KR100661848B1 - Composite molded fabrics with warp triples - Google Patents

Abstract

Molded fabrics having a paper side layer and a machine side layer include a first set of paper side layer wefts, a second set of machine side layer wefts, and a single set of warp triplets. In this fabric tissue pattern, each warp of each warp triplet is woven with the paper side weft yarn to in turn occupy sections of the uninterrupted warp path of the paper side layer surface, and is also woven only with at least one single machine side weft. All. Each section of the uninterrupted inclined path is separated by at least one paper side layer weft. The weaving points of the machine side layers are spaced at regular intervals. After thermal curing, the fabric typically has an air permeability of about 7,500 to about 10,500 m ³ / m ² / hr. Paper products made using these fabrics have improved printability.

Paper machine, composite molding fabric, paper side layer, machine side layer, warp triplet

Description

Composite molding fabric containing warp triples {WARP TRIPLET COMPOSITE FORMING FABRIC}

The present invention relates to a woven molded fabric for use in paper machines. The molded fabric of the present invention essentially comprises at least two layers or sets of weft yarns, that is, a set of weft yarns in the paper side layer of the fabric and another set of weft yarns in the machine side layer of the fabric The yarn is woven with each warp of the warp triplet, which is a set of three warps. Thus, the fabric of the present invention visually appears to include at least two layers, but these layers are not separated, but are interconnected woven structures, and cannot be separated into two separate and freestanding woven structures.

Known composite molded fabrics comprise two essentially separate woven structures, each of which has its own set of warp and weft yarns and are woven in a pattern selected to optimize the properties of each layer. The paper side layer should, among other things, provide a minimal fabric wire mark to the initial paper web and provide adequate liquid drainage from the initial paper web. The machine side layer must be strong and durable, provide dimensional stability to the molded fabric to minimize fabric elongation and shrinkage, and be stiff enough to minimize curling at the fabric edges. Many fabrics of this type are disclosed in the literature and are used industrially.

The two layers of known composite molded fabrics are interconnected by additional binder yarns or inherent binder yarns. Additional binder yarns mainly serve to bind the two layers together, and inherent binder yarns not only contribute to the structure of the paper side layer but also to bind the paper side and machine side layers of the composite molded fabric together. The path of the binder yarn is arranged such that the selected yarn passes through both layers of the fabric and interconnects these layers into a single composite fabric.

In these known composite molded fabrics, additional weft binders are generally preferred over intrinsic weft binders because it was believed that the additional weft binders produced less discontinuities on the paper side surface of the composite fabric. Recently, single and paired intrinsic warp or weft binders have been proposed, but intrinsic weft binders have been found to cause changes in mesh uniformity in the machine cross direction. Composite fabrics with intrinsic weft bond yarns have been found to be susceptible to lateral shrinkage when subjected to tensile loads in paper machines. These intrinsic weft binders have been found to undergo internal and external wear and cause catastrophic delamination of the composite fabric. In addition, these fabrics are expensive to manufacture because of the need to weave additional weft yarns into the fabric structure to form the paper side layer and tie the paper side layer and the machine side layer together.

More recently, to overcome at least some of these drawbacks, it has been proposed to use inherent warp yarns in pairs or triplets. These two types of fabrics are disclosed in US Pat. No. 5,152,326 (in pairs), US Pat. No. 6,240,973 (in triplets), and US Pat. No. 6,202,705 (in triplets).

When using a pair, the advantage of the fact that two warp binding yarns can be arranged in succession to subsequent segments of the unbroken slope path of the paper side, each of the pairs The advantage is that the warp binding yarns have more flexibility in choosing where to interlacing with the machine side layer wefts. Thus, by increasing the amount of material that is usually written to wear out before catastrophic failure due to layer splitting occurs, for example, by reducing the wire marking of the initial paper web, the paper-side surface is reduced. It is possible to optimize to some extent and to improve the wear resistance of the machine side layer of the fabric. In these fabrics that use paired warp yarns, each of the paper side layer and the machine side layer has separate weft line systems, one of which lines the paper side layer structure, and the other side the machine side. Complete the hierarchy.

In the following description of the present invention, in the notation such as "2x2", it should be understood that the first number represents the number of healds required to weave the pattern, and the second number represents the number of wefts in the pattern cycle. Therefore, a 2x2 pattern requires two healds, and there are two wefts in the pattern circulation.

As described in US Pat. No. 6,240,973 and US Pat. No. 6,202,705, when using warp triplets, the fabric has only three sets of yarn, i.e., paper side weft set and machine side weft set and these It can be woven with only a single set of warps contributing to the structure of both layers, providing the advantage that the fabric structure can be simplified. By using warp triples such that each warp of the warp triple is woven separately from the paper side layer weft and in pairs with the machine side weft, it is possible to weave a fabric having acceptable papermaking properties. When interwoven with the machine side layer weft, the paired warp bends slightly outward toward the machine side surface of the fabric. This provides a wear surface that increases the wear resistance of the fabric and increases its fabric life.

The use of warp triples woven in pairs with machine side weft yarns results in less variation in the machine cross direction of the paper layer layer uniformity compared to conventional fabrics compared to the prior art fabrics, resulting in dimpling of the paper side surface. Less molded and molded fabrics with good resistance to lateral shrinkage are provided. It is possible to weave some of these warp triple fabrics from a single warp beam, since all warps follow essentially similar paths with the same path length in the weave structure.

