WO2004050973A1

WO2004050973A1 - Polyamide multifilament woven fabric and process for producing the same

Info

Publication number: WO2004050973A1
Application number: PCT/JP2003/014685
Authority: WO
Inventors: Hiroyuki Miyano; Noriki Fukunishi
Original assignee: Toyo Boseki Kabushiki Kaisya
Priority date: 2002-12-02
Filing date: 2003-11-18
Publication date: 2004-06-17

Abstract

A polyamide multifilament woven fabric characterized in that it has a thickness of 0.15 mm or less, a weight of 80 g/m2 or less, a tearing strength, as measured in the warp yarn cutting direction and/or weft yarn cutting direction by the single tongue method, of 1.5 kgf or greater and an air permeability of 1 cm3/cm2·s or less and that the sum of the numbers of single warp yarns and single weft yarns per 2.54 cm width thereof is 8000 or more. The polyamide multifilament woven fabric is suitable for use in, for example, material and apparel applications, such as a down wear, a down jacket, a down proof and a sleeping bag. There are provided a soft flexible high-strength thin woven fabric of low air permeability and a process for producing the same.

Description

Description Polyamide multifilament woven fabric and its manufacturing method

INDUSTRIAL APPLICABILITY The present invention is thin and lightweight, has low air permeability, has a soft and flexible texture, has excellent tear strength, and has excellent weaving properties with a polyamide multifilament woven fabric suitably used for apparel and materials. Manufacturing method. Background art

As represented by the art boom in recent years, consumers' leisure orientation has been increasing year by year, and as a result, apparel applications including sports fields such as skiing, snowport wear, and outdoor wear, clothing, sleeping bags, tents, paragliders, Demand for fabrics for materials such as parachutes is increasing. Textiles for materials such as sports clothing such as skis, snowwear, outdoor wear, and so on, sleeping bags, tents, paragliders, and parachutes are required to have high strength, and in particular, to improve tear strength. In particular, fabrics and base fabrics suitable for down wear, down jackets, down proofs, sleeping bags, and the like are required to be softer and more flexible, and to have functionality such as low air permeability and water resistance.

Hitherto, attempts have been made to increase the strength of polyamide filaments in order to obtain fiber products that require tear strength (for example, Japanese Patent Application Laid-Open No. H11-247702 (Claim 1)). A method for increasing the draw ratio to obtain a high-strength polyamide filament is disclosed. However, such yarns have a higher strength at 10% elongation and, conversely, a lower elongation, resulting in a harder fabric texture. Also, when the elongation is low, in the process of tearing the woven fabric, the number of yarns to be torn is reduced, and the stress per one yarn is concentrated, so that the tear strength is undesirably reduced. Also, if a yarn with a large fineness is used to increase the tear strength of the woven fabric, the woven fabric will be thick and the texture will be hard, making it unsuitable for applications requiring compact storage such as tents, paragliders and parachutes. In the weaving process, warp yarns are sometimes warped and woven without sizing in order to suppress the cost of such woven fabrics and base fabrics. Since it is limited to those with a relatively large single-fiber fineness, the fabric and the base fabric lack flexibility and softness. In the case where the woven fabric and the base fabric having a relatively large single-fiber fineness and a small number of single yarns per unit area as described above are subjected to calendering after dyeing to reduce air permeability, Both sides must be calendered, which increases costs.

The present invention is intended to solve the above-mentioned problems, and has a low air permeability that can be suitably used for materials such as downwear, down jackets, down proofs, sleeping bags, and clothing. And to provide a soft, flexible, high-strength thin fabric and a method for producing the same. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an example of a structure diagram of the polyamide multifilament woven fabric of the present invention. FIG. 2 is another example of a structure diagram of the polyamide multifilament fabric of the present invention. Disclosure of the invention

As a result of intensive studies on such problems, the present invention has been able to solve the above problems by the following means. That is, the present invention has the following configuration.

1. Fabric thickness 0. 1 5 mm or less, a fabric basis weight of 8 0 gZm ² or less, the tear strength is 1 in the warp cutting direction and Z or weft direction by Shin Gurutangu method. 5 kgf or more, air permeability 1 A polyamide multifilament woven fabric having a size of not more than cm ³ / cm ² · s and a total sum of single yarns of at least 800 between warp and weft of 2.54 cm.

