JPH0280688A - Molded cloth for papermaking industry and method for molding the same - Google Patents

Abstract

PURPOSE: To obtain a paper maker's forming fabric improved in abrasion resistance and reduced in dimensional instability by using a blend of a polyester and a thermoplastic polyurethane. CONSTITUTION: This paper machine forming fabric comprises (a) at least one pair of yarns woven in a first-order direction of the fabric and (b) at least one pair of yarns that are woven in a second-order direction of the fabric, and is formed of a blend comprising 60 to 90 wt.% of a polyethylene terephthalate and 40 to 10 wt.% of a thermoplastic polyurethane and contains 0 to about 5 wt.% of a hydrolysis stabilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a molded fabric for the paper industry made from synthetic plastic fibers.

[Conventional technology]

Paper machines form continuous sheets of paper or paper stock by forcing a water-based slurry of cellulose fibers onto a constantly conveying woven belt. As the slurry is continuously moved through a belt, also known as forming cloth or forming wire, it transforms into a nearly self-supporting wet paper by wicking away much of the moisture contained in the initial slurry. A typical slurry delivered to a moving forming fabric can include as much as 0.5% by weight of cellulose fibers, and the temperature can range from about 30°C to 85°C;
Moreover, the standard pH is between 4 and 9. The wet paper on which the formed fabric is subjected to pressing and drying sections can contain 80% water by weight.

If the paper remains damp, it will pass through the wet end or
After passing through the forming section on the couch roll, it is sent to the press section. Here, most of the residual moisture is removed by passing through a series of pressure dowels.

On passing the press section, the paper web passes through a heated drying section for final drying. Next, the dried paper web is polished to make the surface smooth and finally wound on a reel.

As the wet slurry moves along the forming fabric, water removal is facilitated by the use of hydrofoils, table rolls, and suction boxes.

The forming fabrics in the original Fourdlinière paper machines were constructed from woven metal wires, and as a result these fabrics became known as Fourdrinier wire. These fourdrinier wires are also used in all types of paper making machines and all paper types. While effective, these wires are not without drawbacks, especially when the cellulose fiber slurry contains abrasive fillers such as silica and calcium carbonate. It is.

Recently, these wire woven fabrics have been replaced by woven fabrics made from synthetic plastic fibers, commonly monofilaments. The structure and properties of the formed fabric are particularly important because the final substrate of high-quality paper is formed from the fabric. The main advantage of synthetic plastic monofilament woven fabrics on phosphor bronze wire is improved abrasion resistance with an average lifespan of more than four times that of wire woven fabrics.

However, these woven fabrics still have a tendency to abrade with the same type of filler causing problems with aging phosphor bronze wire. In order to successfully combine paper machine forming fabrics, it is desirable to have the following characteristics:

(i) It is also abrasion resistant by frictional contact with mechanical parts and by contact with solids in the cellulose fiber-water slurry.

(ii) The structure of the woven fabric surface is stable and can withstand stress applied during use.

(i i i) The machine is completely wet during operation;
Moreover, since it dries when the machine is stopped for a long period of time, the woven fabric surface does not undergo any dimensional changes even if moisture is absorbed by moisture-absorbing components over a wide range.

(iv) It is resistant to tensile force even when subjected to the tensile force applied by the power rollers that send out the woven fabric during papermaking.

(V) Not to be denatured by various substances present in the cellulose fiber water slurry and the materials used for cleaning molded fabrics at typical operating temperatures.

Even existing woven fabrics and long-term phosphor bronze fourdrinier papermaking wires have not completely destroyed all these properties.

For example, as explained above, phosphorous copper wire does not have a certain wear resistance. Even commercially available synthetic plastic monofilaments do not meet all the standards required by the paper industry.The synthetic polymers that are acceptable monofilaments, such as those currently used in the production of molded fabrics, are polyesters. is polyethylene terephthalate, and polyamide, more specifically nylon.
6 (polycaprolactam) and nylon-66 (polyhexamethylene adipic acid). These monofilaments have been mixed with other monofilaments such as polyethylene and polyester based on polybutylene terephthalate, but previously these woven fabrics have been far from inert. In fact, there are two essential differences:

(a) While polyethylene terephthalate has more than sufficient chemical stability and dimensional stability, is easy to weave, has good crimp properties, and exhibits good heat cent behavior, it has particularly poor abrasion resistance. Modern high-speed machines have many drawbacks.

(b) Although nylon-6 and nylon-66 have sufficient abrasion resistance, they have very poor crimp properties and insufficient heat-setting behavior, which is a serious drawback for fiber making, and they are not suitable for papermaking environments. Dimensional stability is poor in the temperature range of
Moreover, they are not sufficiently resistant to some of the substances used to clean molding fabrics.

The inherent dimensional instability of nylon-6 and nylon-66 in humidity ranges such as operating papermaking environments from fully wet to dry limits the ratio of nylon monofilament to polyethylene terephthalate monofilament.

This is reflected in U.S. Patents 4.529.013 and 4.28.
9.173.

West Germany O8 2.502.466 gives a similar figure of 50%, further suggesting that nylon filaments should be at least 4% larger in diameter (with a recommended maximum of 25%) than polyester monofilaments. There is. For example, European publication application 158.710
Attempts to solve these questions by improving the abrasion resistance of polyester monofilaments while maintaining superior dimensional stability compared to nylon have not yet been completely successful, as shown in . Similarly, Canadian Patent, 2
Even if the abrasion resistance of nylon monofilaments is improved as disclosed in 35.249, it does nothing to reduce the dimensional instability of existing nylons, thus solving the limitations of nylon monofilament content. I can't. An alternative solution to the need for nylon crimpability is proposed in US Pat. No. 4,709,732. However, here, the symmetrical consideration is the increase in complexity of the woven fabric, not the dimensional instability, and no increase in the nylon content is allowed.

