Heat-insulating fabric

Abstract

This heat-insulating fabric (1) has: a base material (10) having a fabric; and heat-insulating parts (11) having aerogel particles and disposed discontinuously in the plane direction on the surface of the base material (10). The height of the heat-insulating part (11) is 0.1 mm-1 mm, and when the area of the surface of the base material (10) is 100%, the total area of the surface of the base material (10) covered by the heat-insulating parts (11) is 8%-65%.

Description

Heat-insulating fabric

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

[0002] Utilizing the high heat insulation property of aerogels, various heat insulation materials have been developed. For example, Patent Documents 1 and 2 describe a heat insulation material produced by applying a paint in which silica aerogel is dispersed in a binder solution to the entire surface of a substrate and drying it.

[0003] Japanese Patent Application Laid-Open No. 2020-29528 International Publication No. 2022 / 259930 Patent No. 6584046 Utility Model Registration No. 3233325

[0004] Heat insulation materials using silica aerogel are used not only in the automotive, housing, and home appliance fields, but also in clothing and the like having high heat retention properties in the apparel field as described in Patent Documents 3 and 4, for example. For fabric for clothing, it is desirable to have moisture permeability from the viewpoint of reducing stuffiness and flexibility from the viewpoint of reducing roughness during wearing. However, since silica aerogel and binders are poor in moisture permeability, forming a silica aerogel layer on the entire surface of a substrate such as cloth improves heat retention but reduces moisture permeability. In addition, since silica aerogel is hard inorganic particles, flexibility also decreases.

[0005] In this regard, Patent Document 3 describes a laminated fabric for high heat retention clothing articles including a mixed layer of aerogel and synthetic resin foam, and in paragraph

[0026] , it is described that when a mixture of aerogel and synthetic resin foam is arranged in a spotted or dot pattern, air permeability can be enhanced. However, moisture permeability, which is the property of allowing water vapor to pass through, is different from air permeability, which is the property of allowing air to pass through. Also, in Patent Document 3, from the viewpoints of moisture permeability, flexibility, and heat insulation, no examination has been made regarding the size, arrangement form, etc. of the mixture.

[0006] The present disclosure has been made in view of such a situation, and an object thereof is to provide a heat-insulating fabric excellent in heat insulation, moisture permeability, 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, and a heat insulating portion having aerogel particles and being discontinuously arranged on the surface of the base material in the planar direction, wherein the height of the heat insulating portion is 0.1 mm or more and 1 mm or less, and when the surface area of ​​the base material is taken as 100%, the total area of ​​the surface of the base material covered by the heat insulating portion is 8% or more and 65% or less.

[0008] The heat-insulating fabric of this disclosure has heat-insulating portions that are discontinuously arranged in the planar direction on the surface of the base material. Instead of forming the heat-insulating portions, which contain aerogel particles with poor moisture permeability, continuously across the entire surface of the base material (so-called solid coating), they are formed discontinuously with gaps (spaces) in the planar direction, which allows water vapor to pass through more easily, thus imparting moisture permeability to the heat-insulating fabric. In addition, because the heat-insulating portions, which contain relatively hard aerogel particles, are not continuous, the flexibility of the heat-insulating fabric is improved. Furthermore, as a result of repeated studies by the inventors, it was found that increasing the height of the heat-insulating portions significantly improves the heat-insulating effect. Based on this finding, in the heat-insulating fabric of this disclosure, the height of the heat-insulating portions is specified to be between 0.1 mm and 1 mm. By setting the total area of ​​the base material surface covered by the heat-insulating portions to be between 8% and 65%, moisture permeability and flexibility are achieved while maintaining the desired heat-insulating performance. Thus, the heat-insulating fabric of this disclosure is excellent in heat-insulating performance, moisture permeability, and flexibility. Furthermore, the heat-insulating fabric of this disclosure allows for a reduction in the amount of aerogel used compared to the case where the heat-insulating portion is formed on the entire surface of the base material, thereby enabling lower costs and lighter weight of the heat-insulating fabric.

[0009] (2) In the above configuration, the heat insulating portion may have a plurality of protrusions arranged in a dot-like manner on the surface of the base material. By arranging the heat insulating portion in the form of protrusions in a dot-like manner, in other words, by scattering them in an island-like manner, it is easier to evenly distribute the heat insulating portion in the planar direction of the base material, and the distance between adjacent protrusions can be made relatively large. This improves moisture permeability and flexibility.