2. The polyamide multifilament woven fabric according to the above item 1, wherein the warp and / or weft are polyamide multifilaments having a single yarn fineness of 1.5 dtex or less. 3. The method for producing a polyamide multifilament woven fabric according to the first or second aspect, wherein the relative viscosity is not more than 60 dtex, and the breaking strength is not less than 4.5 cN / dtex made from a polyamide resin having a relative viscosity of 2.5 or more. A method for producing a polyamide multifilament woven fabric, characterized in that weaving is performed using a polyamide multifilament having a breaking elongation of 35 to 50% as a warp and / or a weft.

4. The method for producing a polyamide multifilament fabric according to the above item 3, wherein the warp yarn is sized and then woven.

5. The method for producing a polyamide multifilament woven fabric according to the third or fourth aspect, wherein calendering is performed only on one side of the woven fabric. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The polyamide multifilament woven fabric of the present invention preferably has a woven fabric thickness of 0.15 mm or less, a woven fabric weight of preferably 80 g / m ² or less, and a warp cutting direction and a Z or weft cutting direction by a single-tander method. Preferably the tear strength is greater than 1.5 kgί (1 kg f = 9.8N). Polyamide multifilament is a fiber with high strength, high toughness, abrasion resistance, and excellent dimensional stability. Materials such as belts, hoses, tire cords, belts, sleeping bags, tents, parachutes, riders, parachutes, etc. It is suitable for use or for sports clothing such as ski / snowport wear and art doorwear. However, in the present invention, the target is mainly for use in thin and compact fabrics such as down wear, down jackets, down proofs, sleeping bags, etc., and the fabric thickness is preferably 0.15 mm or less, more preferably 0.13 mm. It is as follows. The fabric weight is preferably 80 gZm ² or less, more preferably 70 g / m ² or less, and still more preferably 60 gZm ² or less. It is preferable that the tear strength in the warp cutting direction and the warp or weft cutting direction by the single tundler method be 1.5 kgf or more (l kgf = 9.8 N). If it is less than 1.5 kgf, the tear strength of the woven fabric tends to be insufficient depending on the application, which is not preferable. It is more preferably at least 1.5 kgf in both processes and more preferably at least 1.8 kgf. In order to increase the tear strength, if the yarn is made with a resin having a relative viscosity that is too high in order to increase the fiber strength, the spinning operability may be impaired, and the tear strength of the woven fabric is 5.0 kgf or less. Is preferred. Then, the air permeability lc mV cm ² -. Is preferably not more than s, and more preferably 0 8 cmcm ² · s or less, more preferably 0 5 8 cm ³ Roh cm ² · s or less.. For applications such as down jeans, down jackets, down proofs and sleeping bags, woven fabric is used as side lining and stuffed. Therefore, if the air permeability of the woven fabric exceeds 1 cm ³ / cm ² · s, the fiber diameter is small, the crimp is small, the bristle-type wadding, and the stable are likely to protrude from the inside, which is not preferable. In order to achieve a low air permeability, it is preferable that the total number of single yarns between 2.54 cm (= 1 in) of the warp and the weft constituting the woven fabric of the present invention is 800 or more. The above means that the sum of the numerical value by the warp and the numerical value by the weft is 800 or more by multiplying the number of the filaments constituting the multifilament by the number of the warp or the weft of 2.54 cm. . Conventionally, in the case of nylon multifilament woven fabrics, when weaving warp yarns with no twist and no glue, nylon multifilaments with a relatively large single-filament fineness and a small number of filaments have been used. It was found that there was a limit in obtaining a fabric having low air permeability. Therefore, in order to obtain a low air permeability, it is preferable to use a multifilament having a large number of filaments and to obtain a woven fabric of the present invention by sizing. As a result, it is possible to finish the fabric with low air permeability and soft and flexible fabric. If the total number of single yarns between 2.54 cm of the warp and weft is less than 600, low air permeability cannot be obtained, and softness and flexibility tend to be insufficient, which is not preferable. More preferably, it is at least 1000, more preferably at least 1200. However, if the weaving density is set too high to increase the total number of single yarns between the 2.54 cm warp and weft yarns, weaving properties may be impaired. It is preferably at most 0.000. Regarding the balance of warp, it is not preferable that the ratio of warp or weft is too large, and the warp: weft is preferably in the range of 3: 7 to 7: 3, and more preferably 4: 3. 6-6: The range is 4. The polyamide multifilament fabric of the present invention is preferably subjected to calendering only on one side. As mentioned above, in the past, both sides of the fabric were calendered in order to obtain low air permeability, but this is a factor of cost increase, and glossiness appears on both sides of the fabric by calendering, This is not desirable because it is easily disliked. In the woven fabric of the present invention, by increasing the sum of the number of single yarns in the unit width with the above-mentioned warp and weft yarns, the denseness was improved, and only one side was calendered, and the air permeability was sufficiently low. It is preferable because a woven fabric can be obtained and one side having no strong gloss remains. The calendering may be performed multiple times on one side, provided that the heating temperature is 130 to 190 ° C and the heating pressure is 5 to 100 kg f / cm ² (l kg f / cm ² = 98066.5 Pa (Pascal) 9. 80665 X 10 ~ MPa), speed: 1 to 30 mZ, preferably 2 or 3 times.