However, composite molded fabrics woven using warp triples have still been found to be prone to papermaking of the paper side layer. As the slope passes from one surface of the fabric to another surface, for example from the surface of the paper side layer to the surface of the machine side layer, these slopes may impart some irregularity to the regular spacing of the paper side layer wefts. Can be. This causes a change in the shape and length of the drainage holes of the paper side layer of the molded fabric, thereby changing the drainage characteristics of the fabric. These changes can impose an unacceptable level of marking (so-called "wire mark") on the paper product produced.

It has been found that this level of change can be mitigated by interweaving at least each of the warp triples with machine side wefts. If such measures are taken, it is possible for each warp of each warp triplet to follow the same path in the tissue pattern, so that the locations of the weaving points can be made more uniform. As a result, the properties of the paper-side layer surface are improved to form a paper product more uniformly.

In addition, the present inventors carefully select the warp material used in the fabric of the present invention to quickly discharge an immature sheet into the center surface of the fabric structure without sacrificing the important mechanical properties of the fabric, in particular the modulus of elasticity. It has been found that it is possible to weave a fabric having a high paper side surface open area with sufficient drainage area. In the machine side layer and the central plane of the fabric with the higher density of the yarn, the fluid drainage is delayed slightly, so that pressure pulses caused by the supporting foils and blades of the molding provide an opportunity to maximize the molding benefits. Appeared to be.

The inventors have found that, as a warp of the fabric of the present invention, in order to provide equivalent mechanical strength properties, a yarn of relatively small diameter and high modulus of elasticity may be used instead of a conventional polyethylene terephthalate (PET) yarn having a relatively large diameter. okay. Thus, it is possible to use these small diameter yarns to provide a fabric having a relatively high paper side layer drainage area at low warp density at the paper side surface. This makes it possible to use a larger number of machine cross direction wefts than was possible in the paper side layer to increase the fiber support of the sheet and improve the molding. These extra wefts contribute to the overall fabric stiffness and stability needed for reliable service life (ie, "runnability").

Thus, the fabrics of the present invention can drain fluid from the sheet faster than was possible with conventional fabrics woven using coarser warp yarns, and provide more support for the papermaking fibers in the support material to improve the overall molding. Can provide. The use of these high modulus yarns also improves the fabric's resistance to damage due to high pressure showers such as those used to clean the fabric during use. In addition, these small diameter and high modulus slits are somewhat recessed into the machine side layer surface of the fabric due to the machine side layer design and the heat setting conditions used to treat the fabric after weaving. Following the heat fixation treatment, the weft side of the machine side of the fabric bends outwards or deforms, forming a wear surface that serves to protect the warp from wear during use. This feature serves to further increase the service life of these fabrics.

In a first embodiment, the present invention provides a composite molded fabric having a paper side layer and a machine side layer,

(i) a first set of paper side layer wefts,

(Ii) a second set of machine side layer wefts coarser than the paper side layer wefts, and

(Iii) a set of warp triples contributing to the structure of both the paper side layer and the machine side layer,

The three sets of yarns are woven together according to a repeating pattern,

(a) each warp of each warp triplet is woven with the paper side layer weft so as to occupy sections of a single uninterrupted warp path of the paper side layer,

(b) the order of the compartments is repeated as part of a repeating pattern,

(c) each compartment of the uninterrupted inclined path is separated from the next compartment by at least one paper side layer weft,

(d) each warp of each warp triplet is individually woven with a single machine side weft yarn at least once within the pattern cycle,

(e) within the repeating pattern of the fabric, the number of machine side layer wefts between the points at which successive warps from each warp triplet are respectively woven is constant,

(f) Within the repeating pattern of the fabric, there is provided a composite molded fabric characterized in that the path length of each warp of each warp triplet is the same.

In a preferred embodiment of the present invention, the fabric as it is woven and prior to heat set treatment has a warp fill of 100% to 125%.

In the molded fabric of the present invention, thermoplastic monofilaments are used for both warp and weft yarns.

In the first embodiment, both the weft and the warp yarns of the first and second sets are the same thermoplastic monofilament. It is preferred that both the weft and warp yarns of the first and second sets are polyethylene terephthalate monofilaments.

In the second embodiment, both the weft and the warp yarns of the first and second sets are not the same thermoplastic monofilament.

In a third embodiment, the first set of weft yarns comprises at least first and second subsets of weft yarns, wherein each subset of weft yarns consists of different thermoplastic monofilaments.

In a fourth embodiment, the second set of weft yarns comprises at least third and fourth subsets of weft yarns, each weft yarn being composed of different thermoplastic monofilaments.

In the fifth embodiment, the inclination is a thermoplastic monofilament having a higher modulus of elasticity than the thermoplastic monofilament of the paper-side layer weft yarn. It is preferable that the ratio of the elastic modulus of the warp yarn and the elastic modulus of the paper-side layer weft is about 4: 3.

In each of the first set of weft yarns, the second set of weft yarns and the warp yarns, it is preferred that the threads are all the same size.

It is preferred that the first and second sets of weft yarns are polyethylene terephthalate monofilaments.