[0010] (3) In the configuration of (2) above, the aspect ratio of the protrusions, which is the ratio of the height to the maximum distance from the bottom surface, may be set to 0.01 or more and 0.23 or less. As mentioned above, according to the inventors' knowledge, from the viewpoint of improving heat insulation, a larger height of the heat insulating portion is desirable. However, when the heat insulating portion is arranged in a dot shape in the form of protrusions, each protrusion is fixed independently to the base material, so if the height of the protrusions is large, they are more likely to fall off due to washing, etc. With this configuration, by specifying the aspect ratio of the protrusions to 0.01 or more and 0.23 or less, the desired durability against washing (washability) can be achieved.

[0011] (4) In the configuration of (2) or (3) above, the protrusion may be configured to be hemispherical. By making the protrusion a rounded shape without corners, the impact received during washing is reduced, and the protrusion is less likely to fall off. Therefore, 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 heat insulating portion may be formed from a heat insulating portion composition having 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, and the aerogel particles are less likely to fall off (shed powder) 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, thereby improving the adhesion of the heat insulating portion to the substrate. This makes the heat insulating portion less likely to peel off even after washing. Thus, this configuration improves the washability of the heat insulating fabric.

[0015] (8) In any of the above configurations, a protective layer may be further laminated on the outside of the insulating portion. With this configuration, the insulating portion is placed between the base material and the protective layer, making it less likely to fall off due to friction during use or impact during washing. This improves durability and washability. In addition, since the space (air layer) between the insulating portion is sealed by the base material and the protective layer, the insulating effect of the air layer is also exerted in addition to the insulating effect of the insulating portion, improving the insulation performance.

[0016] (9) 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 silica aerogel particles, both on the outer surface and the interior (pore-forming surface), water penetration is suppressed, which is suitable for improving washability.

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

[0018] This is a top view of one embodiment of the thermal insulation fabric of the present disclosure. This is a cross-sectional view taken in the direction of II-II in Figure 1.

[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 of Figure 1. As shown in Figures 1 and 2, the thermal insulation fabric 1 comprises a base material 10 and a thermal insulation portion 11. The base material 10 is a woven fabric made of 100% 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] 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 and thermal insulation portions arranged discontinuously in the planar direction on the surface of the base material.

[0023] [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.

[0024] 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.

[0025] 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.

[0026] [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."

[0027] 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.

[0028] The shape of aerogel particles is not particularly limited, and can be spherical, irregularly shaped, or in any other form. When aerogel particles are spherical or chamfered (rounded), they are more easily fixed by the binder, making them less likely to fall off, and reducing the gaps between particles, thus increasing the filling capacity. In this specification, "spherical" is not limited to a perfectly spherical shape, but includes shapes close to spherical (almost spherical). For example, chamfered particles can be easily obtained by grinding aerogel powder. Considering the ease of coating the insulating composition for forming the insulating part and the suppression of aerogel particle fall-off, 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.

[0029] The insulating portion is arranged discontinuously in the planar direction on the surface of the substrate. The form of the insulating portion is not particularly limited; for example, it may be a form in which multiple protrusions are scattered in a dot-like, i.e., island-like manner, or a form in which multiple protrusions are arranged spaced apart from each other, or a form in which the protrusions intersect and are arranged in a grid pattern. When the insulating portion is composed of multiple elements such as protrusions or other protrusions, the shape and size of the individual elements may be the same or different. The multiple elements may be arranged evenly in the planar direction, or they may be arranged to create a sparse or dense arrangement in the planar direction by changing the distance (pitch) between adjacent elements.

[0030] The height of the insulation layer should be between 0.1 mm and 1 mm. From the perspective of improving insulation performance, it is good to make it 0.15 mm or more, or even 0.20 mm or more. If thinness or flexibility is required, it is good to make it 0.85 mm or less, or even 0.50 mm or less.

[0031] When the insulation 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 suppressing the detachment of the protrusions, it is preferable that the top of the protrusions have a curved shape, such as a semi-circular cross-section.

[0032] 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 suppressing the detachment of the protrusion, 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.

[0033] The aspect ratio, calculated by dividing the height of the protrusion by the maximum distance from the base, should preferably be 0.01 or greater from the viewpoint of thermal insulation. A value of 0.02 or greater is even more preferable. Furthermore, from the viewpoint of suppressing the detachment of the protrusion and improving washability, it is desirable to have a value of 0.23 or less. A value of 0.20 or less is even more preferable.

