Heat-insulating fabric

Abstract

This heat-insulating fabric (1) comprises: a base material (10) having a fabric; a heat-insulating part (11) disposed on a surface of the base material (10) and having aerogel particles; and a protective layer (12) laid on the outside of the heat-insulating part (11). The aerogel particles have a spherical shape or a chamfered shape, and the thickness of the protective layer (12) is 0.03-3 mm.

Description

Heat-insulating fabric

[0001] The present disclosure relates to a heat-insulating fabric using an aerogel.

[0002] Utilizing the high heat-insulating property of aerogels, various heat-insulating materials have been developed. For example, Patent Document 1 describes a heat-insulating material produced by applying a paint in which silica aerogel is dispersed in a binder liquid to the entire surface of a substrate and drying it. Heat-insulating materials using silica aerogel are used not only in the automotive, housing, and home appliance fields but also, as described in Patent Documents 2 and 3, in clothing having high heat retention properties in the apparel field.

[0003] Japanese Patent Application Laid-Open No. 2020-29528, Patent No. 6641061, Utility Model Registration No. 3233325

[0004] Fabrics for clothing are required to have durability that can withstand washing and friction during use. However, in the cured product (heat-insulating layer) of a paint having silica aerogel, the particulate silica aerogel is merely fixed by a binder. To enhance the heat-insulating property, it is better to have a higher content of silica aerogel. However, when the content increases, the heat-insulating layer becomes brittle, and the silica aerogel particles are likely to fall off (powdering) during washing or the like. Also, the adhesiveness between the heat-insulating layer and the substrate is not sufficient, and there is a risk that the heat-insulating layer may peel off during washing or the like.

[0005] For example, Patent Document 2 describes an aerogel-containing laminated sheet in which thermoplastic resin film layers are arranged above and below an aerogel-containing intermediate layer in which aerogel particles are fixed to polyester composite fibers. In this aerogel-containing laminated sheet, the interlayer adhesion is enhanced by heat-sealing and integrating the thermoplastic resin film layer with the first and second padding layers laminated on both sides thereof. Patent Document 3 describes an aerogel-containing thermal garment in which a thermal insulation layer containing aerogel powder and an organic foaming material is arranged between a buffer layer made of synthetic fiber cotton and a fixing layer made of synthetic fiber fabric or nonwoven fabric lining. In this thermal garment, problems such as powder shedding, hardness, and washability in the thermal insulation layer are solved by combining the aerogel powder with the organic foaming material. Patent Documents 2 and 3 describe a form in which another layer is laminated on a layer containing aerogel particles, but no study focusing on the shape of the aerogel particles has been conducted to address the problem of suppressing the shedding of aerogel particles due to washing, etc. Furthermore, while clothing fabrics require flexibility to minimize stiffness during wear, Patent Documents 2 and 3 do not address the need to achieve both washability and flexibility.

[0006] This disclosure is made in view of the above circumstances, and aims to provide an insulating fabric that is excellent in heat insulation, washability, and flexibility.

[0007] (1) In order to solve the above problems, the heat-insulating fabric of the present disclosure comprises a base material having a fabric, a heat-insulating portion having aerogel particles disposed on the surface of the base material, and a protective layer laminated on the outside of the heat-insulating portion, wherein the aerogel particles have a spherical or beveled shape, and the thickness of the protective layer is 0.03 mm or more and 3 mm or less.

[0008] The aerogel particles constituting the insulating portion have a spherical or chamfered shape (a rounded shape with no sharp corners). In other words, the insulating portion includes at least one of spherical aerogel particles and chamfered aerogel particles. When the aerogel particles are not angular, there is less snagging when the fabrics rub or collide with each other during washing, and the snagging of water flow is also reduced, making it less likely for the aerogel particles to fall off. Furthermore, the closer the aerogel particles are to spherical, the higher the packing rate can be and the fewer the voids can be, making it more difficult for water to penetrate and suppressing their shedding. In addition, by placing a protective layer on the outside of the insulating portion, friction during use and impact during washing are mitigated, which also improves washability. Furthermore, by making the thickness of the protective layer 3 mm or less, the desired flexibility can be achieved. As described above, the insulating fabric of this disclosure is excellent in insulating properties, washability, and flexibility.

[0009] (2) In the above configuration, the protective layer may have one or more selected from fibers, leather, and resin. These materials can be made into cloth, film, sheet, etc., and are easy to apply to fabric.

[0010] (3) In any of the above configurations, the protective layer may be configured to have one or more selected from polyester fiber woven fabrics and nonwoven fabrics, polyester films, polyurethane sheets, and aluminum vapor-deposited films.