The second set of weft yarns is preferably a yarn selected from the group consisting of polyethylene terephthalate monofilaments, monofilaments of a mixture of polyethylene terephthalate and thermoplastic polyurethane, polyamide monofilaments, and mixtures thereof. More preferably, in the second set of weft yarns, the third subset of weft yarns consists of a monofilament of a mixture of polyethylene terephthalate and thermoplastic polyurethane, and the fourth subset of weft yarns is a polyethylene terephthalate monofilament, poly Amide monofilaments, and mixtures thereof, the yarns of the third subset making up at least 50% of the second set of wefts in the machine side layer.

The inclination is preferably selected from the group consisting of polyethylene terephthalate monofilament, polyethylene naphthalate monofilament, and mixtures thereof.

The warp yarn is preferably selected from the group consisting of polyethylene naphthalate monofilament, polyethylene terephthalate monofilament, and mixtures of polyethylene naphthalate monofilament and polyethylene terephthalate monofilament.

The polyethylene monofilament is preferably polyamide-6 or polyamide-6 / 6 monofilament.

In another preferred embodiment of the present invention, the fabric after heat fixation has a paper side layer having an open area of at least 35% as measured by standard test procedures, the fabric having a warp filling rate of 100% to 110% , The fabric has an air permeability from less than about 10,500 m ³ / m ² / hr to about 3,500 m ³ / m ² / hr at a pressure difference of 127 Pa through the fabric as measured by standard test procedures. A suitable test procedure for measuring the air permeability of a fabric is ASTM D 737-96. The open area of the paper side layer was measured by the method described in CPPA data sheet G-18 using the top view of the paper side layer of the fabric.

The requirement of the present invention is that the warp triples are made per warp, and each warp of each warp triplet must occupy a portion of the uninterrupted warp path of the paper side layer tissue pattern that repeats within the fabric tissue pattern. Within the overall tissue pattern of the molded fabric, each warp of each warp triple passes through the machine side layer alone to be woven with at least one machine side weft to form a single bonded fabric. The interlacing position is a knuckle formed by interweaving individual warp yarns of each warp triplet with the machine side layer weft, so that all three warp yarns of each warp triple within the fabric tissue pattern cycle are machined. It will be woven at least once with the side weft. The number of interwoven points within the tissue pattern cycle is determined by the combination of healds required for the individual tissue patterns selected for the paper side and machine side layers. The location of the weaving points is chosen so that there is an equal number of machine side layer wefts between each weaving points and the points are spaced at regular intervals within the machine side layer.

In a preferred embodiment of the invention, the warp yarn of monofilament and the machine side layer weft of monofilament are made of different thermoplastic materials. For example, polyethylene terephthalate commonly used to weave molded fabrics provides monofilaments having an elastic modulus of about 1,400 kg / m 2 to about 1,550 kg / m 2, while polyethylene naphthalate has an elastic modulus of about 2,000 kg / m 2 It provides a monofilament having. An elastic modulus ratio of about 4: 3 has been found to be particularly beneficial.

Combinations of the thermoplastic seal materials of Table 1 below have been found to be suitable.

TABLE 1

Combination slope First weft Second weft A PET PET PET B PEN PET PET C PET PET PET / TPU D PET PET PET / TPU + PA6 E PET PET PET / TPU + PET F PEN PET PET / TPU G PEN PET PET / TPU + PA6 H PEN PET PET / TPU + PET I PEN PET PET + PA6 J PET PET PET + PA6

In Table 1,

PET: polyethylene terephthalate

PEN: Polyethylene Naphthalate

PEN / TPU: polyethylene terephthalate modified with thermoplastic polyurethanes (see US Pat. Nos. 5,169,171 and 5,502,120)

PA6: Polyamide-6

In Table 1, when a mixture of two yarns is used, for example as in combination D, the two yarns are preferably alternating.

When a combination of yarns with different modulus of elasticity is used, a relatively high modulus of warp fabric is applied to impart sufficient crimp to the machine side layer weft so that the machine side layer weft bends outward from the plane of the machine side layer. It has been found that it can be woven into the structure. By carefully selecting the heat fixation conditions after weaving, the crimp imparted to the machine side layer weft can be improved, which acts to incline the warp into the fabric structure to protect these warp from abrasion wear. This action also allows each warp of each warp triplet to follow a somewhat identical path within the fabric structure, which reduces the change in the paper side layer mesh, reducing the tendency of the fabric to cause wire marks. To help.

Thus, in the fabric of the present invention, it is evident that the weft yarn can be bent toward various structures that support the forming fabric of the paper machine forming part. This forms a wear surface on the machine side of the molded fabric. Machine-side layer weft yarns have a relatively high wear resistance, such as polyethylene terephthalate, a thermoplastic polypetane material described in US Pat. No. 5,169,171 and US Pat. No. 5,502,120, or polyamides such as polyamide-6 and polyamide-6 / 6. When including monofilaments, fabrics have a higher wear resistance and longer service life than fabrics woven without these machine side weft yarns.

Although the fabrics of the present invention may utilize different thermoplastic monofilaments in each of the first set of weft yarns, the second set of weft yarns, and the warp yarns, it is preferred that in each group of yarns all yarns have the same size. In addition, in order to obtain as uniform papermaking as possible, it is preferred that the first set of weft and warp yarns used in the paper-side layer are substantially the same size.

In the fabric of the present invention, neither the paper side layer nor the machine side layer includes the usual warp that is woven only with the paper side layer weft or the machine side layer weft. In the fabric of the present invention, the weft yarns of the first set of paper-side layers and the weft yarns of the second set of machine-side layers are held together by a single set of warp triplets within the overall tissue circulation pattern, thereby providing structural integrity of both layers. Contribute to the characteristics.

