FIG. 10, the orthogonal loop is 100% MD yarns 22, 24.
Warp filling is particularly preferred when adjacent loops are separated by individual MD yarns of the same width as the loop MD yarns 22. Side torque or torsion on the seam loop may be
The stitching process is made more difficult if the loop receiving gap between the loops of one fabric end is substantially the same width as the loop on the opposite fabric end.

For the fabric depicted in FIGS. 6-11, the looped MD yarn 22 is approximately 2 inches (approximately 5.08
cm) preferably unwoven, non-looping MD
Preferably, the yarn 24 is unwound 1 inch (about 2.54 cm).

Referring to FIG. 12, there is shown a papermaking base fabric 30 according to a third embodiment. The base fabric 30 comprises a single layer of CMD yarns 31 interwoven into a stacked pair of flat single fiber yarns in a predetermined repeating pattern. More specifically, only one pair of stacked MD yarns with an upper MD yarn 32 and a lower MD yarn 33 is shown. Upper M
The D yarn weaves the floating yarn on the two CMD yarns 31, and the next CMD yarn
A single knuckle is formed under the thread 31 and thereafter is repeated. Similarly, the lower MD yarn is composed of two CMD yarns 31.
It is woven into an inverted image of the upper MD yarn woven under, forming a knuckle on the next CMD yarn 31 and then returned to the bottom surface of the fabric. Since the repetition of both the upper and lower MD yarns involves three CMD yarns 31, a total of three different stacked yarn pairs have an MD yarn weave pattern.

The woven fabric is woven according to FIG. 12, where the CMD yarn 31 is a polyester monofilament yarn with a diameter of 0.7 mm, a flat polyester monofilament having a width of 1.12 mm and a height of 0.2 mm. It is interwoven with MD yarn which is a fiber yarn. Therefore, the aspect ratio of the flat MD yarn is 5.
6: 1. This fabric is woven at 48 warp ends per inch under a loom pull of 60 PLI and 18 CMD yarns per inch. The fabric has been heat set using conventional methods. The woven fabric has a modulus of 6000 PSI (mo
durus). The fabric is pulled less than 0.2% in length during heat setting. Ultimately, the fabric is 106 fold for both the upper and lower MD yarns.
1 inch with a% MD warp filling
It has 18 CMD yarns per thread, resulting in a 212% actual warp fill for the fabric. The final fabric, the height of 0.046 inches (approximately 0.117cm) and 66CFM (about 0.33528cm ³ / sec / c
m ² ).

Referring to FIG. 13, there is shown a papermaking base fabric 40 according to a fourth embodiment. The base fabric 40 includes an upper layer, an intermediate layer, and a lower layer of the CMD yarns 41, 42, 43 interwoven in a laminated pair of flat single fiber yarns in a predetermined repeating pattern. More specifically, the upper MD yarn 4
Only one pair of stacked MD yarns with 4 and the lower MD yarn 45 is shown. The upper MD yarn weaves the floating yarn over the upper two CMD yarns 41 and the floating yarn below the next yarn 41 and the middle layer yarn 42 to form a single knuckle;
Float yarns are woven under the next CMD yarn 41, and then rise to the top surface to continue repeating. Similarly, the lower MD
The yarn is woven into an inverted image of the upper MD yarn woven under the lower two CMD yarns 43, forming a knuckle over the next CMD yarn 43 and the middle layer yarn 42, and Returned to the bottom of the fabric and repeated. The repetition of both the upper and lower MD yarns results in four upper and lower MD yarns 41,
As such, a total of four different stacked yarn pairs have an MD yarn weave pattern.

The woven fabric is woven according to FIG. 13, where the upper and lower CMD yarns 41, 43 are 0.62 mm diameter multifilament polyester yarns covered with nylon, and the middle CMD yarn 42 is 0.5mm
Polyester single fiber yarn. CMD yarn 42 of the middle layer
Is interwoven with MD yarns 22-25, which are flat polyester monofilament yarns having a width of 0.60 mm and a height of 0.38 mm. Therefore, the aspect ratio of the flat MD yarn is 1.58: 1. This fabric has a loom pull of 40 PLI and 15 CMD yarns per inch (about 2.54 cm) per layer and 96 per inch (about 2.54 cm).
Woven at the warp end of the book. The fabric has been heat set using conventional methods. Finally, the fabric has 15 CMD yarns per inch per layer (about 2.54 cm) with 113% MD warp filling for both the upper and lower MD yarns, and as a result, Is 226%
Is the actual warp filling. The final fabric is 0.075
It has a height of inches (about 0.191 cm) and an air permeability of 60 CFM (about 0.3048 cm ³ / sec / cm ² ).