[0011] (4) In any of the above configurations, the heat insulating portion may be formed from a heat insulating portion composition comprising the aerogel particles, a urethane resin binder, a carbodiimide compound, and an isocyanate compound. The carbodiimide compound functions as a crosslinking agent for the urethane resin binder. The carbodiimide compound reacts with the urethane resin to generate urea bonds. This increases the number of crosslinking points and makes the three-dimensional mesh structure denser, thereby increasing the strength of the heat insulating portion. As a result, the retention force of the aerogel particles increases, making it less likely for the aerogel particles to fall off even after washing. The isocyanate compound mainly improves the adhesion between the heat insulating portion and the substrate. The isocyanate compound chemically bonds with hydroxyl groups on the surface of the substrate, improving the adhesion of the heat insulating portion to the substrate. This makes it less likely for the heat insulating portion to peel off even after washing. Thus, this configuration improves the washability of the heat insulating fabric.

[0012] (5) In any of the above configurations, the fabric may be made of polyester fibers. Fabric made of polyester fibers has advantages such as excellent quick-drying properties, high durability, and wrinkle resistance. Furthermore, polyester fibers contain hydroxyl groups. Even if the number of hydroxyl groups decreases due to dyeing or other processes, hydroxyl groups can be easily added by applying other surface treatments such as water-repellent treatment. Therefore, by using polyester fibers, the adhesion of the heat insulating part can be improved by chemically bonding the hydroxyl groups with the constituent materials of the heat insulating part.

[0013] (6) In any of the above configurations, the fabric may have a water-repellent properties. With this configuration, since the fabric constituting the base material has water-repellent properties, washability is improved. In addition, when forming an insulating part by applying a liquid insulating part composition to the base material, the penetration of the insulating part composition can be suppressed. Furthermore, if hydroxyl groups are imparted to the fabric by water-repellent processing, the adhesion of the insulating part can be improved by chemically bonding these hydroxyl groups with the constituent materials of the insulating part.

[0014] (7) In any of the above configurations, the aerogel particles may be composed of silica aerogel particles. Silica aerogel particles have a good balance between the size of the skeleton and the size of the pores, and exhibit excellent heat insulation properties. Therefore, this configuration is suitable for improving heat insulation properties. In addition, if hydrophobic regions are present on at least the surface of the outer surface and the interior (pore-forming surface) of the silica aerogel particles, water penetration is suppressed, which is suitable for improving washability.

[0015] (8) In any of the above configurations, the heat insulating portion may have a plurality of protrusions arranged in a dot-like pattern in a plan view.

[0016] Instead of forming the insulating layer, which contains relatively rigid aerogel particles, continuously across the entire surface of the substrate (so-called solid coating), arranging it in a dot-like pattern with gaps (spaces) in the planar direction—in other words, scattered like islands—improves the flexibility of the insulating fabric. Furthermore, since the spaces (air layers) between the protrusions are sealed by the substrate and protective layer, the insulating effect of the air layers is also exerted in addition to the insulating effect of the insulating layer, improving the overall insulation performance. In addition, water vapor can pass through more easily, giving the insulating fabric moisture permeability. Moreover, compared to forming the insulating layer across the entire surface of the substrate, the amount of aerogel used can be reduced, making it possible to lower the cost and reduce the weight of the insulating fabric.

[0017] The thermal insulation fabric of this disclosure is excellent in thermal insulation, washability, and flexibility.

[0018] This is a top view of one embodiment of the heat-insulating fabric of the present disclosure. This is a cross-sectional view taken in the direction of II-II in Figure 1. This is a scanning electron microscope (SEM) image of pulverized silica aerogel powder. This is an SEM image of unpulverized silica aerogel powder.

[0019] Embodiments of the heat-insulating fabric of this disclosure will be described below. However, the embodiments are not limited to those described below, and can be implemented in various modified and improved forms as possible for those skilled in the art. Numerical ranges using "~" in this specification indicate a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the individually described upper and lower limits can be combined arbitrarily. Furthermore, the upper and lower limits of the numerical ranges can be replaced with the values ​​shown in the examples.

[0020] <Thermal Insulation Fabric> First, an embodiment of the thermal insulation fabric of the present disclosure will be described with reference to the drawings. Figure 1 shows a top view of an embodiment of the thermal insulation fabric of the present disclosure. Figure 2 shows a cross-sectional view in the direction of II-II in Figure 1. In Figure 1, for the sake of explanation, the thermal insulation portion below the protective layer is shown as a transparent view with a dotted line. As shown in Figures 1 and 2, the thermal insulation fabric 1 comprises a base material 10, a thermal insulation portion 11, and a protective layer 12. The base material 10 is a woven fabric made of polyester fibers that has been treated with a hydrocarbon-based water-repellent agent to make it water-repellent. The thickness of the base material 10 is 0.12 mm.