The length of the sections in the uninterrupted slope path of the paper-side surface occupied by each warp of the warp triples in turn, and the number of sections in one tissue pattern cycle can each be chosen in a wide range. For example, in the fabrics described in more detail below, all of these fabrics use a tissue pattern with six compartments, where the path that each warp of the warp triplet occupies in the tissue pattern cycle is substantially the same. In the uninterrupted oblique path of the paper side layer, each compartment generally occurs one or more times, for example at least twice in turn within each complete circulation of the molding fabric tissue pattern.

Each compartment in the uninterrupted oblique path of the paper side of the paper side layer is preferably separated from the adjacent compartment by one, two or three paper side layer wefts. More preferably, each compartment in the uninterrupted inclined path of the paper side of the paper side layer is separated from the adjacent compartment by one paper side layer weft. Alternatively, each compartment in the uninterrupted oblique path of the paper side of the paper side layer is separated from the adjacent compartment by two paper side layer wefts.

Within the paper-side layered pattern, it is preferable that the total section length occupied by each warp of the warp triplet occupying the uninterrupted warp path is the same.

The composite molded fabric of the present invention is generally a single piece because the paths occupied by each warp of the paper side layer warp triple within the fabric tissue pattern are substantially the same and the points where the warp and weave are regularly separated. Woven using an inclined beam.

The paper side layer texture pattern is preferably selected from 2x2, 3x3, 3x6, and 4x8 tissue designs. More preferably, the paper side layer tissue is selected from 2 × 2 plain weave, 3 × 3 tissue, and 4 × 4 tissue. The machine side layer texture pattern is preferably selected from 3x3, 4x4, 4x8, 5x5, 6x6, 6x12 tissue designs. More preferably, the machine side layer tissue is selected from 3 × 3 twill, 6 heald light weave, 9 × 9 twill, or N × 2N tissue as disclosed in US Pat. No. 5,544,678. The tissue design of the machine side layer is most preferably 9 × 9 twill.

The ratio of the number of paper side layer wefts to the number of machine side layer wefts is preferably selected from 1: 1, 2: 1, 3: 2, 5: 3, 3: 1. The ratio is more preferably 2: 1.

Due to the unique structure of the fabric of the invention, it is not possible to limit the ratio of paper side layer slope to machine side layer slope. Only one warp of the warp triples appears in the paper side layer at a time, and only one warp of the warp triples appears in the machine side layer at a time. Thus, the fabrics appear to have a 1: 1 tilt ratio, but this is not meaningful in the concept of these fabrics.

In the fabric of the present invention, the choice of paper-side layer design and machine-side layer design must meet two criteria: firstly, in each cycle of the paper-side layer texture design, each warp of each warp triplet is not interrupted. In the machine side layer, each warp of each warp triplet must be woven at least once alone with the weft in each cycle, in order to occupy sections of the warp path. This is Q / P and Q / M, where Q is the total number of healds, P is the number of healds required to weave the paper-side layer design, and M is the number of healds required to weave the machine-side layer design. It can be achieved by ensuring a quotient that can be expressed. Q, M and P are always integers. For example, if P is 2 and M is 9, since Q is 18, Q / P is 9 and Q / M is 2.

In the simplest embodiment, the fabric of the invention is woven according to a tissue pattern that requires a loom with at least six healds. This requires three pattern cycles to accommodate the plain weave pattern in both the paper side layer and the machine side layer, and to accommodate each of the three slopes of the warp triplet. However, such simple embodiments are generally not preferred because the mechanical side layer wear resistance of the final fabric may not be appropriate for most applications.

In a preferred embodiment of the invention, a 2 × 2 plain weave or 3 × 3 twill is combined with a 6 sheet hemp twill, 6 sheet hemp twill, 9 × 9 twill or N × 2N tissue design for the machine side layer in a paper side layer. Used for The combination of 2 × 2 plain weave and 6 × 6 twill requires 18 healds, 6 × 6 twill requires 18 healds, and 2 × 2 plain weave requires 6 healds, Provides a share of three.

Table 2 summarizes the various possible combinations of paper side layer and machine side layer tissue patterns with heald requirements for each.

TABLE 2

PSL Organization PSL heald, P MSL Organization MSL heald, M Full heald, Q Share Q / P, Q / M 2 × 2 6 6 × 6 18 18 3, 1 2 × 2 6 6 × 12 18 18 3, 1 2 × 2 2 9 × 9 9 18 9, 2 3 × 3 9 6 × 12 18 18 2, 1 3 × 6 9 6 × 12 18 18 2, 1 2 × 2 6 4 × 4 12 12 2, 1 2 × 2 6 4 × 8 12 12 2, 1 3 × 3 9 4 × 4 12 36 4, 3 4 × 8 12 4 × 4 12 12 1, 1 4 × 8 12 4 × 8 12 12 1, 1 4 × 8 12 4 × 8 12 12 1, 1 2 × 2 6 5 × 5 15 30 5, 2 3 × 3 9 5 × 5 15 45 5, 3

In the items of Table 2, "PSL" represents the paper side layer, P represents the number of healds for the paper side layer, "MSL" represents the machine side layer, and M represents the number of healds for the paper side layer. "Whole heald" indicates the minimum number Q of healds required to weave the fabric, Q / P and Q / M are integer values obtained by dividing all healds by the number of healds required for the paper-side layer, respectively, The integer value divided by the heald is divided by the number of healds required for the machine side layer.