FIGS. 14, 15 and 16 show the fifth and fifth embodiments of the present invention.
The sixth and seventh embodiments are shown. FIG. 14 shows the weave of relatively long floating yarns on both sides of the fabric; FIG. 15 shows the weave of a stacked pair of MD yarns (wea).
v.) shows how floats of different lengths can be defined on opposite sides of the fabric; and FIG. 16 shows the weave of a stacked pair of MD yarns.
Can be used to construct a fabric having an MD knuckle on one side of the fabric.

The relatively long floats dominating the surface of the dry fabric are convenient for both the paper transport side and the machine side of the fabric. On the paper transport side, long floats create more contact area with the paper and increase heat transfer. On the machine side, long floats create an increased support surface and contact area, reducing bouncing and flutter. The laminated pair of MD yarns is convenient to allow defining different surfaces on the top and bottom sides of the fabric. Thus, fabrics formed in accordance with the teachings of the present invention can be used for other industrial purposes, such as, for example, drying sludge.

Referring to FIG. 14, three layers of yarns 51,5
A fabric 50 with each of 2, 2 and 53 is shown. In this configuration, a pair of MD yarns, such as, for example, a pair formed by an upper yarn 54 and a lower yarn 55, defines a relatively long float on both the top and bottom surfaces of the fabric. The upper yarn 54 is woven on the upper five CMD yarns 51,
It is dropped into the fabric to form a knuckle under one CMD yarn 52 in the middle layer and the next yarn 5 in the upper layer.
Woven under one and then repeat this. The lower MD yarn 55 is woven into an inverted image under the lower five CMD yarns 53 and is raised into the fabric over the next CMD yarn 53 to form one CMD yarn 52 in the middle layer. A knuckle is woven on the woven fabric, and then dropped on the bottom surface of the woven fabric, and is continuously repeated.

In such a structure, the stacked M
Six pairs of D yarns are used in the repetition of the fabric,
It is woven sequentially in a predetermined order to create the desired pattern on the surface of the fabric dominated by the floats of the MD yarns.

The embodiment shown in FIG.
In the woven fabric 60, the MD yarns are woven in five floating yarn repeats on the upper surface of the woven fabric, and are woven in two floating yarn repeats on the bottom surface of the woven fabric. For example, the upper M
The D yarn 64 is interwoven with the upper and middle CMD yarns 61 and 62 in the same manner as the upper MD yarn 54 with the CMD yarns 51 and 52 with respect to the fabric 50 in FIG. That said, the lower MD yarn 65 forming a pair stacked with the upper MD yarn 64 is woven in two floating yarn bottom repeats for the lower and middle CMD yarns 63,62. For example, the lower MD yarn 65 floats below the lower two CMD yarns 63, and the next CMD yarn 63
To form a knuckle on one of the CMD yarns 62 in the middle layer, and then dropped onto the bottom of the fabric 60 to continue the repetition.
As in the other embodiments described above, the internal knuckle formed by the lower MD yarn is concealed by the upper MD yarn of each stacked pair, and vice versa.

The configuration shown in FIG. 15 allows for different surfaces to be defined on the top and bottom of the fabric while using the transfer of pairs of stacked MD yarns.

The embodiment shown in FIG. 16 discloses another example of a fabric 70, which has five floating MD yarns that dominate the top surface of the fabric, Knuckles are provided on the lower surface of the fabric.
This type of construction constitutes a fabric in which the relatively long floated upper surface of the fabric is used as the machine side of the fabric and the knuckle lower surface of the fabric is used as the paper forming side. It is advantageously used for

