Films and Fabrics

Abstract

To provide a film that allows a visible light beam to sufficiently pass through it and sufficiently blocks infrared rays, with a low content of first particles, namely, a low content of tungsten oxide, indium oxide and antimony oxide.SOLUTION: A film comprises thermoplastic resin, first particles, and second particles. The first particle is at least one selected from the group consisting of tungsten oxide microparticles, antimony oxide microparticles and indium oxide microparticles. The content of the first particles is 0.1-5.0 g / m2 relative to the total area of the film. The second particle is at least one selected from the group consisting of titanium oxide and zinc oxide. The second particles have an average particle size of 500-4000 nm. The content of the second particles is 0.05-5.0 g / m2 relative to the total area of the film.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to films and fabrics. [Background technology]

[0002] In agriculture, high temperatures in summer can cause poor growth and quality damage to crops, resulting in reduced productivity. In greenhouses for horticultural crops (hereafter referred to as greenhouses), the temperature inside the greenhouses rises, increasing the risk of workers suffering from sunstroke and heat stroke every year due to rising temperatures caused by recent climate change. To address these issues, the use of sunshade sheets has traditionally been used to prevent the temperature inside the greenhouses from rising due to sunlight.

[0003] However, when a sunshade sheet is placed over a greenhouse, it blocks infrared rays that cause heat, but at the same time, it also blocks visible light that is necessary for crop growth, which is a problem.

[0004] In response to the above-mentioned problems, a sunshade sheet is known in which uniaxially oriented yarns containing tungsten oxide fine particles that have infrared shielding properties are crossed lengthwise and widthwise (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-050307 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the present inventors have found that conventional sunshade sheets have the following problems. As described above, the sunshade sheet described in Patent Document 1 is a sunshade sheet formed by crisscrossing uniaxially oriented yarns containing tungsten oxide fine particles as an infrared shielding agent in both longitudinal and transverse directions. While this sheet has high performance in selectively transmitting or blocking visible light and infrared light, it has the problem of requiring a large amount of tungsten, which is difficult to obtain due to its limited production volume.

[0007] In view of the above problems, the present invention aims to provide a film that combines excellent visible light transmittance and excellent infrared shielding properties, and further contains a specific amount of second particles, thereby reducing the content of first particles, i.e., reducing the content of tungsten. [Means for solving the problem]

[0008] In order to solve the above problems, the film of the present invention is as follows. That is, (1) A film containing a thermoplastic resin, first particles, and second particles, wherein the first particles are one or more types selected from the group consisting of tungsten oxide fine particles, antimony oxide fine particles, and indium oxide fine particles, and the content of the first particles is 0.1 to 5.0 g / m of the area of ​​the film. 2 the second particles are one or more selected from the group consisting of titanium oxide and zinc oxide, the average particle size of the second particles is 500 to 4000 nm, and the content of the second particles is 0.05 to 5.0 g / m with respect to the area of ​​the film. 2 It is a film that (2) It is preferable that the film is (1), in which the value obtained by dividing the content of the second particles by the content of the first particles is 0.05 to 1.0. (3) The film of (1) or (2) preferably has a thickness of 15 to 150 μm. (4) A woven fabric composed of a plurality of warp threads and a plurality of weft threads, wherein at least a portion of at least one of the plurality of warp threads and the plurality of weft threads is a tape-shaped yarn, and the tape-shaped yarn is composed of a film according to any one of (1) to (3). [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a film that has excellent visible light transmittance and excellent infrared shielding properties, and that contains a specific amount of second particles, thereby having a small content of first particles, i.e., a small content of tungsten. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below with reference to the accompanying drawings.

[0011] The film of the present invention is a film containing a thermoplastic resin, first particles, and second particles, the first particles being one or more types selected from the group consisting of tungsten oxide fine particles, antimony oxide fine particles, and indium oxide fine particles, and the content of the first particles is 0.1 to 5.0 g / m with respect to the area of ​​the film. 2 The second particles are one or more selected from the group consisting of titanium oxide and zinc oxide, the average particle size of the second particles is 500 to 4000 nm, and the content of the second particles is 0.05 to 5.0 g / m of the film area. 2 Here, the first particles have a function of selectively blocking infrared rays, and the second particles have a function of selectively scattering infrared rays.