Thus, for molded fabrics containing nylon and polyester, an acceptable compromise can be made by limiting the amount of nylon used. The woven fabrics appear to be resistant to the expected pH during use and may range from about 4 to 8 or 9. Polyester fibers do not degrade appreciably under these conditions, even in the temperature range up to about 85° C. found in modern paper machines.

[Purpose of the invention]

The present invention also refers to papermaking fabrics which are directly connected to the wet end or forming section of a paper machine and are also known as "forming fabrics." These fabrics are used to remove moisture from cellulose fibers to form a wet paper web during the initial stage of water removal.

The present invention also seeks to solve problems associated with the use of nylon by using alternative forming fabrics for the paper industry, including monofilaments based on polymer blends with the weaving and heat-setting properties of polyethylene terephthalate. be. Regarding this woven fabric, we will also discuss at least the abrasion resistance of ordinary nylon-containing woven fabrics. Regarding the remaining material of the formed fabric, it is desirable to use polyethylene terephthalate monofilament, but since other threads or monofilaments may naturally be used, the present invention strictly adheres to the use of this polymer in the remaining woven fabric. It's not a thing. Further, in the following description, the present invention will be discussed by regarding monofilaments as woven fabrics, but this is not strictly adhered to, and the present invention can also be used for formed fabrics woven from yarns and monofilaments. The yarn used is preferably a monofilament.

〔Example〕

Accordingly, in its broadest aspects, the present invention provides a paper machine forming fabric woven from:

(a) at least one set of yarns woven in the primary direction of the woven fabric; (b) at least one set of yarns woven in the secondary direction of the woven fabric, essentially perpendicular to the primary direction, essentially 60x4; % or more to 90% by weight of polyethylene terephthalate and 40% by weight
% to io weight percent thermoplastic polyurethane, and the blend includes O to about 5% hydrolysis stabilizer.

For the present fabric in a preferred embodiment, the yarns used in the -next and secondary directions are monofilaments, and the yarns used in the -next direction, along with the remaining secondary direction yarns, are preferably polyethylene terephthalate.

Thus, the use of the novel monofilaments of the present invention in its broadest embodiment is independent of the form of the woven fabric used. This includes woven fabrics commonly known as single layer, two layer or double sided, and composite. Additional descriptions of these common forming fabric types can be found in U.S. Pat.

For more specific embodiments, the present invention essentially comprises six
Synthetic monofilament made from a blend of 0% to 90% by weight of polyethylene terephthalate, 40% by weight to 10% by weight of thermoplastic polyurethane, and about 5% by weight of a hydrolysis stabilizer for thermoplastic polyurethane. Also provided.

Preferably, the weight percent of thermoplastic polyurethane is about 15%.
or more, more preferably 25% to about 35%, and most preferably the amount of thermoplastic polyurethane is about 3
It is 0%.

In a further broader embodiment, some of the threads forming the formed fabric surface to which the cellulose fiber pulp slurry is applied are monofilaments of a blend of thermoplastic polyurethane and polyethylene terephthalate as defined above;
Moreover, where the majority of the machine side of the formed fabric is a monofilament blend of thermoplastic polyurethane and polyethylene terephthalate as defined above, the present invention provides a formed fabric that can be used by a papermaking machine.

For a preferred embodiment of the professional fabric, the yarn used is a monofilament. In a further preferred embodiment, the threads that make up most of the surface of the formed fabric and part of the machine side of the woven fabric are monofilaments of polyethylene terephthalate.

From what follows, the term "machine direction" means essentially parallel to the direction of flow of the forming fabric through the paper machine. Similarly, the term "machine cross-sectional direction" means a direction in the plane of the fabric that is essentially perpendicular to the "machine direction." Not as a continuous loop, but rather as a regular length of woven fabric (
For formed fabrics woven as (later joined to form continuous loops) "machine direction" corresponds to the warp threads and "machine direction" corresponds to the weft threads.

Thus, the woven fabric of the present invention consists of two types of yarn, preferably one of which is a polyester monofilament;
Another yarn is a monofilament blend of polyester and thermoplastic polyurethane.

To my complete surprise, polyurethane from 10% to almost 4%
It has been found that blends containing 0% provide abrasion resistance similar to nylon monofilament, but without the problems associated with such nylons caused by permanent crimp loss. In fact, certain polyester-thermoplastic polyurethane blends exhibit better crimp and heat-setting behavior in monofilaments than thermoplastic polyurethanes. This property is directly related to the weaving behavior of these monofilaments and is generally unpredictable. The use of monofilaments made from kosha blends further simplifies the weaving configuration by eliminating the use of nylon monofilaments, which are often used in the cross-sectional direction of the machine (to provide sufficient abrasion resistance to the machine side of the tomoori 41). At best, substitute yarns can be mixed into the weaving to suppress the well-known dimensional instability of nylon due to the presence of water.Therefore, in the monofilament of the present invention, the monofilament with a polyester-thermoplastic polyurethane blend is There is no need to mix the weft threads as it can be used alone as the only weft thread. This means that the polyester-thermoplastic polyurethane blend monofila, Mento, only needs to be used as the weft thread of the woven fabric on the machine side. In composite N woven fabrics, this monofilament is of particular interest since it represents a highly abrasive surface.