The polyamide multifilament woven fabric of the present invention is woven at a high density using high multi-polyamide filaments so that the total number of single yarns between 2.54 cm of the warp and the weft is 8000 or more. is there. As a result, in the weaving process, warp fuzz and yarn breakage increase, so that it is preferable to perform sizing on the warp and then weave. Increased costs due to sizing and gluing are unavoidable, but increasing the quality and quality of weaving machines, weaving efficiency, and weaving productivity will not significantly increase overall costs, but rather lead to cost reductions. If the present invention is carried out without sizing, there are many disadvantages of greige and the production risk is high, which is not preferable.

The polyamide multifilament fabric of the present invention has a fineness of 60 dtex or less, a breaking strength of 4.5 cN / dtex or more, and a breaking elongation of 35 to 50 dtex using a polyamide resin having a relative viscosity of 2.5 or more. It is preferred to weave using 50% polyamide multifilaments for warp and / or weft. The single yarn fineness is preferably 1.5 dte X or less. In order to obtain high tear strength, the polyamide multifilament fabric of the present invention preferably has a relative viscosity of 2.5 or more, more preferably 3.0 or more, and even more preferably 3.5 or more. It is a polyamide multifilament formed by spinning. That As a result, despite having a relatively high breaking strength of 4.5 cNZd tex or more, it is characterized by a high breaking elongation of 35 to 50%. If the relative viscosity is less than 2.5, it becomes difficult to obtain such a high strength and high elongation type multifilament, which is not preferable. The breaking strength is more preferably 5.5 OcN / dtex or more, and even more preferably 5.5 cN / dteX or more. However, if the relative viscosity is too high, the yarn operability may be impaired. Therefore, the relative viscosity is preferably 5.0 or less. Also, if the breaking strength is too large, the breaking elongation becomes too low and the texture may become hard, so the breaking strength is preferably 10 cN / dtex or less. The fineness of the multifilament is preferably 60 dtex or less, more preferably 50 dte, and still more preferably 40 dtex or less in order to obtain the thinness and lightness of the woven fabric. The method for producing these polyamide multifilaments is not particularly limited, but it can be produced by a continuous spin-drawing apparatus using a spin draw method, or by performing a spin-drawing apparatus and a drawing apparatus in two steps. In the case of the spinning method, the peripheral speed of the spinning godet roller is preferably 1500 to 4000 mZ, more preferably in the range of 2000 to 3000 mZ, and it is continuously stretched and stretched to have a breaking strength of 4.5 cN / dtex or more and a breaking strength of 35 to 50. It is preferable that the elongation at break is adjusted to%.