[0012] The film of the present invention, which has all of these characteristics, achieves both excellent visible light transmittance and excellent infrared shielding properties, and furthermore, by containing a specific amount of second particles, it is possible to provide a film with a reduced content of first particles. Note that in this specification, the first particles, which are one or more types selected from the group consisting of tungsten oxide microparticles, indium oxide microparticles, and antimony oxide microparticles, may be referred to as an infrared shielding agent, and the second particles, which are one or more types selected from the group consisting of titanium oxide and zinc oxide, may be referred to as a scattering agent.

[0013] Next, the mechanism by which the film of the present invention exhibits excellent infrared shielding properties even when the content of the first particles is small is presumed to be as follows. That is, the film of the present invention contains a thermoplastic resin and a specific amount of first particles and a specific amount of second particles, thereby blocking infrared rays within the film and scattering the infrared rays within the film. Here, the first particles have the ability to selectively block infrared rays. Here, infrared rays refer to light rays in the infrared region (wavelength range of 781 to 2500 nm in the present invention). The first particles are preferably uniformly dispersed in the thermoplastic resin. In this case, the longer the path length of the light rays passing through the film, the more infrared rays the film blocks. Here, by containing a specific amount of second particles, the film of the present invention scatters and refracts infrared rays entering the film. Therefore, when infrared rays enter the film from a direction approximately perpendicular to the surface direction of the film, the path length of the infrared rays is longer when the infrared rays are refracted within the film than when they travel straight through the film. The longer the path length of the infrared rays, the more easily the infrared rays are blocked by the first particles. Furthermore, if the refracted infrared rays are further scattered by additional second particles, a phenomenon known as multiple scattering, the infrared path length may become even longer, and this effect becomes even more pronounced when the path length becomes even longer. The film of the present invention or a woven fabric using the film of the present invention can be used as a sunshade sheet. In this case, the film or fabric is often installed on the roof of a greenhouse. During times when it is necessary to suppress a rise in the temperature inside the greenhouse, infrared rays tend to enter the film from a direction approximately perpendicular to the roof surface of the greenhouse, i.e., the surface of the film contained in the film or fabric. Therefore, due to the above mechanism, the film of the present invention can lengthen the path length of infrared rays inside the film during times when it is necessary to suppress a rise in the temperature inside the greenhouse. As a result, even with a small content of the first particles, the film has excellent infrared blocking properties.

[0014] Here, by utilizing the principle of Mie scattering, the particle size of the second particles is designed to be half the wavelength at which it is most desired to scatter, thereby selectively extending the path length of the infrared light and increasing the probability that the infrared light will pass through the first particles, thereby achieving excellent infrared shielding properties. Details regarding the particle size of the second particles will be described later.

[0015] The film of the present invention contains a thermoplastic resin. Here, the film of the present invention preferably contains a thermoplastic resin as a main component. Here, "main component" means that the film contains more than 50% by mass of the thermoplastic resin based on the entire film. Specifically, any thermoplastic resin such as a polyolefin resin, a polyester resin, a methacrylic resin, or a polycarbonate resin can be used as this thermoplastic resin. From the viewpoint of productivity, polyethylene resin, polypropylene resin, or polyethylene terephthalate resin is preferred.

[0016] The film of the present invention has the first particles in an amount of 0.1 to 5.0 g / m 2 relative to the area of ​​the film. 2 This provides the film with excellent infrared shielding properties and excellent visible light transmittance, and furthermore, inhibits aggregation of the first particles inside the film. In addition, the film contains the first particles in an amount of 0.4 g / m2 relative to the area of ​​the film, because this improves the infrared shielding performance of the film. 2 It is preferable that the content is 0.8 g / m or more. 2 On the other hand, it is more preferable that the film contains the first particles in an amount of 4.0 g / m2 or more relative to the area of ​​the film, because this further suppresses a decrease in the transmittance of visible light and further suppresses aggregation of the first particles. 2 It is preferable that the content is 3.0 g / m or less. 2 It is more preferable to contain the following:

[0017] Specifically, the first particles are one or more selected from the group consisting of tungsten oxide fine particles, indium oxide fine particles, and antimony oxide fine particles. Here, tungsten oxide fine particles mainly absorb infrared light with wavelengths of 780 to 2200 nm, indium oxide fine particles mainly absorb infrared light with wavelengths of 1100 to 2500 nm, and antimony oxide fine particles mainly absorb infrared light with wavelengths of 1300 to 2500 nm. Each type of particle absorbs infrared light, although in different wavelength ranges. Therefore, even if the film of the present invention contains only antimony oxide fine particles or only indium oxide fine particles, the optical path length of infrared light incident on the film from a direction substantially perpendicular to the film surface is increased by the above-described mechanism, resulting in the film's excellent infrared shielding properties.

[0018] These particles can be selected depending on the wavelength of infrared light to be blocked. When it is desired to effectively block infrared light having a wavelength of 780 to 2200 nm, the first particles are preferably composed primarily of tungsten oxide microparticles, and more preferably composed solely of tungsten oxide microparticles. Among tungsten oxide microparticles, cesium tungsten oxide is even more preferable because it can effectively absorb and block infrared light. Furthermore, when it is desired to effectively block infrared light having a wavelength of 1100 to 2500 nm, the first particles are preferably composed primarily of indium oxide microparticles, and more preferably composed solely of indium oxide microparticles. The indium oxide microparticles are even more preferably indium tin oxide. Here, the term "main component" refers to a specific substance contained in an amount greater than 50% by mass of the total mass of the first particles, preferably 80% by mass or more of the specific substance contained in the total mass of the first particles, and more preferably 95% by mass or more of the specific substance contained in the total mass of the first particles.

[0019] The second particles of the present invention are applied to the film at an amount of 0.05 to 5.0 g / m2 relative to the area of ​​the film. 2The film contains 0.05 g / m of second particles relative to the total mass of the film, because infrared rays can be sufficiently refracted inside the film and the film has excellent infrared shielding properties even with a small content of the first particles. 2 For the above reasons, the film contains the second particles at a concentration of 0.2 g / m2 relative to the area of ​​the film. 2 It is preferable that the content is 0.4 g / m or more. 2 On the other hand, it is more preferable that the film contains the second particles in an amount of 5.0 g / m2 or more relative to the film area, because this provides excellent visible light transmittance and can further suppress the aggregation of the second particles. 2 For the above reasons, the film contains the second particles at a concentration of 4.0 g / m2 relative to the area of ​​the film. 2 It is preferable that the content is 3.0 g / m or less. 2 It is more preferable to contain the following:

[0020] In the film of the present invention, the value obtained by dividing the content of the second particles by the content of the first particles is preferably 0.05 to 1.0. When the value obtained by dividing the content of the second particles by the content of the first particles is 0.05 or more, i.e., when the content of the second particles is higher than the content of the first particles, the amount of infrared light scattered by Mie scattering increases, and the film's infrared blocking ability is likely to be sufficient. When the value obtained by dividing the content of the second particles by the content of the first particles is 1.0 or less, i.e., when the content of the second particles is lower than the content of the first particles, the effect of the first particles, which do not utilize Mie scattering, is greater than the effect of the second particles, which utilize Mie scattering and are affected by particle size variation, and this is preferable because the decrease in visible light transmittance is limited.

[0021] The second particles contained in the film of the present invention are specifically one or more particles selected from the group consisting of titanium oxide and zinc oxide. Any of the particles may be polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, polyethylene butalate, polyamide, polyurethane, tetrafluoroethylene, Titanium oxide has a higher refractive index than common thermoplastic resins such as hexafluoropropylene copolymer and tetrafluoroethylene-perfluoroalkoxyethylene copolymer, and Mie scattering occurs at the interface between the thermoplastic resin and the second particles. Therefore, even if the film of the present invention contains only zinc oxide as the second particles, the aforementioned mechanism selectively extends the path length of infrared light, increasing the probability that the infrared light passes through the first particles, thereby achieving excellent infrared shielding properties. Titanium oxide is preferably used as the main component because of its high refractive index, which significantly differs from that of the thermoplastic resin, making it easier to achieve scattering effects even with small amounts. Titanium oxide is known to have rutile, anatase, and brookite crystal structures, and any of these can be used in the film of the present invention. Rutile and anatase types are preferred due to the availability of inexpensive industrial production methods and production facilities.