The woven fabric 70 is interwoven with a stacked pair of MD yarns to define this structure.
2,3 layers are included. MD vs. 7 stacked
Only one pair of 4,75 is drawn for clarity. The upper MD yarn 74 is the fabric 5 shown in FIG.
In the same manner as the upper MD yarn 54 with respect to 0, the CMD yarns 71 and 72 of the upper and middle layers are woven into five floating yarn patterns. The lower MD yarn 75 is the individual MD yarn 74
Of the middle and lower layers below the upper surface floats of each pair of
Three internal knuckles for the yarns 72, 73 (knucks)
le) and three lower surface knuckles. The repetition of the upper MD yarn is the upper 6 C
It is specified for the MD yarn 71 and the repetition of the lower MD yarn is specified for only two CMD yarns 73 in the lower layer. Thus, as described above, the MD can be arranged such that the desired pattern is formed on the upper surface of the fabric.
Stacked MD comprising yarn system
There are six different pairs of yarn. In defining the relationship of the lamination pairs, the repetition of the upper MD yarn is generally evenly divisible by the repetition of the lower MD yarn or by a factor of two for the laminated weave. For example, referring to FIG. 12, the repetition of the upper MD yarn is six CMD yarns in the upper layer that can be evenly divided by the repetition of the lower MD yarn, which is the three CMD yarns in the lower layer.

With respect to the eighth embodiment shown in FIG. 17, a single layer of CMD yarn 81 and MD yarns 82, 83
A fabric 80 is depicted having a pair stacked on behalf of the fabric 80. The upper MD yarn 82 has three CMD yarns 8
CMD yarn 81 with repetition occurring for
Weaving two floats on top. The lower MD yarn 83 is
Five floating yarns are woven below the CMD yarn 81 with the repetition of the six CMD yarns 81. Therefore, in the woven fabric 80, the repetition of the three upper MD yarns is twice the repetition of the six lower MD yarns.

Various other tissues (w) employing the paired weave structure of the present invention.
eave) patterns can be constructed within the scope of the present invention. For example, in some applications, the MD yarn surface may be 6
It may be preferable to float on a book or more CMD yarns. Such fabrics are easily constructed according to the teachings of the present invention.

[0074]

According to the present invention, it is possible to provide a papermaking base fabric having controlled permeability together with woven flat warp yarns. Further, according to the present invention, it is possible to provide a low-permeability base fabric composed entirely of monofilament yarn without using bulky stuffed yarn and without impairing strength or stability. .

[Brief description of the drawings]

FIG. 1 is a schematic view of a papermaking base fabric formed according to the technique of the present invention.

FIG. 2 is a sectional view of the base fabric taken along line 2-2 shown in FIG. 1;

3A is a cross-sectional view of the base fabric taken along line 3-3 shown in FIG. 1, and FIG. 3B is a cross-sectional view of a conventional weaving structure.

FIG. 4A is a diagram showing the yarn direction of the base fabric shown in FIG. 1 after completion of the base fabric in a state showing two representative stacked MD yarns, and FIGS. FIG. 2D is a diagram showing a circular ring form for the papermaking base fabric shown in FIG. 1.

FIG. 5 (a) is a perspective view of a conventional sewing annular MD thread,
(B) is a perspective view of a sewing circular vertical MD thread formed according to the present invention.

FIG. 6 is a schematic view of a base fabric according to a second embodiment formed in accordance with the present invention.

FIG. 7 is a sectional view of the base fabric taken along line 7-7 of FIG. 6;

FIG. 8 is a sectional view of the base fabric taken along line 8-8 in FIG. 6;

FIG. 9 is a perspective view of the base fabric shown in FIGS. 6 to 8;

FIG. 10 is a view showing an annular end constituted by one MD yarn and showing the yarn direction in the completed base fabric shown in FIG. 6;

FIG. 11 shows a state immediately before the both ends are stitched with pins.
The top view of the opposing end of the base fabric comprised corresponding to FIG.

FIG. 12 shows only a pair of MD yarns stacked,
The schematic diagram of the 3rd embodiment of the base cloth formed according to the technology of the present invention.

FIG. 13 shows only a pair of MD yarns stacked,
The schematic diagram of the base cloth of the fourth embodiment formed corresponding to the technology of the present invention.

FIG. 14 shows only a pair of MD yarns stacked,
The schematic diagram of the base cloth of the fifth embodiment formed corresponding to the technology of the present invention.

FIG. 15 shows only a pair of MD yarns stacked,
The schematic diagram of the base cloth of the sixth embodiment formed corresponding to the technology of the present invention.

FIG. 16 shows only a pair of MD yarns stacked,
The schematic diagram of the base cloth of the seventh embodiment formed corresponding to the technique of the present invention.