Since all warp triples that make up the paper side layer warp are used to weave with the machine side weft, this woven pattern improves the fabric elastic modulus, so that the lateral shrinkage of the fabric and the tendency of the layer delamination Making the fabric more resistant to stretching and warping.

An important difference between the fabrics of the prior art and the fabrics of the present invention lies in the overall warp fill rate given by warp fill rate = (slope diameter x mesh x 100)%. The gradient filling rate can be measured before or after heat setting, and for the same fabrics, the gradient filling rate is generally slightly higher after heat setting. In all prior art composite fabrics, the sum of the warp filling rates in the combined paper side and machine side layers before heat setting is typically less than 95%. Prior to heat fixation, the fabric of the present invention may have an overall warp filling rate which is preferably about 100%. After heat fixation, the fabrics of the present invention may have a total warp filling rate that may be greater than 105%, and typically about 110% or more.

In the context of the present invention, the definition of some terms is important.

The term "unbroken inclined path" refers to the path of inclination in the paper-side layer, which is seen on the paper-side surface of the fabric and occupied by each inclination of the oblique triplet in turn. This path continues along the fabric as the fabric tissue pattern repeats.

The term “segment” refers to the portion of an uninterrupted slope path in a paper-side layer repeating pattern occupied by a particular slope, and the related term “segment length” refers to the length of a particular compartment, within a compartment. One warp of the warp triplet is expressed as the number of weaving paper side layers.

The term "float" refers to the passage of one yarn over other threads without being woven with the other yarns, and the related term "float length" refers to the length of the float, in which one yarn is not woven. Expressed as the number of different threads passing through.

The term "internal float" has a similar meaning and refers to the portion of the yarn that passes between the layers of the composite fabric for a short distance after being woven into the paper-side layer or the machine-side layer. The related term “inner float length” refers to the number of yarns in the paper side or machine side layers, between both ends of the inner float.

The term "interlace" refers to the point at which one warp of the warp triplet wraps around the paper and machine weft yarns to form a single knuckle, and the related term "interweave" , One of the warp triples refers to a trajectory that wraps around one or more paper side weft yarns and forms a bend or float relative to the at least one paper side weft yarn.

Hereinafter, the present invention will be described with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a first embodiment of a molded fabric according to the present invention, showing the path of one slanted triplet in one cycle of the molded fabric tissue pattern.

FIG. 2 is a sectional view similar to FIG. 1 showing a second embodiment. FIG.

In each of the schematic cross-sectional views of FIGS. 1 and 2, within the pattern cycle, the wefts that are cut and shown are numbered starting from 1 in one first paper-side layer weft and ending in the last paper-side layer weft in the other. Is given. Arrows A, B, and C represent the lengths of the paper side layer segments in FIGS. 1 and 2. In addition, in FIG. 1 and FIG. 2, the three inclinations represented by one inclination triplet are represented with code | symbol X, Y, Z. In addition, in FIG. In both composite molded fabrics shown in FIGS. 1 and 2, the same tissue pattern continues along the length of the fabric in the depth direction of the ground in the cross-sectional view shown. This tissue pattern continues in the width direction of the fabric, but is laterally shifted so that the weaving position with the machine side layer weft is not always on the same weft.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross sectional view showing a first embodiment of a forming fabric according to the present invention, taken along a path of a set of warp triples. In Fig. 1, the paper side layer of the fabric is 2 × 2 plain weave, and the machine side layer is 3 × 3 tissue. This organizational representation is because three slopes are shown in FIG. 1, but each slope triplet including the three slopes shown serves as a single slope.

The uninterrupted sloped path in the paper side layer includes the following three compartments. In other words,

The warp Z in the warp triplet is interwoven with weft 1, 3, 4, 6, 7, 9 by passing under weft 3, 6, 9 and above weft 1, 4, 7,

The warp X in the warp triplet is interwoven with weft 10, 12, 13, 15, 16, 18 by passing under weft 12, 15, 18 and above weft 10, 13, 16,

The warp Y in the warp triplet is interwoven with wefts 19, 21, 22, 24, 25, 27 by passing under wefts 21, 24, 27 and above wefts 19, 22, 25.

Within these three compartments there are three machine weaving layers and weaving points. In other words,

-Tilt Z is interwoven with machine side layer weft 20,

-Warp X is interwoven with machine side layer weft 2,

Slope Y is interwoven with machine side weft 11

These three compartments with machine side layer weft and weaving points are repeated for weft yarns 28-54.

The woven fabric of FIG. 1 is woven with 18 healds and can also be woven with 36 healds.

Thus, all three slopes (X, Y, Z) of the warp triple occupy sections of the uninterrupted warp path of the paper side layer (separated by one paper side layer weft), all three slopes It is evident that weave is interwoven with three regularly spaced machine side layer wefts within the length of the three paper side layer slope path sections.

This relatively simple organization also exhibits several other features of the present invention. Looking at the paper-side layer, it can be seen that the slopes X, Y and Z follow the same path, with each slope being displaced along the tissue pattern with respect to the other slopes. It can also be seen that the spacing of the points being woven is constant with two machine side weft yarns between them, but the internal stray lengths of each of the inclinations X, Y and Z at each side of the woven point are not equal.