[0021] The heat insulating portion 11 consists of a plurality of protrusions 110. The plurality of protrusions 110 are arranged in a dot pattern on the upper surface of the base material 10, spaced apart at regular intervals P. The composition, shape, and size of the plurality of protrusions 110 are all the same. The protrusions 110 have a hemispherical shape with a circular base. The height T of the protrusions 110 is 0.18 mm, the diameter L of the base is 2.5 mm, and the aspect ratio (T / L) is 0.07. When the surface area of ​​the base material 10 is taken as 100%, the total area of ​​the surface of the base material 10 covered by the protrusions 110 (heat insulating portion 11) is 22.7%. The protrusions 110 are formed from a heat insulating portion composition having silica aerogel particles, a urethane resin binder, a carbodiimide compound, an isocyanate compound, and a dispersant.

[0022] The protective layer 12 is laminated on top of the base material 10, sandwiching the heat insulating portion 11 (protrusion 110). The protective layer 12 is a woven fabric made of polyester fibers with a thickness of 0.3 mm. The protective layer 12 covers the protrusion 110.

[0023] Next, the individual elements constituting the thermal insulation fabric of the present disclosure will be described. The thermal insulation fabric of the present disclosure comprises a base material, a thermal insulation portion disposed on the surface of the base material, and a protective layer laminated on the outside of the thermal insulation portion. The thermal insulation fabric of the present disclosure only needs to have a base material, a thermal insulation portion, and a protective layer, and is not particularly limited to any other components.

[0024] [Base Material] The base material is a fabric. The fabric may be woven, knitted, or nonwoven. From the viewpoint of increasing strength, woven or knitted fabrics are preferable. The fabric may be a single layer or multiple layers laminated together. The material of the fabric is not particularly limited and may be appropriately selected according to the application of the heat-insulating fabric disclosed herein. Examples include chemical fibers such as polyester, nylon, acrylic, polyvinyl chloride, and polyurethane, and natural fibers such as cotton, linen, and wool. The fiber may be a single type or a mixture of multiple types. Among these, fabric made of polyester fiber has advantages such as excellent quick-drying properties, high durability, and wrinkle resistance. In addition, when using fibers having hydroxyl groups such as polyester, cotton, acrylic, and linen, the hydroxyl groups of the fabric may chemically bond with the constituent materials of the heat-insulating part, improving the adhesion of the heat-insulating part.

[0025] From the standpoint of improving washability and suppressing the penetration of liquid insulation composition during the formation of the insulation section, it is preferable that at least the fabric in contact with the insulation section be water-repellent. The water-repellent fabric may be made using fibers that are inherently water-repellent, made using fibers that have been treated with a water-repellent finish, or fabric that has been treated with a water-repellent finish. When treating fibers or fabric with a water-repellent finish, the water-repellent agent can be applied to the object to be treated, or the object to be treated can be immersed in the water-repellent agent. When treating fabric with a water-repellent finish, the water-repellent agent can be impregnated into part or all of the fabric, or a water-repellent layer can be formed on the surface of the fabric. In the latter case, the insulation section can be placed on the surface of the water-repellent layer. The type of water-repellent agent is not particularly limited and can be appropriately selected from hydrocarbon-based water-repellent agents, urethane-based water-repellent agents, silicone-based water-repellent agents, etc. If the water-repellent agent has hydroxyl groups, they may chemically bond with the constituent materials of the insulation section, improving the adhesion of the insulation section.

[0026] The base material may consist of cloth alone (with or without water repellency), cloth and a water-repellent layer placed on its surface, or a laminate in which other layers made of resin, elastomer, etc. are laminated onto the cloth. The surface of the base material on which the heat insulating portion is placed is preferably cloth or a water-repellent layer placed on its surface. The thickness of the base material can be appropriately determined according to the application. For example, if thinness or weight reduction is required, a thickness of 0.1 mm to 1 mm is suitable.

[0027] [Insulating part] The insulating part has aerogel particles. The aerogel particles have a skeleton formed by the linkage of multiple primary particles, with pores between the skeletons. The method for manufacturing the aerogel is not particularly limited, and the drying process may be carried out at atmospheric pressure or under supercritical conditions. Depending on the drying method used in manufacturing the aerogel, those dried at atmospheric pressure are sometimes called "xerogels" and those dried under supercritical conditions are sometimes called "aerogels," but in this specification, both (regardless of the drying method) are referred to as "aerogels."

[0028] The type of aerogel particles is not particularly limited. Examples of primary particles that form the aerogel skeleton include inorganic particles such as silica, alumina, zirconia, and titania. Among these, silica aerogel particles, in which the primary particle is silica, are preferable due to their excellent chemical stability. Silica aerogel particles are white and reflect infrared rays. Therefore, using silica aerogel particles can provide a heat-shielding effect to the heat-insulating part. Furthermore, if hydrophobic regions exist on at least the surface of the silica aerogel particles, both on the outer surface and the interior (pore-forming surface), water penetration is suppressed, which is suitable for improving washability.