[0034] When the surface area of ​​the base material is considered as 100%, the total area of ​​the base material surface covered by the insulating layer (the area of ​​the base material surface covered by the insulating layer) should be between 8% and 65%. Even if the area where the insulating layer is formed is relatively small, the insulating performance does not easily decrease because an air layer exists in the gaps of the insulating layer. From the perspective of improving insulating performance, it is good to make it 10% or more, and even 20% or more. From the perspective of improving moisture permeability and flexibility, it is good to make it 60% or less, and even 50% or less.

[0035] [Other Elements] The thermal insulation fabric of this disclosure only needs to have a base material and an insulating portion, and is not particularly limited to other components. For example, the thermal insulation fabric of this disclosure may have a protective layer laminated on the outside of the insulating portion (on the side opposite to the base material in the thickness direction). By covering the insulating portion with a protective layer, the insulating portion becomes less likely to fall off due to friction during use or impact during washing. This improves durability and washability. In addition, since the space (air layer) between the insulating portions is sealed by the base material and the protective layer, the insulating effect of the air layer is also exerted in addition to the insulating effect of the insulating portion, improving thermal insulation.

[0036] The form of the protective layer is not particularly limited and can be woven, knitted, nonwoven, film, or sheet. Examples include woven fabrics, knitted fabrics, nonwoven fabrics, 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. The protective layer may consist of a single layer or be a laminate in which the same material or different materials are laminated in two or more layers. Examples of laminates include aluminum vapor-deposited films.

[0037] <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, and then drying it. The components other than aerogel particles in the thermal insulation composition are not particularly limited, but considering durability and other factors, a form containing a urethane resin binder, a carbodiimide compound, and an isocyanate compound is desirable.

[0038] 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.

[0039] 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.

[0040] From the viewpoint of increasing the crosslinking density of the binder and thereby increasing the retention force of aerogel particles, the content of the carbodiimide compound should be 1 part by mass or more per 100 parts by mass of the urethane resin binder. 2 parts by mass or more is preferable. On the other hand, from the viewpoint of thermal insulation, it is desirable to have a low content of compounds that do not contribute to improving thermal insulation. Therefore, the content of the carbodiimide compound should be 10 parts by mass or less per 100 parts by mass of the urethane resin binder. 8 parts by mass or less is preferable.

[0041] Examples of isocyanate compounds include aromatic diisocyanate compounds, aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, and mixtures thereof. Specifically, examples include 4,4'-dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), 2,4,6-triisopropylphenyl diisocyanate (TIDI), 4,4'-diphenylmethane diisocyanate (MDI), and tolylene diisocyanate (TDI).

[0042] From the perspective of improving the adhesion of the heat-insulating 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 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 less. 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 preferable.

[0043] In addition to the aerogel particles, urethane resin binder, carbodiimide compound, and isocyanate compound, the heat-insulating part composition may also contain a coupling agent, a dispersant, a flame retardant, etc. 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 holding force of the aerogel particles can be increased. The content of the coupling agent is preferably 0.1 part by mass or more per 100 parts by mass of the urethane resin binder in order to exert its effect. On the other hand, from the perspective of heat insulation, the content of the coupling agent is preferably 3 parts by mass or less.

[0044] For example, silica aerogel particles have a low 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 compatible with water. Therefore, when preparing the heat-insulating part composition using water as a solvent, it is desirable to blend a dispersant to improve the dispersibility of the silica aerogel particles. Examples of the dispersant include surfactants and thickeners.

[0045] As surfactants, there are ionic surfactants (cationic surfactants, anionic surfactants, amphoteric surfactants) and non-ionic surfactants. Examples of 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 non-ionic surfactants include special polycarboxylic acid amine salts, polyethylene oxide (PEO), polyvinyl alcohol (PVA), etc. It is also preferable to use a combination of non-ionic surfactants and ionic surfactants.

[0046] When a flame retardant is blended, the heat insulation part can be imparted with flame retardancy. Known flame retardants such as halogen-based, phosphorus-based, and metal hydroxide-based ones can be used. Considering the environmental load, it is desirable to use a phosphorus-based flame retardant. Examples of phosphorus-based flame retardants include ammonium polyphosphate, red phosphorus, phosphate esters, etc. Among them, those coated with water-insoluble substances or water-resistant resins are desirable because the flame retardant is difficult to flow out even when it comes into contact with moisture during use. For example, ammonium polyphosphate, ammonium polyphosphate coated with resin, are suitable.