In section A, it can be seen that warp Z leaves the paper side layer between the weft 7 and the weft 9 and forms an internal float above the machine side layer wefts 11, 14, 17. In the section B, the warp Z is interwoven with the machine side layer weft 20 and forms an internal float on the machine side layer weft 23, 26. In section C, the warp Z reenters the paper side layer between the paper side layer weft 27 and the weft 28, and is interwoven with the paper side layer weft 28, 30, 31, 33, 34, and then the paper side between the weft 34 and the weft 36 Leaving the floor. Then, the pattern in which the warp Z is interwoven with the machine side layer weft 47 is followed. Therefore, the internal floating lengths of the warp yarns Z on both sides of the weft yarns 20 and 47 are not the same. The same applies to the warp yarns X, which are interwoven with wefts 2 and 29, and the same to the warp yarns Y, which are interwoven with weft yarns 11 and 38. Although the difference in internal stray length is small, as shown in FIG. 2, this difference can be avoided and still maintain regular spacing for the points being woven.

In FIG. 2, the paper side layer is 2 × 2 tissue with one weft between subsequent compartments, and the machine side layer is woven into 3 × 3 tissue.

The three inclinations X, Y and Z follow essentially the same path in the paper side layer as described for FIG. 1. In section A, the warp X enters the paper side layer between the paper side layer weft 9 and the weft 10 and weaves with the weft 10, 12, 13, 15, 16, and the paper side layer between the paper side layer weft 16 and the weft 18 Leaves. The warp Y follows the same path as above between the paper side layer weft 18 and the weft 27, and the warp Z follows the same path as above between the paper side layer weft 27 and the weft 36.

In the machine side layer, the points to be woven are regularly separated with two machine side wefts between them, but the weave points are the paper side layer such that the internal floating length of the slope is essentially the same on each side of the point where the warp is woven. It is positioned differently with respect to. The path of the slope Z represents this difference.

In section A, the warp Z leaves the paper side layer between the paper side layer weft yarns 7 and the weft yarn 9, forms internal suspension on the machine side layer weft yarns 8, 11, 14 and is interwoven with the machine side layer weft yarn 17. In section B, the warp Z forms an internal suspension on the machine side layer wefts 20, 23, 26 and reenters the paper side layer between the paper side layer wefts 27 and the weft yarns 28. Thus, it can be seen that the internal flotation in the path of the slope Z is the same length on each side of the point of weaving with the machine side layer wefts 17 and 44. For the other two warp yarns Y, X, warp yarns Y are on both sides of wefts 8 and 35 and warp X is on both sides of wefts 26 and 53 with the same stray length and follow the same path.

This arrangement of points to be woven provides a more uniform location of the drainage openings in the forming fabric and provides a more uniform size to the drainage openings.

Referring to the machine side layer of FIGS. 1 and 2, the interwoven points of each of the warp X, Y, Z are slightly concave from the wear side of the machine side layer of the fabric by the machine side layer weft float exposed at the machine side layer of the fabric. It can be seen that this can potentially increase fabric life. The shorter the exposed weft float length in the machine-side layer tissue pattern, the less weaved points are recessed to a lesser extent. Thus, wear at these locations can be minimized by selecting a machine side layer tissue pattern that provides a long exposed weft float length between the points being woven. Also, although the three slopes of each slope triple occupy sections of the uninterrupted slope path of the paper side surface, the tissue pattern includes any gaps because it continues along the fabric without any interruption in the longitudinal or transverse direction. It can be seen from these figures that no.

Further, by careful selection of the heat setting conditions of the fabric and the yarn material used for warp and weft, it is possible to improve the protection provided at the points being woven. The material of the yarn may be selected to crimp more than the warp triples at the points where the warp triples are relatively harder than the machine side wefts so that the machine side wefts are woven. Heat fixation conditions can be selected to achieve the following two purposes. In other words,

(a) a more rigid warp is placed under tension sufficient to keep the warp relatively straight;

(b) The temperature is selected to facilitate the crimping of the weft against the warp.                 

Representative seal combinations and required heat fix conditions are shown in Table 3.

TABLE 3

slope Machine side layer weft Heat fixed temperature Heat fixing tension PET PET / TPU About 190 ℃ 805 kg / m PEN PET / TPU About 190 ℃ 805 kg / m

Abbreviations for thermoplastic seal materials are those used in Table 1.

Another benefit obtained by using warp yarns of relatively high modulus is that the size of the warp yarns can be reduced. This gives the fabric a low warp fill and high air permeability at the same count.

As discussed above, the tissue structure of the paper side layer should "fit" to the tissue structure of the machine side layer. There are at least three reasons for this.

First, the position where each warp triplet is interwoven with the machine side weft must match the location where one of the different warp triples interweaves with the paper side weft. Thus, the tissue structure of each layer must be defined so that this can occur without causing excessive deformation of the paper-side surface of the paper-side layer.

Secondly, the paper side layer structure and machine side are positioned so that each warp triple is interwoven with the machine side layer weft as far as possible from the ends of the sections of the paper side layer tissue pattern occupied by the other warp of the warp triple. The hierarchical structures should be compatible with each other. This reduces the dimpling and other surface imperfections caused by causing the warp to be woven into the machine side layer from the paper side layer.                 