[0022] The average particle size of the second particles contained in the film of the present invention is within the range of 500 to 4000 nm, since they selectively scatter light with wavelengths of 780 to 2500 nm, i.e., infrared light, according to the Mie scattering principle. Titanium oxide and zinc oxide generally have a particle size distribution during industrial production. An average particle size of 500 nm or greater can reduce the scattering of visible light by particles smaller than the average particle size, which exist with a certain probability due to the particle size distribution. The average particle size of the second particles is more preferably 600 nm or greater, and even more preferably 700 nm or greater. Furthermore, as the average particle size decreases, the number of interfaces between the thermoplastic resin and the second particles per mass of the second particles increases. Because scattering occurs at the interface between materials with different refractive indices, increasing the number of interfaces between the thermoplastic resin and the second particles allows for sufficient effect even with a small amount of the second particles added. Therefore, the average particle size of the second particles is preferably 4000 nm or less. From the above perspectives, an average particle size of 3500 nm or less is preferred, and 3000 nm or less is more preferred.

[0023] The infrared-shielding function of the film of the present invention is primarily determined by the content of the first particles relative to the area of ​​the film and the content of the second particles relative to the area of ​​the film. The film thickness can be adjusted to any value by increasing or decreasing the content of the first particles and the second particles per volume of the film (i.e., by changing the volume concentration of each particle), but a thickness of 15 to 150 μm is preferred. The film thickness is preferably 15 μm or more, more preferably 20 μm or more, to ensure the mechanical strength of the film and to improve processability when weaving with openings provided as a countermeasure against strong winds. On the other hand, the film thickness is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 60 μm or less, to prevent deterioration in handleability due to increased weight and rigidity.

[0024] The film of the present invention is suitable for use in woven fabrics. The film of the present invention is used as a tape-like yarn, and a woven fabric at least partially using this tape-like yarn will be described below. This woven fabric is composed of a plurality of warp threads and a plurality of weft threads, and at least a portion of at least one of the plurality of warp threads and the plurality of weft threads is a tape-like yarn, and the film of the present invention is used in this tape-like yarn. That is, this fabric satisfies any one of the following conditions (1) to (3). (1) Some or all of the plurality of warp yarns are tape-like yarns, and none of the plurality of weft yarns are tape-like yarns. (2) Some or all of the plurality of weft yarns are tape-like yarns, and none of the plurality of warp yarns are tape-like yarns. (3) Some or all of the plurality of warp yarns are tape-like yarns, and some or all of the plurality of weft yarns are tape-like yarns.

[0025] In this woven fabric, the transmittance of visible light can be improved by eliminating points where tape-like yarns overlap and intersect with each other, and durability can be improved. For these reasons, it is preferable that this woven fabric further comprises a yarn material, and that a portion of one of the plurality of warps and the plurality of wefts is the tape-like yarn, and that the other of the plurality of warps and the plurality of wefts is the yarn material. For reasons of improved durability and suppression of misalignment of the tape-like yarns, it is more preferable that the woven fabric of this form of the present invention is a leno weave, and it is even more preferable that the plurality of warps or the plurality of wefts including the tape-like yarns comprises a yarn material in parallel with the tape-like yarn.

[0026] In another embodiment of the woven fabric having the film of the present invention, it is preferable to reduce the opening area from the viewpoint of improving the wavelength selectivity of transmitted light, and to achieve this, it is preferable that both the warp and weft are tape-like yarns. In this case, by reducing the thickness of the film and / or lowering the concentrations of the first particles and second particles in the film, it is possible to suppress a decrease in the transmittance of visible light at the intersections between the tape-like yarns.

[0027] The yarn material used in the woven fabric of the present invention is preferably a filament yarn made of a thermoplastic resin. The thermoplastic resin may be any thermoplastic resin fiber, such as polyester resin, polyolefin resin, acrylic resin, or polyamide resin. The filament yarn may be a monofilament or a multifilament.

[0028] The thread material used in the woven fabric of the present invention preferably has a flatness of 6 or less. It is more preferable that the flatness of the thread material is 5 or less, since this can improve the mechanical strength.