Blended monofilaments not only provide material that can be melt-injected into suitable monofilaments;
In order to provide a polymer blend with sufficient properties, there are several requirements that the polyester component must meet. In addition to the standard conditions such as the absence of water content (at most 0.07%), the polyester molecule must be the same as the resin normally used for the warp and weft threads.Therefore, for the polymer: When measured according to the method described in Section R, it must have an intrinsic viscosity in the range of 0.50 to 20.The range of intrinsic viscosity is preferably 0.65 to 0.5. Grades of polyethylene terephthalate available under the names (also trademarked R) possess these properties.

DuPont rMerge 1934J (Dubon product sold under this name) Alunite AO6-300 (trademark of Akzo) Vitaf
9504C (Gutsdoyer trademark) Tenite 1038
8 (Eastman Trademark) As a guide, these preferred viscosities correspond to number average molecular weights ranging from approximately 5 x 104 to 5.2 x lO'.

The intrinsic viscosities discussed below are phenol and (1°, 2.
2) Measurements were made using a solution in which polyester was dissolved in a solvent containing tetrachloroethane mixed at a weight mixing ratio of 60:40. Viscosity measurements are carried out at 30°C.

When looking at the thermal stability of the blend and the proportion of polyurethane, in order to descend into monofilament by the usual melt injection method, the material used must be woody anhydrous, as free from impurities as possible, and also free from "stains". It is necessary that there be no. Generally, there are two types of thermoplastic polyurethanes. That is. There are polyester derivatives and polyether derivatives. For purposes of this invention, polyester variants have been found to be preferred as they are more effective.

Preferably, the thermoplastic polyurethane is a relatively soft material and softness is measured according to the standard method described in Method A37M, No. 2240. Regarding hardness, A
Shall not exceed 95 when measured with a Type D durometer or 75 when measured with a Type D durometer.

The thermoplastic polyurethane grades available under the following names (trademarks) are the polymer monofilament 1 of the present invention:
- Suitable for producing blends of

Ester-based types: Texin 445D (Trademark of Mobay) Elastran C95 (Trademark of BFSF) Berethane 210
2-80AE (Trademark of Dow Chemical) Ether-based types: Texin 990A (Trademark of Mobay) Pellethane 2102-80A (Trademark of Dow Chemical) In the previous explanation, the percentages are 100% mainly because of the hour wheel.
And so. Generally speaking, other additions are only in small amounts, with pigments such as TiO2 adding up to 0.5% by weight to give the fiber the desired appearance. Under certain conditions it is necessary to add hydrolysis stabilizers. The paper machine is about 43 to 4
Hydrolysis of the blended monofilament in the present invention does not need to be emphasized as long as it is operated at a temperature below 8°C. Many paper machines operate at temperatures even higher than this, 85°C. This is necessary because at temperatures of this order, blended fibers appear to degrade more rapidly than expected without hydrolysis stabilizers.

It appears that it is the thermoplastic polyurethane that decomposes as shown below, since tests have shown that the tensile strength is only marginally affected, but the abrasion resistance is significantly reduced.

The amount of stabilizer used can be from zero up to about 5% of the total weight, beyond which no further improvement is observed. When a stabilizer is used, no prevention rate is observed at about 0.3% or less. Therefore, about 0.3% to 5.0
It is desirable to use stabilizers within the range of %, with a more preferred range of about 0.3% to about 3%. The stabilizer is conveniently incorporated into the blend by a "master patch" made of either thermoplastic polyurethane or polyester.

Available stabilizers of the latter type that have been found to be effective include:

Stavaxol KE7646 (Trademark of Reign Chemie) Stavaxol Ploo (Trademark of Reign Chemie) Hytrel IOMC (Trademark of DuPont) Monofilament can be mixed with antistatic and anti-friction agents for ease of handling and weaving. It is conceivable that a surface coating may also be applied. Gradual coatings are generally removed as soon as the woven fabric is used in a paper machine.

example To summarize, the following abbreviations are used in the following examples:

PET is used to refer to polyethylene terephthalate, and TPU is used to refer to thermoplastic polyurethane. Where appropriate, TPU stands for ether-based or ester-based.

In the following example, PET is a DuPont product sold under the name Merge 1934J.

Generally, the material is dried before use and can be post-condensed in solid form to bring the intrinsic viscosity within a specified range. Similarly, the material TPU is in a dry state before use. Nylon is always nylon.

These examples also use monofilaments made from special polymers. Where relevant you will find the dimensions of these monofilaments.

Generally, the monofilament used in forming cloth is about 0゜l a
The size ranges from m to about 0.9 mm, and the commonly used size ranges from about 0.127 mm to about 0.4 fl. The cross section of monofilament does not have to be circular;
It should be noted in particular that it can also be fitted in a square or ribbon shape.

A. To determine the abrasion resistance of monofilament, first weigh a strand of monofilament and then wrap it around one end of a polyethylene rod. Wrap the polyester contrast monofilament around the other end. Next, a rod is attached below the chamber axis perpendicular to this, and the two rolls are immersed in a slurry containing 57% by weight of sand with a grain size of No. 24 in water. The shaft is rotated by a motor-driven mechanism installed above the tank containing the slurry. After a set time, the strands are removed from the slurry, rewound, dried, and weighed.

Abrasion resistance is determined by calculating the percent weight loss. To obtain measurement results, select the time and rotation speed of the axis. Regarding the abrasion resistance of degraded specimens, the pH was adjusted to vary the time.
and after immersing a monofilament coil in a temperature-controlled solution, it is determined by similar means.

The following results were obtained with PET-TPU blends with varying concentrations of TPU.