The woven fabric of the present invention is mainly used for materials such as sleeping bags, tents, paragliders, parachutes, skis, snowboard wear, art doorwear, and clothing, so that a strong and solid fabric is required. Therefore, the preferred organization of woven fabric is a flat organization, which has the most organizational points, or a ripstop organization that combines a flat organization, a stone, and a Nanako organization. Above all, it is preferable to use a ripstop structure in order to obtain a woven fabric having a large tear strength, and the number of stones and nanaco in the lip stop structure may be two or more. Generally, it is configured in the range of 2 to 5, and a double rip stop may be used. In the present invention, there is no detailed limitation of the rip stop structure. However, in the case of a ribstop structure, if the size of the grid pattern is too large, the effect of improving the tear strength of the entire fabric tends to be poor, so the grid pattern is preferably 1 to 2 cm, more preferably a grid pattern of 1 cm or less. It is desirable to design a woven fabric. The polyamide multifilament polymer constituting the polyamide filament fabric of the present invention is a synthetic polymer having an amide bond, and is represented by nylon 6, nylon 46, nylon 66, or the like.From the viewpoint of softness and cost, nylon is used. 6 is particularly preferably employed. It may be a copolymer or a mixture mainly composed of them. In order to improve the hygroscopicity, a hygroscopic monomer may be copolymerized. Also, in the multifilament spinning stage, the core-sheath type duplex in which a hygroscopic resin is confined in the core is not particularly limited, and the cross-sectional shape of the filament constituting the polyamide multifilament fabric of the present invention is not particularly limited. In addition to the hollow, cross, and flat types, any special cross section can be applied, and it may be an aggregate of different cross sections, and the degree of irregularity and the hollow ratio are not particularly limited. However, since a glossiness that is too strong is often not preferred, a round cross-section that does not cause a sense of strangeness in the glossiness is particularly preferred. Also, so-called thick and thin yarn having thick and thin spots in the fiber axis direction may be used.

The filament constituting the polyamide multifilament fabric of the present invention may contain a hygroscopic substance, an antioxidant, a matting agent, an ultraviolet absorber, an antibacterial agent, etc., alone or in combination. In addition, there is no particular limitation on properties other than the strong elongation properties of the polyamide multifilament, such as boiling water shrinkage, thermal stress, birefringence, and thickness unevenness. The polyamide multifilament may be subjected to crimping such as false twisting, or may be a mixed yarn or a composite yarn with filaments having different shrinkage rates or different cross-sectional shapes. Example

Hereinafter, the present invention will be described with reference to specific examples. The evaluation method used in the present invention is as follows.

(Explanation of evaluation method)

(Relative viscosity)

96.3 ± 0.1% by weight of the sample was dissolved in a special grade concentrated sulfuric acid so that the polymer concentration was 10 mg / m 1, and the sample solution was adjusted. ° C temperature Measure the relative viscosity of the solution using an Ostwald viscometer with water falling seconds of 6 to 7 seconds per degree. Using the same viscometer for measurement, the relative viscosity RV was determined from the ratio of the drop time TO (second) of 20 ml of sulfuric acid and the drop time T1 (second) of 20 ml of the sample solution, which were the same as when the sample solution was adjusted. It is calculated using the following equation.

RV = T 1 / T 0

(Rupture strength: DT (cN / d tex), elongation at break: DE (%))

It is measured using Instron Japan Model 4310. As the initial load, 1/33 g of the yarn fineness (dtex) was added, and an S—S chart was created under the conditions of a yarn length of 20 cm and a pulling speed of 2 Ocm / min. Measure in 3 and read the breaking elongation and breaking strength from the chart, calculate the average value of each, and calculate the breaking strength by dividing by the fineness (dtex).

(Fineness (d t e X))

Three 10 Om long polyamide multifilament cases were prepared, the weight (g) of each was measured, the average value was determined, and the result was multiplied by 100.

(Air permeability)

J I S-L-1096 Measured using the air permeability (Fragile method A) specified in 8.27.1.

(Thickness)

For woven fabrics that have not been subjected to film processing such as coating and lamination, the thickness of the woven fabric (mm) is measured at five random locations using a thickness gauge, and the average value is obtained. For the woven fabric that has been subjected to film processing, the cross section is photographed using a scanning electron microscope, the distance between the outermost filaments on both sides of the woven fabric is randomly measured at five points, and the photographic magnification is converted. And find the average.