[0029] The total fineness of the filament yarns used in the woven fabric of the present invention is preferably 50 to 400 dtex. The total fineness of the filament yarns is more preferably 70 dtex or more, since this improves the durability of the woven fabric when used outdoors. On the other hand, the total fineness of the filament yarns is preferably 300 dtex or less, since this can prevent deterioration in handling and visible light transmittance due to stiffening of the woven fabric.

[0030] The thread material used in the woven fabric of the present invention preferably contains one or more selected from the group consisting of titanium oxide, zirconium oxide, magnesium oxide, aluminum oxide, silicon oxide, zinc oxide, and calcium carbonate in a content of 0 to 0.5 mass% relative to the total mass of the thread material. In this specification, one or more selected from the group consisting of titanium oxide, zirconium oxide, magnesium oxide, aluminum oxide, silicon oxide, zinc oxide, and calcium carbonate may be referred to as a matting agent. By containing a matting agent in an amount of 0.5 mass% or less relative to the total mass of the thread material, light incident on the thread material can be prevented from scattering outside the film through the thread material, thereby improving the visible light transmittance of the fabric. For the above reasons, it is preferable that the thread material does not contain a matting agent.

[0031] The film of the present invention can be post-processed to have functions such as an anti-fogging agent, an antifouling agent, a repellent, an insect repellent, an antibacterial agent, etc., within the scope of not impairing the effects of the present invention. Examples of methods for imparting functions include a dip-nip method and a spray method.

[0032] When the film of the present invention is expected to be used in an environment exposed to sunlight, such as outdoors in agricultural sheets, it is preferable to impart the film with an ultraviolet ray blocking agent or a light stabilizer to improve weather resistance. Examples of ultraviolet ray blocking agents include triazine derivatives and benzotriazole derivatives. Examples of light stabilizers include hindered amine derivatives. The ultraviolet ray blocking agent or light stabilizer may be imparted with the film by blending it into the film or by post-processing.

[0033] The film of the present invention is also suitable for use as a sunshade sheet, awning, shade, interior curtain, blind, etc. Here, these may contain sheet-like materials other than the film of the present invention, as long as the effects of the film of the present invention are not impaired. Specifically, when a woven fabric containing the film of the present invention is applied to an object to be applied, such as an agricultural greenhouse, if the width or length of the woven fabric is insufficient, the sunshade sheet may be formed by sewing the woven fabric and a sheet-like material other than the woven fabric together.

[0034] The light transmittance characteristics of the film of the present invention preferably include a visible light transmittance of 60% or more in the wavelength range of 380 to 780 nm and an infrared transmittance of 60% or less in the wavelength range of 781 to 2500 nm. By using the above film in an agricultural sheet, it is possible to introduce more visible light necessary for crop growth into the interior of an agricultural greenhouse, while at the same time blocking more infrared rays that cause an increase in the temperature inside the agricultural greenhouse. The visible light transmittance is more preferably 65% ​​or more, and even more preferably 70% or more. Furthermore, the infrared transmittance is more preferably 50% or less, and even more preferably 40% or less. Examples of means for obtaining such a film include using the materials described in Example 1 and employing the manufacturing method described in Example 1.

[0035] The tape-shaped yarn used in the woven fabric of the present invention preferably has a short side width of 1 to 15 mm. The short side width of the tape-shaped yarn is more preferably 2 mm or more, because this prevents the tape-shaped yarn from twisting and turning over when woven. On the other hand, the short side width of the tape-shaped yarn is more preferably 10 mm or less, because this improves the flexibility of the woven fabric and thereby improves handling. [Example]

[0036] The present invention will be described in detail below based on examples, but the present invention is not limited to these. The performances in the examples were measured by the following methods.

[0037] [Measurement method] (1) Visible light transmittance, infrared transmittance, and shielding rate Five 3mm x 30mm film test pieces were prepared. Using a spectrophotometer "UV-3600plus (Shimadzu Corporation)," the spectral transmittance of five points on each test piece was measured at 1nm intervals on one side and the other side of the test piece, from wavelengths of 380 to 2500nm. The average of the ten light transmittances measured at wavelengths of 380 to 780nm on each side was taken as the visible light transmittance (%). The average of the ten light transmittances measured at the five measurement points on each side and the other side of the test piece, from wavelengths of 781 to 2500nm, was taken as the infrared transmittance (%). The infrared shielding rate was calculated using the following formula: Infrared Shielding Rate [%] = 100% - Infrared Transmittance [%] The measurement conditions were: scan speed "medium speed," slit width "20 nm," detector unit "external (3 detectors)," S / R switching "standard," and slit program "standard."