[0029] Aerogel particles may be spherical or chamfered. That is, aerogel particles may consist only of spherical particles, only of chamfered particles, or both spherical and chamfered particles. "Spherical" is not limited to a perfect sphere, but includes shapes close to a sphere (nearly spherical). "Chamfered" means that the corners of the particles are rounded. In addition, aerogel particles may include particles other than spherical and chamfered particles, such as thin plate-like particles or angular, irregularly shaped particles, to the extent that they do not hinder the effects achieved by this disclosure. Aerogel particles may be used in their manufactured state, or they may be used after being pulverized. For pulverization, a pulverizing device such as a jet mill or a spheroidizing device may be used. By pulverizing, the corners of the particles are rounded, and chamfered particles can be easily obtained.

[0030] In terms of ease of application of the insulating composition for forming the insulating layer, and in terms of suppressing the shedding of aerogel particles and improving washability, it is preferable that the size of the aerogel particles be relatively small and uniform. For example, the 90% diameter (D) in the volume-based particle size distribution measured by laser diffraction / scattering method. ９０ The particle size should ideally be 200 μm, or even 150 μm or less.

[0031] The form of the thermal insulation is not particularly limited. For example, it may be a continuous layer that is continuous in the planar direction, a form that is discontinuously arranged in the planar direction, or a combination of these. Examples of forms that are discontinuously arranged in the planar direction include a form in which multiple protrusions are scattered in a dot-like, i.e., island-like manner when viewed from above, a form in which multiple protrusions are spaced apart from each other, and a form in which convex shapes intersect and are arranged in a grid pattern. When the thermal insulation is composed of multiple elements such as protrusions or convex shapes, the shape and size of the individual elements may be the same or different. The multiple elements may be evenly arranged in the planar direction, or they may be arranged to create a density in the planar direction by changing the distance (pitch) between adjacent elements.

[0032] The thickness of the insulating section (also called the height of the protrusions) should be 0.1 mm or more, and even 0.15 mm or more, from the perspective of improving thermal insulation. From the perspective of making it thinner to increase flexibility, it should be 1 mm or less, 0.85 mm or even 0.50 mm or less.

[0033] If the insulating section has protrusions, the extension of the protrusions can be straight, curved, or bent. The cross-sectional shape of the protrusions in the height direction can be a rectangle, trapezoid or other quadrilateral, a triangle, or a semicircle. From the viewpoint of reducing the impact received during washing and preventing the protrusions from falling off, it is preferable that the top of the protrusions have a curved shape, such as a semi-circular cross-section.

[0034] If the insulating portion has a protrusion, the shape of the protrusion may be hemispherical, cylindrical, conical, frustoconical, prismatic, pyramidal, or frustoconical. From the viewpoint of reducing the impact received during washing and preventing the protrusion from falling off, the top of the protrusion should be curved. In this specification, "hemispherical" is a concept that includes not only half of a perfect sphere (a hemisphere) but also shapes that are close to a hemisphere. In other words, "hemispherical" includes shapes that have a curved surface close to a hemisphere, such as a dome shape.

[0035] The aspect ratio, calculated by dividing the height of the protrusion by the maximum distance from the base, is preferably 0.01 or greater from the viewpoint of thermal insulation. A ratio of 0.02 or greater is more preferable. Furthermore, from the viewpoint of suppressing the detachment of the protrusion and improving washability, the aspect ratio is preferably 0.23 or less. A ratio of 0.20 or less is more preferable.

[0036] In a configuration where the insulating sections are arranged discontinuously in the planar direction, the total area of ​​the substrate surface covered by the insulating sections (the area of ​​the substrate surface covered by the insulating sections) should be between 8% and 65% of the total surface area of ​​the substrate, which is considered 100%. From the viewpoint of improving thermal insulation, it should be 10% or more, and even 20% or more. From the viewpoint of improving moisture permeability and flexibility, it should be 60% or less, and even 50% or less.

[0037] [Protective Layer] The protective layer is laminated on the outside of the insulation section (on the opposite side of the base material in the thickness direction). By covering the insulation section with the protective layer, the insulation section becomes less likely to come off due to friction during use or impact during washing. This improves durability and washability. In addition, the space (air layer) between the insulation sections is sealed by the base material and the protective layer, so in addition to the insulation effect of the insulation section, the insulation effect of the air layer is also exerted, improving insulation performance.