Example Composition Weight Loss %Al
10-0% PET control 3.2A295%P
ET+5%TPU 3.4A385%PET+l
5% TPU3. IA475%PET+25%TPU2
．． 4A565%PET+35%'rpui, aA655
%PET + 45% TPU, 1 From this data, the abrasion resistance of monofilament made from a blend of PET and TPU is PE with 15% TPU.
It was slightly better than T and improved as the concentration of TPU increased up to 45%. However, monofilaments at this concentration are difficult to control during injection and become extremely soft, making them unsuitable for weaving and heat setting.

The TPU used in these experiments is Texin 445D.

The effect of the stabilizer on the pH 4.0 solution in improving the decomposition resistance of the blended monofilaments is shown in the following results.

Example Composition A7 64%PET+36%TPU A8 64%PET+36%TPU A9 64%PET+36%TPU AIO62%PET+37%TPU +1% stabilizer All 62%PET+37%TPU+1% stabilizer Al1 62%PET+37%TPU+1% stabilizer example exposure loss Weight% A7
21 days 71'C2,3 A8 7 days 88℃ 2,3A9
100℃ for 3 days 2.7AI0 21 days 71
”CI, 2 A11 88℃ for 7 days, 2A12
100° C. for 3 days, 4 From this data, the addition of stabilizer to the PET-TPU blend resulted in a significant improvement in decomposition resistance at all temperatures. The stabilizer in these cases is Stabaxol KE 76
46, and the TPU was Chixin 445D.

The effect of stabilizer concentration is shown in the following table.

Example Composition Al1 66% PET + 34% TPU AI4 73.2% PET + 26% TPU + 0.8% Stabilizer A15 7, 8% PET + 26% TPU + 2.2% Stabilizer Example Exposure Weight Loss % A13 3
100℃ for 1 day 2.5AI4 100℃ for 3 days
, 9 A15 at 100° C. for 3 days, 9 Both stabilized blends significantly improved the decomposition resistance, but no further improvement was observed with higher concentrations of stabilizer.

In these examples, the TPU was PERETANN80AE and the stabilizer was Staboxil KE 7646.

Another test showed that the stabilizer was 65% PET and about 35% T P
The effect on the abrasion properties of blends in which tJ was not hydrolyzed was investigated. The results are shown in the table below.

Example Breakdown of strand 1 member weight loss%A1
9 Polyester 2.2A20
64%PET+36%TPU I, 2A20 6
4% PET + 36% TPU, 1 + 1% stabilizer This data shows that the addition of stabilizer does not adversely affect wear resistance. In this experiment, T
The PU was Texin 445D and the stabilizer was Staboxil KE7646.

The polyester used in all experiments from A1 to A19 was DuPont Marge 1934, which was post-condensed in solid form.

B. Abrasion molding of woven fabrics To determine the abrasion resistance of fabrics, woven fabric specimens were fixed facing the external surface of a drum made of ceramic segments rotating in a horizontal plane under tension. . Keep the woven cloth and ceramic surface wet by constantly applying water to the woven fabric in the drum.

The thickness of the fabric is measured at the beginning of the test and at specified times thereafter against the rotating ceramic segment surface. The thickness lost is the measure of wear resistance.

Using warp yarns with a diameter of 0.16n+, the number of meshes is 59/
One double-woven fabric marker was woven as cm.

PET for lower side or machine side set of weft, substitutes P
Blends of ET/nylon and 75% PET/25% PTU were used to weave. The number of weft threads is 51 each.
/cm.

All of these specimens were woven using a 0.19 mm diameter root side weft and a 0.30 mm diameter machine side weft.

The results of the abrasion test where the machine side of the fabric was in contact with the drum are shown in the following table.

1111 Loss thickness (related) - Example Time B3 105 Example Substitute PET/Nylon-66 PET target 2I0 75% PET/25% TPU blend 83, 0162 From this result, it is found that the substitute PET/Nylon weft made from Woven fabric and 75%
It can be seen that the woven fabric made of a PET/25% TPU blend weft has better abrasion resistance than the woven fabric woven with a PET weft.

Furthermore, woven fabrics using PET/TPU wefts can be substituted with PE.
It has better abrasion resistance than woven fabrics using T/nylon.

In the second test, the abrasion resistance of woven fabric specimens using blended heptofilaments with varying concentrations of PET and TPU was measured.

The upper mesh number was 25/cra and the lower mesh number was 12.5/cm. The upper and lower wefts of the rectangular cross section each have a diameter of 0.11 mm to 0.1 mm.
There were 19 ■ and 0.19 ■■ to 0.38 dragon. In all cases, 0.14 m PET weft binder or tie strands were used. The lower layer of woven fabric was in contact with the drum.

Example Composition Thickness after 75 minutes (Dragon) B4
100% PET control, 018B584%
PET+16%TPU, 015B675%PET
+25%TPU, 013B765%PET+35
%TPU, 011B5 Substitute PET/Nylon-
66,012 The TPO used was Texin 445D, and the PET was DuPont Merge 1934, and the post-condensation was performed while they were solid.

This data includes findings from strand abrasion tests;
That is, the abrasion resistance of fabrics woven with blended PET/TPU wefts is better than that of fabrics woven with 100% polyester wefts, and the abrasion resistance increases with increasing polyurethane concentration. This supports the findings. Substitute PET for 65% PET/35% TPU specimens
/Nylon-66 specimen has better abrasion resistance.