(Examples 1-3, Comparative Examples 1-2)

(Example 1)

Melting and discharging nylon 6 polymer with relative viscosity of 7? R = 3.51 from spinneret with 24 round holes at spinning temperature of 280 ° C, cooling, spinning with spinning godet roller, spinning at peripheral speed of 2 200 m / min, Continuous drawing heat setting, 33 decitex 24 filaments with a breaking strength of 6.50 cN / dtex and a breaking elongation of 43.0% A multifilament was obtained. The multifilaments are woven in a non-twisted state using a plus size (R) J-30 acrylate ester copolymer ammonium salt type manufactured by Ryo Kagaku Kogyo Co., Ltd. Weaving was performed with the ripstop structure shown in Fig. 1, using the untwisted state as it was without adding a mark. The weavability was good, no warp breakage and no fluff occurred, and the operability of the loom was high. The obtained greige was also of high quality. The resulting greige seminal鍊usual manner, after staining, calendering one machining: Finishing subjected twice (Conditions Cylinder temperature 1 20 ° C, pressures 25 Ji 111 ^2, speed 20 m / min) to the fabric one side A woven fabric having a warp density of 249 yarns of Z2. 54 cm and a weft yarn density of 137 yarns / 2.54 cm was obtained. The obtained woven fabric has a tear strength of 2.0 kgf, a weft tear strength of 1.5 kgί, a thickness of 0.10 mm, a basis weight of 55 gZm ² , and a permeability of 0.65 cm V cm ^2- s. The texture was very soft, and the fabric was excellent in tearing strength despite being thin, and also excellent in low air permeability. Table 1 shows the results.

(Example 2)

The relative viscosity 7? R = 3. ejecting molten nylon 6 polymer one 5 from a die having 3 four round holes at a spinning temperature of 28 5 ^D C, cooled, spun pick drawing by godet roller circumferential speed 2 30 OmZm in, Continuous stretching and heat setting were performed to obtain a multifilament of 44 decitex and 34 filaments having a breaking strength of 6.0 cN / dtex and a breaking elongation of 47.4%. Hereinafter, similarly to Example 1, the multifilament was glued for warp, and the weft was used as it was in a non-twist state, and weaving was performed with the ripstop structure shown in FIG. As in Example 1, the weaving property was good, no warp breakage, no fluff was generated, the operation rate of the loom was high, and the obtained looms had no defects. After the obtained greige is refined and dyed according to a conventional method, it is subjected to a force render process (condition: cylinder at a temperature of 120. C, pressure 25 kgf / cm ² , speed 20 m / min) twice on one side of the fabric to finish. A woven fabric having a warp density of 2 17 yarns / 2.54 cm and a weft yarn density of 1 19 yarns / 2.54 cm was obtained. The obtained woven fabric had a tear strength of 2.5 kgf, a weft tear strength of 1.8 kgf, a thickness of 0.10 mm, and a basis weight of 65 gZm ² . The texture is very soft, even on thin fabrics Nevertheless, it was a polyamide multifilament woven fabric having a high toughness and excellent tear strength. Table 1 shows the results.

(Comparative Example 1)

Relative viscosity 7? R = 2.5 Nylon 6 polymer is melted and discharged from spinneret having 12 round holes at spinning temperature of 255, and after cooling, spinning take-off godet roller is spun at a peripheral speed of 3 30 Om / min and continuously. Then, it was heat-set for stretching to obtain a multifilament of 33 decitex 12 filaments having a breaking strength of 4.0 cN / dtex and a breaking elongation of 43.0%. The multifilament was used as a woven warp in an untwisted state without using glue for both warp and weft in an untwisted state, and weaving was performed with the ripstop structure shown in FIG. In weaving, warp breaks were scattered, and although it was not always perfect, we were able to obtain greige. The resulting greige was fine鍊-stained according to a conventional method, calendering (conditions: a cylinder temperature of 12 0 ° C, pressures 251 ^ _§ 7.111 ^2, speed 20mZ min) up finishing the applied twice to the fabric one side A woven fabric having a warp density of 249 yarns and a width of 2.54 cm and a weft yarn density of 137 yarns and a width of 2.54 cm was obtained. The obtained woven fabric has a tear strength of 1.5 kgf, a weft tear strength of 1.0 kgf, a thickness of 0.10 mm, a basis weight of 55 g / m ² , and a permeability of 0.85 cmVcm ^2. -s. The texture was rather hard and the fabric had a slightly lower tear strength. Table 1 shows the results.