[0038] The thickness of the protective layer should be between 0.03 mm and 3 mm. From the perspective of protecting the insulation layer, a thickness of 0.1 mm or more, or even 0.3 mm or more, is preferable. From the perspective of increasing flexibility, a thickness of 2.5 mm or less, or even 2.0 mm or less, is preferable.

[0039] The form of the protective layer is not particularly limited and can be woven, knitted, nonwoven, film, or sheet. The material of the protective layer is also not particularly limited and can be fibers, leather, or resin. Examples include woven, knitted, nonwoven, leather sheets, and resin films made from chemical fibers or natural fibers. Among these, woven fabrics, nonwoven fabrics, polyester films, and polyurethane sheets made from polyester fibers are preferred due to their excellent durability, breathability, and flexibility. Nonwoven fabrics are also preferred because they contain air and provide heat insulation. The protective layer may consist of a single layer or be a laminate in which the same or different materials are laminated in two or more layers. Examples of laminates include metal-deposited films in which metal is deposited on the surface of a resin film by vacuum deposition or sputtering. Suitable metal-deposited films include aluminum-deposited films and titanium-deposited films.

[0040] <Method for Manufacturing Thermal Insulation Fabric> The thermal insulation fabric of this disclosure can be manufactured by applying a thermal insulation composition having aerogel particles to the surface of a substrate in a predetermined form, drying it, and then forming a protective layer. The protective layer may be formed by sewing, bonding, laminating, etc., depending on its form. The protective layer only needs to be laminated to the substrate via the thermal insulation part, and does not necessarily need to be fixed to the thermal insulation part and the substrate. When fixing the protective layer to the substrate, reducing the fixing area by fixing only around the periphery of the protective layer will prevent a decrease in thermal insulation performance. The components other than aerogel particles in the thermal insulation composition are not particularly limited, but considering durability, a form containing a urethane resin binder, a carbodiimide compound, and an isocyanate compound is desirable.

[0041] As the urethane resin binder, it is preferable to use a binder that uses water (including pure water and tap water) as a solvent (aqueous binder). Aqueous binders include water-soluble binders and emulsion-type binders, but emulsion-type binders (aqueous emulsion-type binders) are preferred because they are less likely to become sticky after the heat-insulating composition has hardened.

[0042] The carbodiimide compound is not particularly limited as long as it is a compound having a carbodiimide group in its molecule. Examples include dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, dicyclohexylmethanecarbodiimide, aqueous dicyclohexylmethanecarbodiimide, and aqueous tetramethylxylylenecarbodiimide. Considering compatibility with aqueous resins (urethane resin binders), water-soluble or water-dispersible carbodiimide compounds having hydroxyl groups at their terminals are preferred.

[0043] From the perspective of increasing the crosslinking density of the binder to enhance the retention force of the aerogel particles, the content of the carbodiimide compound is preferably 1 part by mass or more per 100 parts by mass of the urethane resin binder. 2 parts by mass or more is more preferable. On the other hand, from the perspective of heat insulation, it is desirable that the content of the compound that does not contribute to the improvement of heat insulation is small. Therefore, the content of the carbodiimide compound is preferably 10 parts by mass or less per 100 parts by mass of the urethane resin binder. 8 parts by mass or less is more preferable.

[0044] Examples of the isocyanate compound include aromatic diisocyanate compounds, aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, and mixtures thereof. Specifically, 4,4'-dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), 2,4,6-triisopropylphenyl diisocyanate (TIDI), 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), etc. can be mentioned.

[0045] From the perspective of improving the adhesion of the heat insulation part to the base material, the content of the isocyanate compound is preferably 3 parts by mass or more per 100 parts by mass of the urethane resin binder. 5 parts by mass or more is more preferable. On the other hand, from the perspective of heat insulation, it is desirable that the content of the compound that does not contribute to the improvement of heat insulation is small. Therefore, the content of the isocyanate compound is preferably 15 parts by mass or less per 100 parts by mass of the urethane resin binder. 10 parts by mass or less is more preferable.

[0046] The composition for the heat insulation part may contain a coupling agent, a dispersant, a flame retardant, etc. in addition to aerogel particles, a urethane resin binder, a carbodiimide compound, and an isocyanate compound. For example, when silica aerogel particles are used as the aerogel particles, by blending a silane coupling agent, the silica aerogel particles and the polymer skeleton of the urethane resin are bonded via the silane coupling agent, so that the retention force of the aerogel particles can be increased. The content of the coupling agent is preferably 0.1 part by mass or more with respect to 100 parts by mass of the urethane resin binder in order to exhibit its effect. On the other hand, from the viewpoint of heat insulation properties, the content of the coupling agent is preferably 3 parts by mass or less.