C0 Dimensional Stability by Wet and Dry Molded fabrics are often subjected to drying and wetting processes. For example, it is sent to a paper mill, dried, and then saturated with water immediately after the paper making operation of the paper machine. During this life, the molded fabric may dry out many times due to maintenance shutdowns or weekends. For forming fabrics with a high percentage of nylon monofilament in the cross-sectional direction of the machine,
Changes in width. When polyester and nylon monofilament are contained in two layers, there is a difference in the degree of expansion and contraction between the two layers, which causes the fabric to bend at the edges. This behavior limits the use of nylon monofilament to 50% of the fibers in the total machine cross-section direction. Most molded fabrics are limited to 25% of the total. That is, 50% of the monofilaments in the machine cross-sectional direction on the machine side are made of nylon, and the remaining fibers on the machine side and the monofilaments on the Gisu line are all PET.

For polyester monofilaments, when the nylon content is 25%, the nylon monofilaments and all woven fabrics exhibit significant stretch resistance at varying water contents.

Length measurements were performed at room temperature immediately after wetting or drying.

Example I I PU PET Change in length from dry to wet (%) 0.74 0.07 0°07 0.10 0.03 0.0? -0,43 Monofilament composition 10% nylon -66 10% PET 95% PET 15% TPU 85% PET/15% TPU 75% PET/25% TPU 65% PET/35% TPU 55% PET/45% TPU From wet Change in length due to drying (%) +0.64 +0.07 +0.04 +0.10 +0.03 +0.04 10, 23: Texin 445D: DuPont [Merge 1934J, intrinsic viscosity, made of concentrated nylon and polyester to 02 The results show that there is a well-known behavior with monofilaments. It also shows that the monofilaments made from the blends of the present invention are very stable. Blend monofilaments begin to show dimensional instability at 45% T P U t'f4 degrees.

D. Crimp The commonly used measurement of crimp for weft strands of formed fabrics is commonly referred to as differential crimp. The monofilaments of the warp yarns in the final woven fabric tend to be straighter than the weft yarns, which are slightly more easily bent above and below the warp yarns.

Therefore, weft monofilaments tend to be superior to warp monofilaments, especially on the machine side of woven fabrics. However, if the weft is a very stiff monofilament, it tends to bend the warp, so it is not much better than the warp. By carefully measuring the thickness of the fabric, it is possible to determine how far the weft threads extend beyond the plane of the warp threads. This difference in the warp and weft planes is called differential crimp. The higher the weft monofilament crimp, the higher the differential crimp for any given woven structure.

Examples of differential crimp seen in specimens of double woven fabrics with the same weave construction, warp strands, mesoche number, and heat setting history in various weft strands are shown in the following table.

Example Weft differential crimp (ms)
Dlo, 30 cranes' PET, 014D20
．． 30 dragon nylon, 0,3 substituted for 012
0 Dragon's PET D30.30 Iris m75 % PET/
It can be seen that the crimpability of the blended PET-TPU monofilament of 01725% TPU is much higher than that of polyester, while the crimpability of nylon is lower. The blend of PET and TPU is the same as Example E5 below.

E0 Mechanical Stability The mechanical stability of the formed fabric is evaluated by measuring its resistance to elongation and thinning.

Attach a fabric 25.411 in length and 50 in width to an Intron™ tensile tester. The tensile force of the specimen is from zero to 7.1
Load and extension are recorded while increasing to 6 kg/Cff1. Tension resistance is determined by measuring the slope of the load-elongation curve. This defines the elastic modulus of the fabric, which ranges from about 1100 to about 2000 kg/c for molded fabrics.
It is in the range of m.

As for the reduction in grain resistance, the specimen tensile force is from zero to 7.16.
Measurements are made on the same specimen mounted on the Instron, except to accurately measure the decrease in width when increasing to kg/cm. The durability reduction factor can be found by dividing the measured width change value by the total tensile increase value to obtain a percentage value. The standard reduction factor of molded fabric is 0.005%/kg/c
m to 0.050%/kg/cs.

These high elastic modulus and low wear resistance coefficient reflect optimal mechanical stability.

In order to study the influence on the mechanical stability of the weft yarns, hand-woven/plain-woven fabrics were prepared using warp yarns with a rectangular cross section of 0.11 to 0.19 mm, and the yarns were added at the top of the woven fabric with 25/Cl11
Three pieces were woven, one with a threaded one, and one with warp yarns with a rectangular cross section of 0.19 to 0.38 mm. Three types of lower weft yarns were woven with the same number of meshes, and the resulting specimens were heat set under the same conditions. The elastic modulus and grain reduction coefficient of the three types of specimens are shown in the table below. The data for specimens El and E2 show that nylon has an unfavorable effect on the elastic modulus and the tear resistance factor of the woven fabric.

Example Breakdown Heat set tensile force kg
/ cm Elo, 3 squares ■PET warp 5.37E20.3■
1 Substitute PET 5.37 and Nylon-66 Warp E30.3m Substitute PET 6.26 and Nylon-66 Warp example Elastic modulus Resistance reduction factor kg/c
m kg / craEl 1238
0.015E2 1091 0.03
5 E3 1292 0.032 This behavior of nylon can be partially overcome by using high heat set tensile forces to force the nylon to a high level of permanent crimp, as shown in Example E3. Note that tensile resistance is improved using heat-set tensile forces, but the reduction factor is not affected accordingly. Monofilaments made from blends of PET and TPU also exhibit inherent crimp, improving mechanical stability. This is true for woven fabric specimens using 75% PET/25% TPU warp yarns, which were woven and heat set in the same way as the specimens described above, and for specimen E, which contains only PET warp yarns.
This can be understood from the data in the following table, which is compared with l.