[0047] The composition for the heat insulation part may be prepared by blending, for example, aerogel powder, urethane resin binder, carbodiimide compound, isocyanate compound, and other components added as required, and stirring. If the urethane resin binder does not contain water, water may be added appropriately for preparation. When the aerogel is silica aerogel, considering its dispersibility, it is desirable to add a dispersant to the urethane resin binder or a liquid obtained by adding the urethane resin binder to water, and then add the silica aerogel powder. Stirring may be done with blade stirring, but shear force or ultrasonic waves may also be actively applied. A planetary mixer or a media-type mixer may also be used.

[0048] The heat-insulating composition can be applied to the substrate using coating machines such as screen printing, rotary screens, blade coaters, bar coaters, die coaters, comma coaters (registered trademark), and roll coaters, or by brushing or spraying. After application, 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.

[0049] Next, the present disclosure will be described in more detail with reference to examples.

[0050] <Sample Preparation> [Examples 1-4] First, the heat insulating composition (in parts by mass) shown in Table 1 below was prepared as follows: A urethane resin emulsion as a urethane resin binder (Sanyo Chemical Industries, Ltd.'s "Permarin® UA-368", 50% solids by mass), a nonionic surfactant as a dispersant (special polycarboxylic acid amine salt, Sanopco Inc.'s "Nopcospers® 6100") and a carboxymethylcellulose sodium salt (CMC-Na, Daiichi Kogyo Seiyaku Co., Ltd.'s "Selogen® BSH-12") were added to water and stirred. Silica aerogel powder (pulverized product of Cabot Corporation's "Aerogel Particles P200", 90% diameter (D ９０ (150 μm), a carbodiimide compound, and an isocyanate compound were added and the mixture was stirred.

[0051] Next, a woven fabric made of 100% polyester fibers (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 becomes water-repellent 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 at a predetermined pitch. In this way, samples of heat-insulating fabrics of Examples 1 to 4 were produced, in which raised areas made of cured heat-insulating composition were arranged in a dot pattern on the surface of the base material. In all samples, the raised areas all have a hemispherical shape with a circular base. The base diameter (base area) and height of the raised areas differ from sample to sample. The size of the raised areas in each sample is the same. Table 1, shown later, shows the height of the protrusions, the base diameter, aspect ratio, pitch (the distance between the centers of adjacent protrusions minus the base radius of two protrusions (= base diameter of one protrusion)), and the coverage area of ​​the substrate surface by the insulating portion for each sample.

[0052] [Comparative Example 1] The heat insulating compositions used in the production of the samples of Examples 1 to 4 were blade-coated onto the surface of a substrate to a thickness of approximately 0.3 mm. This was then placed in a hot air oven and held at 80°C for 1 hour, after which the temperature was raised to 100°C for further drying until no mass loss occurred. In this way, a sample of heat insulating fabric of Comparative Example 1 was produced, in which the cured heat insulating composition was arranged in layers on the surface of the substrate. The coverage area of ​​the substrate surface by the formed aerogel layer was 100%.

[0053] [Comparative Examples 2-4] Samples of heat-insulating fabrics for Comparative Examples 2-4 were manufactured in the same manner as in Examples 1-4, except that the height of the protrusions was set to 0.25 mm and the base diameter and pitch were appropriately changed. The height of the protrusions, base diameter, aspect ratio, pitch, and coverage area of ​​the heat-insulating portion are shown in Table 1 below.

[0054] [Reference Example 1] A sample of the heat-insulating fabric of Reference Example 1 was manufactured in the same manner as in Example 2, except that the height of the protrusions was changed to 0.85 mm and the aspect ratio was changed to 0.24. The height of the protrusions, the diameter of the base, the aspect ratio, the pitch, and the coverage area by the heat-insulating part are shown in Table 1 below.