(Comparative Example 2)

Melting and discharging nylon 6 polymer with relative viscosity r = 3.51 from spinneret with 24 round holes at spinning temperature of 280 ° C, cooling, spinning at spinning take-off godet roller peripheral speed of 220 Om / min, and continuous drawing Heat setting was performed to obtain a 33 dtex 24 filament h multifilament having a breaking strength of 6.50 c NZd tex and a breaking elongation of 43.0%. The multifilament is woven as a woven warp in an untwisted state using an acrylic acid ester copolymer ammonium salt type plus size (R) J-30 manufactured by Ryogo Chemical Industry Co., Ltd. Weaving was performed using a flat plaque without using a twist. The weavability was good, no warp breakage and no fluff occurred, and the operating rate of the loom was high. The obtained greige is refined according to a standard method. The fabric was kneaded and dyed to obtain a woven fabric having a warp density of 244 yarns / 2.54 cm and a weft yarn density of 131 yarns / 2.54 cm. No calendar processing was performed. Resulting et fabrics are subjected tear strength is 1. 7 kg f, a weft tear strength is 0. 9 kgf, the thickness Hiroyoshi 0. 10 mm, basis weight 55gZm ^2, air permeability 1. ² cm ³ / cm 2 · S. The texture was very soft, but the tear strength was slightly weak and the breathability was slightly higher. Table 1 shows the results.

(Example 3)

Nylon 6 polymer with a relative viscosity of? 7 r = 3.5 is melted and discharged from a spinneret having 20 round holes at a spinning temperature of 285 ° C, and after cooling, it is drawn at a spinning take-off godet roller peripheral speed of 200 OmZm in and continuously. Then, the film was stretched and heat-set to obtain a multifilament of 22 decitex and 20 filaments having a breaking strength of 6.1 cN / dtex and a breaking elongation of 45.0%. Hereinafter, similarly to Example 1, the multifilament was glued for warp, and the weft was used as it was in a non-twist state, and weaving was performed with the rib stop structure shown in FIG. As in Example 1, the weaving property was good, no warp breakage, no fluff was generated, the operation rate of the loom was high, and the obtained looms had no defects. After the obtained greige is refined and dyed according to a conventional method, it is calendered (condition: cylinder temperature 120 ° C, pressure 25 kgf / cm ² , speed 20 m / min) twice on one side of the fabric to finish, and the warp density 200 A woven fabric having a density of 200 pieces / 2.54 cm and a weft density of 200 threads 2.54 cm was obtained. The resulting fabric strength after tearing is 1. 8 kgf, weft tear strength is 1. 5 kg f, the thickness 0. 07m m, basis weight was 37. 2gZm ^2. The texture was very soft, and it was a polyamide multifilament fabric having high toughness and excellent tear strength despite being thin. Table 1 shows the results. (table 1 )

Industrial applicability

According to the present invention, a light weight that can be suitably used for sleeping bags, tents, paragliders, parachutes, ski / snowport wear, outdoor wear, especially down wear, down jackets, down pulls, etc., and clothing. It is possible to provide a polyamide multifilament woven fabric which is excellent in tear strength and low air permeability even when thin, has a soft and flexible texture, and is excellent in compactness. Further, it has become possible to provide a method for producing a polyamide multifilament woven fabric as described above, which has excellent weaving properties and can suppress glossiness.

Claims

The scope of the claims

1. fabric thickness 0. 15 mm or less, the fabric basis weight is at 80 g / m ² or less, the thin Gurutangu method strong tearing in the warp cutting direction and Z or weft direction by the 1. 5 kg ί above, air permeability is 1 cm cm ² * _s or less, ^{2.5 for} warp and weft

A polyamide multifilament fabric, wherein the total number of single yarns between 4 cm is 8000 or more.

2. The polyamide multifilament woven fabric according to claim 1, wherein the warp and / or weft is a polyamide multifilament having a single yarn fineness of 1.5 dteX or less.

3. The method for producing a polyamide multifilament woven fabric according to claim 1 or 2, wherein the fineness is 60 dtex or less, and the breaking strength is 4.5 cN / dtex or more, made from a polyamide resin having a relative viscosity of 2.5 or more. A method for producing a polyamide multifilament woven fabric, comprising woven using a polyamide multifilament having a breaking elongation of 35 to 50% for a warp, a Z or a weft.

4. The method for producing a polyamide multifilament woven fabric according to claim 3, wherein the warp yarn is sized and then woven.

5. The method for producing a polyamide multifilament woven fabric according to claim 3, wherein calendering is performed only on one side of the woven fabric.