Example Heat set tensile force Elastic modulus kg/ct
s kg/cmEl 5.37
1238E5 5.37
1408 cases Eye reduction factor kg/ctm El O, 015 E5 0.012 PET was DuPont Merge 1934, which was subjected to post-condensation in solid form, and TPO was Texin 445D.

F. Chemical Resistance In papermaking environments, formed fabrics can often undergo periodic cleaning with harsh acidic conditions. Washing with such strong acids will adversely affect the nylon monofilaments in the formed fabric, thus impairing the life of the fabric and the abrasion resistance promotion provided by the presence of nylon in the fabric. Nylon, polyester, and PET/T
Tests were conducted in which coils of various blends of PU were immersed in 30% hydrochloric acid at 25°C for various times. 17
After an hour, the nylon completely dissolved, but the polyester and PET/TPO blend was found to be adversely affected after 222 hours. This indicates that PET/TPU blends are much more resistant to harsh acid cleaning solutions than nylon.

G. Polyester Molecular Weight To determine whether the molecular weight of the polyester used in the blend has any relationship to the abrasion resistance of the monofilament, the molecular weight of the polyester was varied as measured from the intrinsic viscosity (1, V). Blends of the two monofilaments were injected under conditions of the same polyurethane concentration.

Next, the abrasion resistance of the monofilament was measured using a sand slurry test, and the results are shown in the following table.

Example: Breakdown of strands, V.

Gl 100% PET control, 02G2
100% PET control 0.65G375%P
ET; 25% TPU, 02*G4 75% PET
;25%TPU O, 65*Example Weight loss % G12.8 G23. l G3,9 G42.1 *This is for polyester used alone, not for blends.

From these numbers, when blended using TPU, P
It can be seen that when the molecular weight of ET is high, the fiber has slightly better abrasion resistance than PET with a low molecular weight. Both fibers have significantly improved abrasion resistance over the PET control monofilament. In this way, the molecular weight of PET is
- It does not seem to be a significant factor influencing the abrasion resistance of TPU blend monofilaments.

H, Comparison of ether-based and ester-based TPUs From the viewpoint of abrasion resistance, in order to clarify whether ester-based TPUs are more advantageous than ether-based TPUs, the same molecular weight products with an intrinsic viscosity of 02 PET
A series of blends were injected under the same conditions using

Next, the abrasion resistance of the monofilament was measured using a sand slurry test. The results are shown in the table below.

Example Monofilament composition Hl 100% PET control H2 80% PET + 20% ether base TPU H37
0% PET + 30% ether base TPUH480%P
ET+20% ester base TPUH570% PET+
30% ester hese TPU example Weight loss % Old 3.2 822.7 H32.4 H42.5 H52.0 This data is a certain TPtJ? At 1 degree, ester-based TPUs show better abrasion resistance than ether-based TPUs. The ether-based TPU used was Dexine 445D;
PU was Texin 990A. PET is DuPont
Merge 1934, and post-condensation was carried out while it was solid.

(2) Injection of monofilament To create a monofilament made of a blend of polyester and polyurethane, the polyester and polyurethane resin beads were first dried, then mechanically kneaded and filled into an injection hopper to be sent to a single-screw extruder.

If a stabilizing agent is used, a predetermined amount of the stabilizing agent may be conveniently added as a concentrate to either the masterbatch or the polyester-polyurethane. The amount of polyester or polyurethane added along with the stabilizer is taken into account when determining the amounts of the components. Melting and kneading of the resin mixture takes place while a screw conveys the molten mixture at about 275° C. through a heated cylindrical cylinder. The injection temperature may range from 260°C to 285°C, and may range from 265°C to 285°C.
A range of 75°C is preferred.

After the monofilament is released, it is rapidly cooled in a water bath to form a solid fiber. These have a stretching ratio of 3
．． Stretching is carried out by raising the temperature to 100° C. between a set of stretching rollers with a ratio of 0:1 to 4.5:1. Most preferably, the maximum stretching ratio is e, s:i, and the stretching is performed at a high temperature as high as 250°C, and the stretching is performed at a maximum of about 30°C while heating in the relaxation stage.
%. The finished cooled monofilament is then wound onto a spool.

The monofilament of the invention is manufactured according to the previous steps. Typical examples are as follows.

Examples 11 and I2 65% by weight of pellets of polyester resin Merge 1934 from DuPont, post-condensed in solid form and having an intrinsic viscosity of 05, and pellets of Dexin 445D thermoplastic polyurethane resin with a durometer hardness of 45 according to the D scale. A uniform mixture of 35% by weight was placed in the hopper of an injection molding machine and injection was performed. The injection conditions are as follows, although they are not considered to have any limitations.

1st heater zone temperature = 260°C 2nd heater zone temperature: 265°C 3rd heater zone temperature: 265°C Extruder die temperature: 265°C The extruder die has 8 0.80μl holes. pcs open. The final monofilament size is 0. It was 301-. 2 than monofilament in water at 66℃
．． It was rapidly cooled at a position 0 cm below. The quenched monofilament was drawn in a true air oven at a temperature of 74° C. at a draw ratio of 3.36, and the final draw ratio was increased to 5.0.
The film was stretched in an air oven at a temperature of 230°C and then relaxed at 280°C. The finished monofilament was scooped up and subjected to testing. In a second similar run, a similar monofilament was made with 73% polyester, 26% polyurethane, and 1% stabilizer.

For comparison, polyester resin was injected into monofilament using the same injection conditions as described for the polyester-polyurethane blend.

We tested the physical properties of three types of materials.
The results are shown below.