Third, the location where each warp triplet weaves with the machine side layer weft should be recessed into the machine side layer as much as possible from the wear side of the machine side layer to extend the service life of the fabric. This can be achieved by lengthening the exposed machine side layer weft flotation between two consecutive weaving points as long as possible. The length of the machine side layer weft float increases with the number of healds used to weave the machine side layer tissue pattern. Thus, in general, it is preferred that the machine side layers of the fabric of the invention are woven according to a pattern requiring at least four, preferably at least six, healds.

Experimental test

Four sample fabrics were woven as follows.

Sample fabric A was woven into the tissue of FIG. 1.

Sample fabrics B, C, D were woven into the tissue of FIG.

Details of these four sample fabrics are shown in Table 4.

TABLE 4

Fabric properties Sample A Sample B Sample C Sample D Woven AS PS Mesh 40.2 x 18.9 49.6 x 19.7 49.6 x 20.0 49.6 x 26.8 Woven MS Mesh 40.2 x 11.0 49.6 x 9.8 49.6 x 10.0 49.6 x 13.4 Heat fix PS mesh 45 x 17.3 55 x 18.5 53.5 x 18.1 56.7 x 25.2 Heat fix ms mesh 45 x 8.7 55 x 9.3 53.5 x 9 56.7 x 12.6 Slope diameter 0.25 mm 0.20 mm 0.20 mm 0.20 mm Inclined material PET PEN PEN PEN PS weft diameter 0.26 mm 0.22 mm 0.22 mm 0.22 mm PS weft material PET PET PET PET MS weft diameter 0.45 mm 0.45 mm 0.45 mm 0.30 mm MS weft material PET / TPU PET / PA6 PET / PA6 PET PS organization Plain weave MS organization 1/8 float Heat fixed temperature About 200 ℃ Fabric elastic modulus 2590 kg / cm 1744 kg / cm 2068 kg / cm 1846 kg / cm Fabric thickness 0.019 mm 0.017 mm 0.0165 mm 0.0146 mm MS Weft Crimp -0.0059 0 0 -0.0044 Inclined filling rate in the woven state 100% 100% 100% 100% Inclined filling rate after heat fixation 110% 110% 110% 110% Fiber Support Rate (Beran) 84 Air permeability 7,890 10,300 8,210 8,690

In Table 4,

PS: paper side layer

MS: machine side layer

Mesh: Slope x Weft per cm

PET, PEN, PA6, and PET / TPU: see Table 1

PET / PA6: yarn with alternating PET and PA6

Air permeability: m ³ / m ² / hr; Measured on a heat-set fabric by ASTM D 737-96 with a pressure difference of 127 Pa through the fabric using a high pressure machine sold by Frazier High Precision Instrument Co., Gaitherberg, Massachusetts, USA.

Fabric Elastic Modulus: slope of the stress-strain curve at tension of 3.6 kg / cm to 7.1 kg / cm in CRE type tensile tester

Thickness: Average of at least 5 thickness measurements.

MS weft crimp: The amount by which the knuckle of the machine side layer weft lies above (negative) or below (positive) the side of the machine side layer slope.

Inclined filling rate: (inclined diameter × mesh × 100)%.

Fiber Support: Refers to the amount of support provided by the paper side surface of the paper side layer that is measured according to the relationship provided in CPPA Data Sheet G-18 and that can be used to support the paper fibers in the papermaking material deposited thereon.

In Table 4, although Sample A has a fairly high modulus of elasticity, this fabric has the thickest thickness, at least in part due to the yarn material used therein. The fabrics of Samples A and D exhibited negative MS weft crimps, indicating that in these fabrics good wear life can be expected due to bending out of the long suspension in the machine side layer tissue. This wear life is also enhanced by the use of PET / TPU material on the machine side layer weft.

The choice of appropriate weft and warp diameter for use in the fabric of the present invention depends on many factors, including the grade of the paper product produced by the fabric obtained, and affects the air permeability of the fabric obtained. Selection of the appropriate yarn diameter is made according to the intended end use of the fabric.

Table 4 shows that the fabrics of the present invention have good air permeability of 10,300 to 7,890 m ³ / m ² / hr in the sample fabrics of the data given in Table 4. The air permeability of the fabric can be further reduced by appropriate choice of paper and / or machine side thread diameters and meshes. By reducing the air permeability of the fabric, the fluid drains more slowly through both the paper and machine side layers of the fabric, resulting in improved molding and reduced wire marks. Experimental analysis of hand sheets (hand-drawn sheets) produced on the fabric samples shown in Table 4 confirmed that the wire marks were reduced compared to other conventional fabrics, and the sheets provided improved printing properties. .

Claims (26)