[0047] For example, silica aerogel particles have a small specific gravity and tend to float in water. Also, if they have hydrophobic sites on the surface or inside, they are less likely to be wetted by water. Therefore, when preparing the composition for the heat insulation part using water as a solvent, it is desirable to blend a dispersant in order to improve the dispersibility of the silica aerogel particles. Examples of the dispersant include surfactants and thickeners.

[0048] Surfactants include ionic surfactants (cationic surfactants, anionic surfactants, amphoteric surfactants) and non-ionic surfactants. Examples of the ionic surfactants include sodium carboxymethyl cellulose (CMC-Na), polycarboxylic acid amine salts, polycarboxylic acid ammonium salts, polycarboxylic acid sodium salts, TEMPO-oxidized cellulose nanofibers (CNF-Na), etc. Examples of the non-ionic surfactants include special polycarboxylic acid amine salts, polyethylene oxide (PEO), polyvinyl alcohol (PVA), etc. Also, it is preferable to use a non-ionic surfactant and an ionic surfactant in combination.

[0049] By incorporating a flame retardant, flame retardancy can be imparted to the heat-insulating portion. Any known flame retardants, such as halogen-based, phosphorus-based, or metal hydroxide-based agents, can be used. Considering the environmental impact, the use of phosphorus-based flame retardants is desirable. Examples of phosphorus-based flame retardants include ammonium polyphosphate, red phosphorus, and phosphate esters. Among these, those that are insoluble in water or coated with water-resistant resins are preferable because they are less likely to leach out even when in contact with moisture during use. For example, ammonium polyphosphate and resin-coated ammonium polyphosphate are suitable.

[0050] The composition for the heat insulating part may be prepared by mixing, for example, aerogel powder, urethane resin binder, carbodiimide compound, isocyanate compound, and other components added as needed, and stirring. If the urethane resin binder does not contain water, water may be added as appropriate during preparation. If the aerogel is silica aerogel, considering its dispersibility, it is desirable to add a dispersant to the urethane resin binder, or to a liquid of urethane resin binder in water, before adding the silica aerogel powder. Stirring may be done by blade stirring, but shear force may also be actively applied or ultrasonic waves may be applied. A rotational stirring device or a media-type stirring device may also be used.

[0051] The thermal insulation layer composition can be applied to the substrate by brushing, using coating machines such as screen printing, rotary screens, blade coaters, bar coaters, die coaters, comma coaters (registered trademark), and roll coaters, or by spraying. Alternatively, the substrate may be immersed in the thermal insulation layer composition. After application or immersion, the coating film should be dried and cured by holding it at a temperature of 80 to 150°C for about 5 to 20 minutes.

[0052] Next, the present disclosure will be described in more detail with reference to examples.

[0053] <Sample Preparation> [Example 1] First, a heat insulating composition (in parts by mass) with the composition shown in Table 1 below was prepared as follows. To water, a urethane resin emulsion as a urethane resin binder ("Permarine® UA-368" manufactured by Sanyo Chemical Industries, Ltd., 50% solids by mass), a nonionic surfactant as a dispersant (special polycarboxylic acid amine salt, "Nopcospers® 6100" manufactured by Sanopco Co., Ltd.), and a carboxymethylcellulose sodium salt (CMC-Na, "Celogen® BSH-12" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were added and stirred. Silica aerogel powder (pulverized product of "Aerogel Particles P200" manufactured by Cabot Corporation, 90% diameter (D ９０ The mixture was stirred with 150 μm of silica aerogel powder, a carbodiimide compound, and an isocyanate compound. Figure 3 shows an SEM image of the silica aerogel powder (pulverized) used. As shown in Figure 3, the silica aerogel powder used mainly consists of chamfered particles.

[0054] Next, a polyester fiber woven fabric (0.12 mm thick) was impregnated with a hydrocarbon-based water repellent ("Neoseed® NR-8800" manufactured by Nikka Chemical Co., Ltd.), and then heat-treated to produce a base material. The base material has water-repellent properties due to the water-repellent treatment with the hydrocarbon-based water repellent. Then, the prepared heat-insulating composition was screen-printed onto the surface of the base material in a dot pattern with a pitch of 2.5 mm to form raised areas. Here, the pitch is the distance between adjacent raised areas, and more specifically, it is the length of the portion of the line connecting the centers of the bottom surfaces of adjacent raised areas that does not overlap with the two bottom surfaces. For example, if the bottom surface of the raised area is circular, it is the distance between the centers of the raised areas minus the radius of the bottom surface of the two raised areas. All the formed raised areas have a hemispherical shape with a circular bottom surface, and all the raised areas are the same size. Finally, a 0.3 mm thick polyester fiber woven fabric was layered over the entire surface of the base material to cover the surface of the raised areas as a protective layer. In this way, a sample of the heat-insulating fabric of Example 1 was manufactured, in which a base material, multiple protrusions made of cured material of the heat-insulating composition, and a protective layer were laminated together. Table 1, shown later, shows the bottom shape, height, maximum length of the bottom (diameter in the case of a circular shape), aspect ratio, and pitch of the protrusions (the same applies to the other samples).