Polyester 65% PET-35% tensile strength km / n( tensile elongation elastic modulus lue/bo to 220℃ Shrinkage degree at Abrasion resistance* 5゜ 55° 0° Tensile strength kg / n( tensile elongation TPU 55X10' 2, 88X109 7% 73.2% 70X10' 0, 40xlO' 10.5% 7.9% 3, 2, 8 73%PET-26% TPU-1% stabilizer 2, 83X109 62,0 elastic modulus ni+a/m 0° 44 × O9 to 20℃ Shrinkage degree at 13° Abrasion resistance* 1゜ *Measured in weight loss (%) according to the method previously described

Claims (1)

[Claims] 1. At least one set of yarns woven in the primary direction of the woven fabric, essentially from 60% to 90% by weight polyethylene terephthalate, and from 40% to 10% by weight.
The yarn contains monofilaments formed from a thermoplastic polyurethane blend containing from zero to about 5% hydrolytic stabilizers in the secondary direction of the woven fabric, which is essentially perpendicular to the primary direction. A formed fabric for the paper industry characterized by being composed of at least one set of woven threads. 2. The molded fabric for paper manufacturing according to claim 1, wherein at least one set of threads woven in the primary direction of the woven fabric is made of polyethylene terephthalate monofilament. 3. The molding for paper manufacturing according to claim 2, wherein at least one set of yarns woven in the secondary direction of the woven fabric comprises a mixture of monofilaments made of polyethylene terephthalate and monofilaments made of a blend of polyethylene terephthalate and thermoplastic polyurethane. cloth. 4. Regarding monofilament by blending, the viscosity of the polyester used is 1, 1, 2,
2. A molded fabric for the paper industry according to claim 1, which has a viscosity of at least 0.50 when measured in a solvent consisting of 60:40 parts by weight of 2-tetrachloroethane. 5. The molded fabric for paper manufacturing according to claim 4, wherein the polyester has an intrinsic viscosity in the range of 0.95 to 1.20. 6. The molded fabric for the paper manufacturing industry according to claim 1, wherein the blended monofilament has a hardness of 95 or less on a Type A durometer of the polyurethane used. 7. The molded fabric for the paper manufacturing industry according to claim 1, wherein the blended monofilament has a hardness of 75 or less on a D-type durometer of the polyurethane used. 8. Formed fabric for the paper industry according to claim 1, wherein for the blended monofilaments, the polyurethane is an ester-based thermoplastic polyurethane polymer. 9. Formed fabric for the paper industry according to claim 1, wherein for the blended monofilaments, the polyurethane is an ether-based thermoplastic polyurethane polymer. 10. The molded fabric for paper manufacturing according to claim 1, wherein the blended monofilament contains at least 20% by weight of polyurethane. 11. The paper industry forming fabric of claim 1, wherein the blended monofilaments contain from about 25% to about 35% by weight of polyurethane. 12. A molded fabric for the paper industry according to claim 1, wherein the blended monofilaments contain about 30% by weight of polyurethane. 13. The blend contains about 0.3% to about 5% stabilizer by weight.
Formed fabric for paper industry according to claim 1 containing % by weight. 14. The blend contains about 0.7% to about 3% by weight of stabilizer.
% by weight. 15. The formed fabric for the paper industry according to claim 1, wherein the blend does not contain a stabilizer. 16. Part of the monofilaments that form the surface of the molded cloth covered with cellulose fiber pulp slurry are polyethylene terephthalate blended with thermoplastic polyurethane, and most of the monofilaments that form the machine side of the molded cloth are made of thermoplastic polyurethane and polyethylene terephthalate. a blend, wherein the blend comprises from 60% to 90% by weight polyethylene terephthalate and from 40% to 10% by weight thermoplastic polyurethane, and further comprises from 0 to about 5% by weight.
A molded fabric for the paper manufacturing industry, characterized in that it is used in a paper manufacturing machine, to which a hydrolysis stabilizer has been added. 17. Most of the monofilaments that form the surface of the molded cloth covered with cellulose fiber pulp slurry are polyethylene terephthalate, and some are polyethylene terephthalate blended with thermoplastic polyurethane, and the monofilaments that form the machine side of the molded cloth are 17. The paper industry forming fabric of claim 16, wherein a portion is polyethylene terephthalate and a major portion is a blend of thermoplastic polyurethane and polyethylene terephthalate. 18. The molded fabric for paper manufacturing according to claim 16, wherein most of the monofilaments, which are a blend of polyester and polyurethane, are laid in the machine cross-sectional direction of the woven fabric. 19. A formed fabric for the paper industry according to claim 18, wherein all of the monofilaments of the blend are laid essentially in the machine cross-sectional direction of the woven fabric. 20. Regarding the blended monofilament, the intrinsic viscosity of the polyester used is 1, 1 with phenol at 30°C.
2,2-tetrachloroethane in a solvent of 60:40 parts by weight of at least 0.50. 21. The intrinsic viscosity of polyester is 0.95 to 1.20.
A molded fabric for the paper industry according to claim 16, which falls within the scope of claim 16. 22. The molded fabric for the paper industry according to claim 16, wherein the polyurethane used has a hardness of 95 or less on an A-type durometer for the blended monofilaments. 23. The molded fabric for the paper manufacturing industry according to claim 16, wherein the blended monofilament has a hardness of 75 or less on a D-type durometer of the polyurethane used. 24. The paper industry forming fabric of claim 16, wherein for the blended monofilaments, the polyurethane is an ester-based thermoplastic polyurethane polymer. 25. The paper industry forming fabric of claim 16, wherein for the blended monofilaments, the polyurethane is an ether-based thermoplastic polyurethane polymer. 26. A molded fabric for the paper industry according to claim 16, wherein the blended monofilaments contain at least 20% by weight of polyurethane. 27. The paper industry forming fabric of claim 16, wherein the blended monofilaments contain from about 25% to about 35% by weight polyurethane. 28. The paper industry forming fabric of claim 16, wherein the blended monofilaments contain about 30% by weight polyurethane. 29. The blend contains about 0.3% to about 5% stabilizer by weight.