A composite molded fabric having a paper side layer and a machine side layer, (i) a first set of paper side layer wefts, (Ii) a second set of machine side layer wefts coarser than the paper side layer wefts, and (Iii) a set of warp triples contributing to the structure of both the paper side layer and the machine side layer, The three sets of yarns are woven together according to a repeating pattern, (a) each warp of each warp triplet is woven with the paper side layer weft so as to occupy sections of a single uninterrupted warp path of the paper side layer, (b) the order of the compartments is repeated as part of a repeating pattern, (c) each compartment of the uninterrupted inclined path is separated from the next compartment by at least one paper side layer weft, (d) each warp of each warp triplet is individually woven with a single machine side weft yarn at least once within the pattern cycle, (e) Within the fabric repeat pattern, the number of machine side layer wefts between the points at which successive warps from each warp triplet are respectively woven is constant, (f) Within the fabric repeating pattern, the composite molded fabric characterized in that the path length of each warp of each warp triplet is the same. The composite fabric of claim 1, wherein the fabric as it is woven and prior to heat set treatment has a warp fill of 100% to 125%. 2. The composite fabric of claim 1 wherein the warp and weft yarns are thermoplastic monofilaments. 4. The composite molded fabric of claim 3, wherein the first set of paper side layers and the second set of machine side layer wefts and the warp yarns are monofilaments of the same thermoplastic material. 5. The composite molded fabric of claim 4, wherein the first set of paper side layers and the second set of machine side layer wefts and the warp yarn are both polyethylene terephthalate monofilaments. 4. The composite molded fabric of claim 3, wherein the warp yarn is made of a thermoplastic material that is different from the material of at least one set of the weft yarns of the first set of paper side layers and the second set of machine side layer wefts. 4. The method of claim 3, wherein the first set of paper-side layer weft yarns comprises at least first and second subsets of weft yarns, each weft yarn being a monofilament of a different thermoplastic material. Composite molded fabric. 4. A composite molding according to claim 3, wherein said second set of machine-side layer weft yarns comprise at least third and fourth subsets of weft yarns, each weft yarn being a monofilament of a different thermoplastic material. textile. 2. The composite fabric of claim 1 wherein the warp yarn is a thermoplastic monofilament having a higher modulus of elasticity than the thermoplastic monofilament of the machine side layer weft. The composite molded fabric according to claim 9, wherein the ratio of the elastic modulus of the warp yarn and the elastic modulus of the weft side layer yarn is 4: 3. 2. The composite molded fabric of claim 1, wherein in each of said first set of paper-side layer wefts, said second set of machine-side layer wefts, and said warp yarns, they are all the same size. 4. The composite fabric of claim 3 wherein the first set of paper side layer weft yarns and the second set of machine side layer weft yarns are polyethylene terephthalate monofilaments. 2. The method of claim 1 wherein the second set of machine side layer wefts is selected from the group consisting of polyethylene terephthalate monofilament, monofilaments of a mixture of polyethylene terephthalate and thermoplastic polyurethane, polyamide monofilaments, and mixtures thereof Composite molded fabric, characterized in that the yarn. 14. The method of claim 13, wherein in the second set of machine side layer weft yarns, the third subset of weft yarns consists of a monofilament of a mixture of polyethylene terephthalate and thermoplastic polyurethane, and the fourth subset of weft yarns is polyethylene tere A composite selected from the group consisting of phthalate monofilaments, polyamide monofilaments, and mixtures thereof, wherein the wefts of the third subset comprise at least 50% of the weft side layer wefts of the second set textile. 4. The composite molded fabric of claim 3, wherein said warp yarn is selected from the group consisting of polyethylene terephthalate monofilament, polyethylene naphthalate monofilament, and mixtures thereof. 15. A composite molded fabric according to claim 13 or 14, wherein said polyamide monofilament is selected from the group consisting of polyamide-6 and polyamide-6 / 6 monofilaments. The air permeability of claim 1, wherein the fabric ranges from 3,500 m ³ / m ² / hr to less than 10,500 m ³ / m ² / hr at a pressure difference of 127 Pa through the fabric as measured by standard test procedures. Composite molded fabric characterized in that it has a. The composite molded fabric of claim 1, wherein the tissue design of the paper side layer is selected from the group consisting of 2 × 2, 3 × 3, 3 × 6, and 4 × 8 tissues. 19. The composite molded fabric of claim 18, wherein the tissue design of the paper side layer is selected from the group consisting of 2x2 plain weave, 3x3 tissue, and 4x4 tissue. The composite molding according to claim 1, wherein the tissue design of the machine side layer is selected from the group consisting of 3 × 3, 4 × 4, 4 × 8, 5 × 5, 6 × 6, 6 × 12 tissues. textile. 21. The tissue design of claim 20 wherein the tissue design of the machine side layer is selected from 3 × 3 twill, 6 heald light twill, or N × 2N tissue, where N is an integer and is the number of healds in the loom. Composite molded fabric characterized in that. The composite molded fabric of claim 1, wherein the ratio of the paper side weft yarn to the machine side weft yarn is selected from 1: 1, 2: 1, 3: 2, 5: 3, 3: 1. 23. The composite molded fabric of claim 22, wherein the ratio of said paper side weft yarn to said machine side weft yarn is 2: 1. The method of claim 1, wherein when Q is the total number of healds, P is the number of healds required to weave the paper-side layered tissue, and M is the number of healds required to weave the machine-side layered tissue. A composite molded fabric characterized in that the quotient expressed by Q / M is an integer. 4. The yarn of claim 3 wherein the warp is polyethylene naphthalate, the first set of paper side layer wefts is polyethylene terephthalate, and in the second set of machine side layer wefts, a third subset of weft yarns is polyethylene terephthalate. And a monofilament of a mixture of thermoplastic polyurethane and a thermoplastic yarn, wherein the weft yarn of the fourth subset consists of polyamide monofilament. 4. The yarn of claim 3 wherein the warp is polyethylene terephthalate, the first set of paper side layer wefts is polyethylene terephthalate, and in the second set of machine side layer wefts, a third subset of weft yarns is polyethylene terephthalate And a monofilament of a mixture of thermoplastic polyurethane and a thermoplastic yarn, wherein the weft yarn of the fourth subset consists of polyamide monofilament.

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