[0055] <Evaluation Method> [Washability] The manufactured sample was cut into a rectangle measuring 280 mm in length and 210 mm in width, and a washing test was conducted 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 the washing method "C4M" in Annex E of the same JIS, "Specifications for washing method of Type C standard washing machine (pulsator type)", was repeated 10 times. The drying method was Method A (hang drying). The contents of the washing method "C4M" specified in Annex E are as follows: Water temperature: 40 ± 3℃. Indicated water volume in the washing and rinsing process: 40 L. Washing process: Washing time 6 minutes, spin-drying time 3 minutes. First rinsing process: Rinse time 2 minutes, spin-drying time 3 minutes. Second rinsing process: Rinse time 2 minutes, spin-drying time 3 minutes. The mass of the samples was measured before and after the test, and the washability was evaluated based on the mass retention rate calculated using the following formula (I). A mass retention rate of 90% or higher was considered a pass, while a rate below 90% was considered a fail. Mass Retention Rate (%) = Sample Mass After Washing / Sample Mass Before Washing × 100 ... (I)

[0056] [Thermal Insulation (Heat Retention)] The manufactured sample was cut into a 300 mm x 300 mm square, and a heat retention test was conducted 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%. 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 base material side up (opposite side from the constant temperature heating element). A higher heat retention rate indicates better insulation performance. Insulation performance was evaluated as follows: a heat retention rate of 12% or higher was considered a pass, and anything below 12% 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]

[0057] [Moisture Permeability] The manufactured sample was cut into a circular shape with a diameter of 70 mm, and a moisture permeability test was conducted based on "7.1.2 A-1 Method (Calcium Chloride Method)" of JIS L1099:2021 "Test Method for Moisture Permeability of Textile Products". The sample was placed with the insulation side facing upwards (opposite side from the desiccant). The moisture permeability of the sample was then calculated using formula (1) of the same method. A higher moisture permeability indicates higher moisture permeability. Moisture permeability was evaluated as follows: ２ - Pass if h or higher, 300g / m ２ If the value was less than h, the student failed.

[0058] [Flexibility] The manufactured sample was cut into strips 20 mm wide and 150 mm long, and a flexibility test was conducted 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 insulating side facing downwards. In this test, the shorter the distance the sample moved, the higher its flexibility. The flexibility was evaluated as follows: a distance of 60 mm or less was considered a pass, and a distance greater than 60 mm was considered a fail.

[0059] <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.

[0060] As shown in Table 1, the samples of Examples 1 to 4 all exhibited good moisture permeability, flexibility, heat insulation, and washability. Compared to the sample of Example 1, the sample of Example 2, which had a larger height of the protrusions, showed improved heat insulation. In contrast, the sample of Comparative Example 1, in which the heat insulation was formed to cover the entire surface of the substrate rather than forming it in a dot pattern, showed good heat insulation, but both moisture permeability and flexibility decreased. Furthermore, the sample of Comparative Example 2, in which the area covered by the heat insulation was greater than 65%, did not exhibit sufficient moisture permeability or flexibility. Conversely, the samples of Comparative Examples 3 and 4, in which the area covered by the heat insulation was less than 8%, showed good moisture permeability and flexibility, but decreased heat insulation. In addition, the samples of Reference Example 1 and Comparative Example 3 had a ratio of the protrusions greater than 0.23, resulting in good moisture permeability and flexibility, but the desired washability could not be obtained.

[0061] 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.

[0062] 1: Insulating fabric, 10: Base material, 11: Insulating part, 110: Protruding part.

Claims

1. A heat-insulating fabric comprising a base material having a cloth, and a heat-insulating portion having aerogel particles and being discontinuously arranged on the surface of the base material in the planar direction, wherein the height of the heat-insulating portion is 0.1 mm or more and 1 mm or less, and when the surface area of ​​the base material is taken as 100%, the total area of ​​the surface of the base material covered by the heat-insulating portion is 8% or more and 65% or less.

2. The heat insulating fabric according to claim 1, wherein the heat insulating portion has a plurality of protrusions arranged in a dot-like pattern on the surface of the base material.

3. The heat insulating fabric according to claim 2, wherein the aspect ratio of the protrusion, which is the ratio of the height to the maximum distance of the bottom surface, is 0.01 or more and 0.23 or less.

4. The heat insulating fabric according to claim 2 or claim 3, wherein the convex portion is hemispherical.

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 heat insulating fabric according to any one of claims 1 to 6, 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.

8. The heat insulating fabric according to any one of claims 1 to 7, further comprising a protective layer laminated on the outside of the heat insulating portion.

9. The thermal insulation fabric according to any one of claims 1 to 8, wherein the aerogel particles are silica aerogel particles.

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