[0038] (2) Identification of the material and average particle size of the first particle The particle size was determined by observing the cross section of the film under a transmission electron microscope (TEM) at 50,000x magnification. The particles in the film were qualitatively analyzed using energy dispersive X-ray spectroscopy to identify the material of the particles. The particle sizes of a total of 20 particles were measured, and the average particle size was determined by the arithmetic mean. If the cross section was not spherical, the particle in the TEM image was enclosed in a rectangle with the longest side, and the arithmetic mean value of the longest and shortest sides was taken as the particle size.

[0039] (3) Identification of the material and average particle size of the second particle The particle size was determined by observing the cross section of the film under a transmission electron microscope (TEM) at 20,000x magnification. The particles in the film were qualitatively analyzed using energy dispersive X-ray spectroscopy to identify the material of the particles. The particle sizes of a total of 20 particles were measured, and the average particle size was determined by the arithmetic mean. If the cross section was not spherical, the particle in the TEM image was enclosed in a rectangle with the longest side, and the arithmetic mean value of the longest and shortest sides was taken as the particle size.

[0040] (4) Film thickness Five 3mm x 30mm film test pieces were prepared. Two random locations on each test piece, a total of 10 film cross sections, were observed at 1,000x magnification using a scanning electron microscope (SEM). The film thickness was measured at three locations within the field of view: both ends and the center of the film. The arithmetic mean of the measured film thickness values ​​for a total of 30 films was taken as the film thickness.

[0041] (5) Film density The mass of 150 sheets of 3mm x 30mm film was measured using an electronic balance, and the area (3 x 30 x 150 = 13,500 mm) was calculated. 2 ) and (4) by the film thickness obtained in (5).

[0042] (6) Content of first particles The cross section of the film was observed randomly in 50 fields of view using a transmission electron microscope (TEM) at 50,000x magnification, and the number of particles was counted. The number of counted particles was multiplied by the average cross-sectional area of ​​the first particles calculated from the average particle size of the first particles determined in (2), and then divided by the total cross-sectional area of ​​the film observed in the 50 fields of view to determine the area ratio of the first particles to the film. This area ratio was raised to the power of (3 / 2) to determine the volume ratio of the first particles to the film. This volume ratio was multiplied by the density of the first particles to determine the mass of the first particles per film volume. The density of the first particles varies depending on the crystal structure, production method, etc., but the following density was used in the present invention. Tungsten oxide: 7.9 g / cm 3 , indium oxide: 7.1 g / cm 3, antimony oxide: 6.8 g / cm 3 . Thereafter, the mass of the first particles per film volume was multiplied by the film thickness determined in (4) to determine the content of the first particles per film area.

[0043] (7) Content of second particles The cross section of the film was observed randomly in 50 fields of view at 20,000x magnification using a transmission electron microscope (TEM), and the number of particles was counted. The number of counted particles was multiplied by the average cross-sectional area of ​​the second particles calculated from the average particle size of the second particles determined in (3), and then divided by the total cross-sectional area of ​​the film observed in the 50 fields of view to determine the area ratio of the second particles to the film. This area ratio was raised to the power of (3 / 2) to determine the volume ratio of the second particles to the film. This volume ratio was multiplied by the density of the second particles to determine the mass of the second particles per film volume. The density of the second particles varies depending on the crystal structure, production method, etc., but the following density was used in the present invention. Titanium dioxide: 4.2 g / cm 3 , Zinc oxide: 5.6g / cm 3 . Then, the mass of the second particles per film volume was multiplied by the film thickness determined in (4) to determine the content of the second particles per film area.