FIG. 17 shows only a pair of MD yarns stacked,
The schematic diagram of the base cloth of the eighth embodiment formed corresponding to the technology of the present invention.

[Explanation of symbols]

 21a, 21b CMD yarn 22, 23, 24, 25 MD yarn

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho-51-139204 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21F 1/10-1/12 D21F 7 / 08-7/10

Claims (10)

(57) [Claims] 1. A CMD yarn (11, 12, 13; 21a,
21b) A papermaking fabric (10; 2) having a paired opposing ends with a system of flat monofilament MD yarns (14-19; 22-25) woven into the system.
In (0), the MD yarn (14-19; 22-25) is woven to form an end, and is cut off at a predetermined distance from an end of the base fabric, and the lower MD yarn ( 15,1
7, 19; 23, 25), a pair of upper and lower MD yarns (14 and 1) arranged one above the other.
5, 16 and 17, 18 and 19, 22 and 23, 24 and 25), and the end orthogonal to the direction in which the base fabric is woven is attached to the MD yarn (14; 22), an annular portion is formed at the end of the base fabric, and the upper MD yarns (14, 16, 18; 2) are formed.
2 and 24) into the spaces separated by the cut lower MD yarns (15, 17, 19; 23, 25), respectively, into these MD yarns (14, 16, 18; 22, 2).
4) The CMD yarn (11, 12, 13;
21a, 21b). 2. The CMD yarn system according to claim 1, wherein the CMD yarn system comprises:
2. The fabric according to claim 1, comprising a single layer of 1a, 21b). 3. The base fabric according to claim 1, wherein at least the upper MD yarn (22) has an aspect ratio of at least 3: 1. 4. The upper MD yarn (14; 2) having an annular portion formed at an end perpendicular to the direction in which the base fabric is woven.
2) are woven into the CMD yarns (11, 12, 13; 21a, 21b) directly below these MD yarns (14; 22) themselves, and all the lower MD yarns (15, 17) are woven. , 19; 23,2
5) is cut off at a predetermined distance from the end of the base cloth, and the remaining upper MD yarns (16, 18; 24) are directly under these MD yarns (16, 18; 24). 2. The base fabric according to claim 1, wherein the base fabric is woven with respect to the CMD yarns (11, 12, 13; 21a, 21b) and holds the endmost CMD yarns with the base fabric. 5. The upper MD yarn (14; 2) having an annular portion formed at an end perpendicular to the direction in which the base fabric is woven.
2) is woven back about the same distance into the end of the base fabric, this distance being the same as the remaining MD yarn (16,
18; 24) is larger than the unwound fabric, and the upper MD yarn (14; 22) forming the annular portion.
The lower MD yarn (15; 23) combined with
5. The base fabric according to claim 1, wherein the base fabric is trimmed at a distance greater than an end of the base fabric than the remaining lower MD yarns (17, 19; 25). 6. The fabric according to claim 4, wherein the actual warp filling of at least the upper MD yarns (22, 24) is in the range of 80% to 125%. 7. The lower MD yarns (23, 25) are woven with respect to the CMD yarns (21a, 21b) in a reverse image state of the upper MD yarns (22, 24) of the paired MD yarns. Item 5. The base fabric according to item 4. 8. There are two kinds of upper MD yarns (22, 24) in the repeating pattern of the base cloth, and one of the upper MD yarns (22) forms an annular portion. The base fabric according to any one of claims 1, 4, and 5, wherein the base fabric is provided. 9. There are three kinds of upper MD yarns (14, 16, 18) in the repeating pattern of the base cloth, and one of the upper MD yarns (14) is The base fabric according to any one of claims 1, 4, and 5, wherein the base fabric forms an annular portion orthogonal to the fabric. 10. Each of the opposed ends has a first MD yarn (14; 22) having an annular portion, and defines an annular portion at an end perpendicular to the direction in which the base fabric is woven. CMD directly below these MD yarns (14; 22).
21a, 21b) and each of the opposed ends is formed with an annular portion interspersed between the first MD yarns (14; 22). The second MD yarn (1
6, 18; 24), and the MD yarns (14, 16, 18, 18;
Directly below the CMD yarn (11,12,1).
3; The base fabric according to claim 1, which is woven with respect to 21a, 21b).