% by weight. 30. The blend contains about 0.7% to about 3% stabilizer by weight.
17. Formed fabric for the paper industry according to claim 16, including % by weight. 31. A formed fabric for the paper industry according to claim 16, wherein the blend does not contain a stabilizer. 32. Formed fabric in a paper making machine woven from a plurality of synthetic resin threads aimed at imparting abrasion resistance to the woven fabric, essentially a polyester of high molecular weight polyethylene terephthalate with a content of 60% by weight or more to 90% by weight. and 40% by weight or less to 10% by weight of thermoplastic polyurethane, and further 0.
A molded fabric for the paper industry, characterized in that it is used as a thread for imparting abrasion resistance to monofilaments comprising 3 to 5% of a hydrolysis stabilizer. 33. Formed fabric in a papermaking machine woven from a plurality of synthetic resin yarns aimed at imparting abrasion resistance to the woven fabric, essentially a polyester of high molecular weight polyethylene terephthalate with a content of 60% by weight or more to 90% by weight. and 40% by weight or less to 10% by weight of thermoplastic polyurethane, and further 0.
A molded fabric for the paper manufacturing industry, characterized in that it is used as a monofilament, which is intended to impart abrasion resistance to a monofilament comprising 3 to 5% of a hydrolysis stabilizer. 34, polyester consisting essentially of 60% or more to 90% by weight of high molecular weight polyethylene terephthalate; and 4
A molded fabric for the paper industry, characterized in that it is a melt-injected monofilament comprising from 0% to 10% by weight of a thermoplastic polyurethane and further from 0.3 to 5% of a hydrolysis stabilizer. 35. The intrinsic viscosity of polyester is at least 0.5 when measured at 30°C in a solvent consisting of 60:40 parts by weight of phenol and 1,1,2,2-tetrachloroethane.
35. The formed cloth for paper manufacturing industry according to claim 34, which is 36. The intrinsic viscosity of polyester is 0.95 to 1.20.
A molded fabric for paper manufacturing according to claim 35 within the scope of claim 35. 37. The molded fabric for paper manufacturing according to claim 34, wherein the polyurethane has a hardness of 95 or less on an A-type durometer. 38. The molded fabric for paper manufacturing according to claim 34, wherein the polyurethane has a hardness of 75 or less on a D-type durometer. 39. The paper industry forming fabric of claim 34, wherein for the blended monofilaments, the polyurethane is an ether-based thermoplastic polyurethane polymer. 40. A molded fabric for the paper industry according to claim 34, wherein the polyurethane is an ester-based thermoplastic polyurethane polymer. 41. The paper industry forming fabric of claim 34 comprising at least 20% by weight polyurethane. 42. The paper industry forming fabric of claim 34 comprising at least about 25% to about 35% by weight polyurethane. 43. The paper industry forming fabric of claim 42 comprising about 30% by weight polyurethane. 44. The paper industry forming fabric of claim 34, wherein the blend includes about 0.3% to about 5% stabilizer. 45. The paper industry forming fabric of claim 34, comprising from about 0.7 to about 3% stabilizer in the blend. 46. Claim 3 where the blend does not contain a stabilizer
The molded fabric for paper manufacturing according to item 4. 47. A monofilament comprising 60% to 90% by weight of polyester, 40% to 10% by weight of polyurethane, and furthermore 0 to 5% by weight of a hydrolytic stabilizer, kneaded in a specific manner, claimed as a monofilament. 34, by melt injection of the mixture through a die, quenching the injected monofilament, hot drawing the quenched monofilament in at least one drawing pass, and relaxing the drawn monofilament at an elevated temperature. 35. A method for forming a formed cloth for paper manufacturing according to claim 34, which further comprises cooling the cloth. 48. The method for forming a molded cloth for paper manufacturing according to claim 47, wherein the injection temperature ranges from 265°C to 275°C. 49. The formed fabric for paper manufacturing according to claim 47, which is stretched at least twice at different temperatures and with a final stretching ratio of 3.0:1 to 6.0:1. molding method. 50. A method of forming a paper industry fabric according to claim 47, wherein the monofilament is relaxed by about 25%. 51. A method of forming a papermaking fabric according to claim 47, using from about 0.3 to about 5.0% by weight of stabilizer. 52. A method of forming a papermaking fabric according to claim 47, using from about 0.75 to about 3.0% by weight of stabilizer. 53. A method for forming a forming cloth for paper manufacturing according to claim 47, which does not use a stabilizer. 54. The formed fabric for the paper industry according to claim 34, comprising a plurality of melt-injected monofilaments, at least some of which are melt-injected monofilaments. 55. A molded fabric for the paper industry according to claim 34, comprising staple fibers consisting of a portion of melt-injected monofilament having a length of discrete values. 56. A molded cloth for paper manufacturing according to claim 55, which is made of a spun yarn incorporating staple fibers. 57. at least one multifilament is comprised of a plurality of melt-injected monofilaments, at least some of the monofilaments are melt-injected monofilaments;
The formed fabric for paper manufacturing according to claim 34, further comprising a composite yarn consisting of staple fibers and a multifilament partially containing melt-injected monofilament in which at least some of the staple fibers have discrete lengths.