[0055] [Example 2] A sample of the heat-insulating fabric of Example 2 was manufactured in the same manner as in Example 1, except that the type of protective layer was changed to a polyester film with a thickness of 0.03 mm.

[0056] [Example 3] A sample of the heat-insulating fabric of Example 3 was manufactured in the same manner as in Example 1, except that the type of protective layer was changed to a woven cotton fiber fabric with a thickness of 1.0 mm.

[0057] [Example 4] A sample of the heat-insulating fabric of Example 4 was manufactured in the same manner as in Example 1, except that the type of protective layer was changed to a 3.0 mm thick polyester fiber nonwoven fabric.

[0058] [Example 5] A sample of the heat-insulating fabric of Example 5 was manufactured in the same manner as in Example 1, except that the shape and size of the protrusions were changed. In the sample of Example 5, the protrusions were prism-shaped with a rhombic base, with a height of 0.20 mm and a maximum length of 3.0 mm at the base.

[0059] [Example 6] A sample of the heat-insulating fabric of Example 5 was manufactured in the same manner as in Example 1, except that the shape and size of the protrusions were changed. In the sample of Example 6, the protrusions were rectangular prisms with a rectangular base, a height of 0.20 mm, and a maximum length of 6.0 mm at the base.

[0060] [Example 7] A sample of the heat-insulating fabric of Example 7 was manufactured in the same manner as in Example 1, except that the shape and size of the protrusions were changed. In the sample of Example 7, the protrusions have a triangular prism shape at the base, a height of 0.20 mm, and a maximum length of 2.3 mm at the base.

[0061] [Comparative Example 1] A sample of the heat-insulating fabric of Comparative Example 1 was manufactured in the same manner as in Example 1, except that a protective layer was not formed. The sample of Comparative Example 1 consists of a base material and a plurality of protrusions made of cured products of the heat-insulating composition formed in a dot shape on the surface of the base material.

[0062] [Comparative Example 2] A sample of the heat-insulating fabric of Comparative Example 2 was manufactured in the same manner as in Example 1, except that the type of protective layer was changed to a 3.5 mm thick polyester fiber nonwoven fabric.

[0063] [Comparative Example 3] A sample of the heat-insulating fabric of Comparative Example 3 was manufactured in the same manner as in Example 1, except that the type of protective layer was changed to a 3.2 mm thick polyurethane sheet.

[0064] [Comparative Example 4] A sample of heat-insulating fabric for Comparative Example 4 was prepared in the same manner as in Example 1, except that silica aerogel powder ("Aerogel Particles P200" manufactured by Cabot Corporation) was used without pulverization. For reference, Figure 4 shows an SEM image of the unpulverized silica aerogel powder. As shown in Figure 4, the unpulverized silica aerogel powder consists mainly of angular, irregularly shaped particles. The 90% diameter (D) of this silica aerogel powder ９０ The thickness is 450 μm.

[0065] <Evaluation Method> [Washability] The manufactured sample was cut into a rectangle measuring 280 mm in length and 210 mm in width, and the protective layer was fixed around the base material to create a sample for the washing test. The fixing method was as follows, depending on the type of protective layer (the same method was used for the samples used in the heat retention test and flexibility test below). Polyester woven fabric: The protective layer was sewn around the base material. Polyester film: The protective layer was welded around the base material. Cotton woven fabric: The protective layer was sewn around the base material. Polyester nonwoven fabric: The protective layer was welded around the base material. Polyurethane sheet: The protective layer was sewn around the base material. The prepared samples were subjected to a washing test based on JIS L1930:2024 "Household washing test method for textile products". For the washing test, a Type C standard washing machine was used, and washing according to washing method "C4M" in Annex E of the same JIS "Specifications for washing method of Type C standard washing machine (pulsator type)" was repeated 30 times. The drying method used was Method A (hanging drying).