[0044] (8) Total fineness of yarn Based on JIS L 1018 (2010) 8.7.1, 25 threads were unraveled from the sample, and their length (mm) and mass (mg) were measured, and the total fineness of the thread material was calculated using the following formula. T=W / L×100 Here, T: Total fineness (dtex) W: Total mass of 25 threads (mg) L: Total length of 25 threads (mm)

[0045] (9) Flatness of yarn The cross section of the tape-like yarn or thread material was observed using a digital microscope (Keyence VHX-6000), and the ratio was calculated from the average value of the major axis length D / minor axis length d using the following formula, with 10 observation samples. Note that the value was rounded to the nearest tenth. Flatness=D / d.

[0046] [Example 1] A master chip was prepared by kneading and chipping polyethylene resin chips (Sumikathene F200, manufactured by Sumitomo Chemical Co., Ltd.) with a powder containing dispersed cesium tungsten oxide (tungsten oxide microparticles) (YMDS-874, 23% purity, manufactured by Sumitomo Metal Mining Co., Ltd.) at a ratio of 75:25. The resulting master chip, polyethylene resin chips (Sumikathene F200) serving as the base polymer, and titanium oxide powder (Teikai JR-1000, average particle size 910 nm) were kneaded and melted at 190°C in a mixer (Toyo Seiki Seisakusho Labo Plastomill) to a concentration of 1.2% by mass of the first particles and 0.25% by mass of the second particles. The resulting sample was pressed at 125°C and 5 MPa in a platen press to produce a 100 μm-thick film.

[0047] The visible light and infrared transmittance of the obtained film were as shown in Table 1.

[0048] [Examples 2 and 3] Films were produced in the same manner as in Example 1, except that the pressure of the platen press was changed so that the film thicknesses were 85 μm and 65 μm.

[0049] [Example 4] A film was produced in the same manner as in Example 1, except that the first particles were kneaded and melted to a concentration of 2.4 mass % and the second particles were kneaded and melted to a concentration of 0.5 mass %, and the pressure of the flat press was adjusted so that the film thickness was 50 μm.

[0050] [Examples 5 to 7] A film was produced in the same manner as in Examples 1 to 3, except that the second particles were kneaded and melted so that the content was 0.5% by mass.

[0051] [Comparative Example 1] A film was produced in the same manner as in Example 1, except that the second particles were not contained.

[0052] Comparative Example 2 A film was produced in the same manner as in Example 1, except that the second particles were changed to titanium oxide powder (R-730 manufactured by Ishihara Sangyo Kaisha, Ltd., average particle size 290 nm).

[0053] A comparison of Example 1 and Comparative Example 1 reveals that Example 1 has a higher infrared shielding rate than Comparative Example 1, which contains approximately the same amount of first particles. Furthermore, a comparison of Example 2 and Comparative Example 1 reveals that Example 2 has an infrared shielding rate equal to or higher than Comparative Example 1, even though the content of the first particles is approximately 15% less than Comparative Example 1.

[0054] Since the particle size of the second particles in Comparative Example 2 is small, the infrared shielding rate is inferior to that of Example 1, which contains the same amount of second particles, and it is clear that the decrease in visible light transmittance due to visible light being scattered by Mie scattering is significant.

[0055] [Table 1] [Industrial Applicability]

[0056] The film of the present invention is preferably used for agricultural sunshades, awnings, shades, interior curtains and blinds, etc.

Claims

1. A woven fabric composed of a plurality of warp threads and a plurality of weft threads, At least a part of at least one of the plurality of warp yarns and the plurality of weft yarns is a tape-like yarn, the tape-like yarn is composed of a film containing a thermoplastic resin, first particles, and second particles; the first particles are one or more types selected from the group consisting of tungsten oxide particles, antimony oxide particles, and indium oxide particles; The content of the first particles is 0.1 to 5.0 g / m with respect to the area of ​​the film. ２ and the second particles are one or more particles selected from the group consisting of titanium oxide and zinc oxide, the second particles have an average particle size of 500 to 4000 nm; The content of the second particles is 0.05 to 5.0 g / m with respect to the area of ​​the film. ２ A textile that is.

2. 2. The woven fabric according to claim 1, wherein a value obtained by dividing the content of the second particles by the content of the first particles is 0.05 to 1.

0.

3. A fabric as described in claim 1 or 2, wherein the thickness of the film is 15 to 150 μm.

Images