[0066] The details of the washing method "C4M" specified in Annex E are as follows: Water temperature: 40 ± 3°C. Indicated water volume for washing and rinsing: 40 L. Washing process: Wash time 6 minutes, spin-drying time 3 minutes. First rinse process: Rinse time 2 minutes, spin-drying time 3 minutes. Second rinse process: Rinse time 2 minutes, spin-drying time 3 minutes. The mass of the sample was measured before and after the test, and the washability was evaluated based on the mass retention rate calculated by the following formula (I). Washability was evaluated as follows: a mass retention rate of 90% or more was a pass, and a rate of less than 90% was a fail. Mass retention rate (%) = Sample mass after washing / Sample mass before washing × 100 ... (I)

[0067] [Thermal Insulation (Heat Retention)] The manufactured sample was cut into a 300 mm x 300 mm square, and the protective layer was fixed around the base material to create a sample for heat retention testing. The prepared sample was subjected to a heat retention test based on "8.27.1 Method A (Constant Temperature Method)" of JIS L1096:2010 "Test Methods for Woven and Knitted Fabrics". An ASTM-type heat retention tester conforming to ASTM D 1518-85 was used as the heat retention tester. The temperature inside the heat retention tester was set to 20°C and the relative humidity (RH) to 65%, and the heat retention rate of the sample was calculated from the amount of energy used by the constant temperature heating element installed in the tester to maintain the temperature using the following formula (II). The size of the constant temperature heating element was 250 mm x 250 mm, the temperature was 36 ± 0.5°C, and the test time was 120 minutes after the temperature of the constant temperature heating element became constant. The sample was placed with the substrate side facing upwards (opposite side from the constant-temperature heating element). A higher heat retention rate indicates better thermal insulation. Thermal insulation was evaluated as follows: a heat retention rate of 10% or more was considered a pass, and a rate of less than 10% was considered a fail. Heat retention rate (%) = (Ho - Hc) / Ho × 100 ... (II) [Ho: heat loss from the constant-temperature heating element, Hc: heat loss when the constant-temperature heating element is covered with the sample]

[0068] [Flexibility] The manufactured sample was cut into a strip 20 mm wide and 150 mm long, and the protective layer was fixed around the base material to create a sample for flexibility testing. The prepared sample was subjected to flexibility testing based on JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics," "8.21 Stiffness and Softness," and "8.21.1 Method A (45° Cantilever Method)." The sample was placed with the protective layer side (convex side in Comparative Example 4) facing downwards. In this test, the shorter the distance the sample moved, the higher its flexibility. Flexibility was evaluated as follows: a movement length of 60 mm or less was considered a pass, and a movement length greater than 60 mm was considered a fail.

[0069] <Evaluation Results> Table 1 summarizes the composition of the thermal insulation composition used in the manufacture of the sample, the composition of the base material, the specifications of the thermal insulation part, and the evaluation results of the sample.

[0070] As shown in Table 1, the samples of Examples 1 to 7, in which the protective layer thickness was 3 mm or less, showed good washability, heat insulation, and flexibility. In contrast, the sample of Comparative Example 1, which did not have a protective layer, showed good heat insulation and flexibility, but did not achieve the desired washability. Furthermore, the samples of Comparative Examples 2 and 3, in which the protective layer thickness was greater than 3 mm, showed good washability and heat insulation, but their flexibility decreased. In addition, the sample of Comparative Example 4, in which silica aerogel particles with an irregular shape and relatively large particle size were included in the heat insulating portion (protrusions) without grinding the silica aerogel powder, showed good heat insulation and flexibility, but did not achieve the desired washability.

[0071] The heat-insulating fabric disclosed herein can be applied to a variety of items in the apparel, outdoor, and housing sectors. For example, it is suitable for clothing, hats, shoe insoles, gloves and other cold-weather gear, bedding, tents, picnic blankets, curtains, and wall materials.

[0072] 1: Insulating fabric, 10: Base material, 11: Insulating part, 12: Protective layer, 110: Protruding part.

Claims

1. A heat insulating fabric comprising a base material having a cloth, a heat insulating portion having aerogel particles disposed on the surface of the base material, and a protective layer laminated on the outside of the heat insulating portion, wherein the aerogel particles are spherical or beveled in shape, and the thickness of the protective layer is 0.03 mm or more and 3 mm or less.

2. The heat-insulating fabric according to claim 1, wherein the protective layer is one or more selected from fibers, leather, and resin.

3. The heat insulating fabric according to claim 1 or claim 2, wherein the protective layer is one or more selected from woven and nonwoven fabrics made of polyester fibers, polyester film, polyurethane sheet, and aluminum vapor-deposited film.

4. The heat insulating fabric according to any one of claims 1 to 3, wherein the heat insulating portion is formed from a heat insulating composition comprising the aerogel particles, a urethane resin binder, a carbodiimide compound, and an isocyanate compound.

5. The fabric is a heat-insulating fabric according to any one of claims 1 to 4, wherein the fabric has polyester fibers.

6. The fabric is a heat-insulating fabric according to any one of claims 1 to 5, wherein the fabric is water-repellent.

7. The thermal insulation fabric according to any one of claims 1 to 6, wherein the aerogel particles are silica aerogel particles.

8. The heat insulating fabric according to any one of claims 1 to 7, wherein the heat insulating portion has a plurality of protrusions arranged in a dot-like pattern in a plan view.

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