JP2024077807A - Thermal barrier tent membrane structure with excellent weather resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building structure equipped with a thermal barrier tent membrane excellent in weatherability (reduction of ultraviolet degradation) and mildew resistance (algae resistance) in order to maintain appearance and basic performance, and to contribute to global environmental conservation by reducing waste by lowering the frequency of disposal (replacement) by extending the service life of the thermal barrier tent membrane.

SOLUTION: In a composite sheet in which a thermoplastic resin layer is laminated on a fabric, the thermoplastic resin layer requires surface-treated titanium oxide particles (the primary average particle diameter is 0.4-1.2 μm), a keto/enol type tautomer, and a mildew resistance (algae resistance) agent as essential ingredients, thereby extending the service life, and further, a structure containing zinc oxide or a mixture of titanium oxide and zinc oxide is provided in the thermoplastic resin layer, and a thin film layer containing "keto/enol type tautomer and N-OR type hindered amines" or "zinc oxide or a mixture of titanium oxide and zinc oxide" or a photocatalytic metal oxide is provided on the thermoplastic resin layer.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates primarily to a tent membrane structure that has heat insulation properties and can withstand long-term use, i.e., a heat-shielding tent membrane structure with an extended service life; specifically, to an architectural structure equipped with a heat-shielding tent membrane whose service life has been extended by preventing discoloration due to sunlight over time, preventing deterioration due to sunlight, and preventing the growth of mold and algae in order to maintain its appearance.

Enclosed tent membrane structures are classified into those that are primarily intended for entertainment (people), such as indoor sports (tennis, futsal, bouldering, etc.), event halls, pavilions, traveling circus tents, video projection domes, and glamping, and those that are primarily intended for storage and stockpiling of factory materials and product logistics (goods), such as tent warehouses. All of them use synthetic fiber fabrics such as polyester fiber fabrics as the base material, and tarpaulins or waterproof canvases that are covered on both sides with thermoplastic resin layers such as soft polyvinyl chloride resin. Enclosed tent membrane structures have entrance doors and opening/closing windows that form an enclosed space when closed, while open types are open-ceiling structures that are primarily intended for roof structures, such as sunshade monuments in parks and theme parks, garden terrace roofs installed in spaces between buildings, and pergola shades. Enclosed tent membrane structures protect people and goods from wind, rain, and sunlight, but have the disadvantage that they are semi-transparent to allow natural lighting, which means that solar heat tends to build up inside in the summer. On the other hand, while open-type warehouses are well ventilated, they are inadequate for protecting people and goods from the elements. In particular, closed-type tent membrane structures that are primarily used for entertainment (people) are equipped with air conditioning and heating/cooling equipment, but tent warehouses that are primarily used for logistics (goods) are rarely equipped with such equipment. However, the heat builds up inside tent warehouses in the summer, making them harsh environments, so for those who manage and take in and out the storage and stockpiling of factory materials, heatstroke prevention measures such as electric fans and spot coolers are essential.

In order to reduce the heat inside such a tent warehouse, it is effective to make the tent membrane (tarpaulin, waterproof canvas) a reflective color such as white or silver. In particular, it is known that titanium oxide pigments have a high refractive index and therefore a high light scattering power, which results in a high solar reflectance (heat shielding rate). However, the greater the light scattering power, the higher the concealment power becomes, and the light gathering ability of the tent membrane is hindered, so that the inside of the tent warehouse becomes an environment where lighting is required even during the day. In response to this dilemma, the applicant previously proposed a membrane material (Patent Document 1) for a tent (warehouse) that combines a heat shielding effect and light gathering ability, in which 0.3 to 30 mass% of amorphous inorganic compound particles (titanium oxide) with a refractive index of 1.8 or more, a particle size distribution of 0.3 to 3.0 μm, and an aspect ratio of 1.0 to 3.0 are contained in the thermoplastic resin coating layer of the membrane material. In this embodiment, a heat shielding rate of 38 to 65% and a light gathering ability of 4 to 45% can be obtained, and it is expected that the effect of reducing the power consumption of air conditioning in the summer and the power consumption of lighting throughout the year can be expected. However, the price of natural lighting with a light transmittance of 4-45% is that the UV damage caused by light transmission can cause the tent membrane (thermoplastic resin coating layer) to discolor, or cause cracks on the surface, shortening the membrane's service life. As part of the recent SDGs efforts, there is a demand for tent membrane materials that can be used for a long time. This is because extending the service life of tent membrane materials by several years can lengthen the replacement cycle, reduce consumption of petrochemical resources that are the raw materials for synthetic fiber fabrics and thermoplastic resins used to manufacture tent membrane materials, and contribute to society by reducing carbon dioxide emissions.

Specifically, as a means for improving the service life of a tent (warehouse) membrane material made of soft polyvinyl chloride resin, the applicant has proposed a method of blending an ultraviolet absorber into a soft polyvinyl chloride resin layer (Patent Document 2), a method of providing a coating layer blended with a high molecular weight ultraviolet absorber on the surface of a heat-shielding composite sheet (Patent Document 3), and a light-gathering heat-shielding membrane material having a photocatalytic outermost layer (Patent Document 4) as an outdoor membrane material that prevents soot-dust stains that reduce the heat-shielding effect for a long period of time and has excellent light-gathering, heat-shielding, and stain removal properties. In addition, as a membrane material that can prevent environmental stains such as soot-dust stains and discoloration due to mold for a long period of time, the applicant has proposed a mold inhibitor containing an inorganic mold-proofing substance as the main component, and an aesthetically sustaining laminated membrane material with a photocatalytic outermost layer (Patent Document 5). All of these have useful effects, but as one of the recent efforts toward the SDGs, there is a demand for architectural structures equipped with heat-shielding tent membranes that can be used for a long period of time, and there is an urgent need to find a technical solution to extend the service life of such structures.

JP 2007-055177 A Japanese Patent Application Laid-Open No. 59-41249 JP 2001-225423 A JP 2003-251728 A JP 2003-053905 A

The problem to be solved by this invention is to improve the service life of heat-shielding tent membrane structures, that is, to provide architectural structures equipped with heat-shielding tent membranes that have excellent weather resistance (reduction of UV degradation) and mold (algae) resistance in order to maintain the appearance and basic performance. In addition, the object of this invention is to contribute to the conservation of the global environment by extending the service life of heat-shielding tent membrane structures, thereby reducing the frequency of disposal (i.e. replacement) and reducing waste.

After considering these points and carrying out repeated studies, the inventors have come to the conclusion that the heat-shielding tent membrane structure of the present invention, which has excellent weather resistance, is a tent membrane structure in which a waterproof sheet is attached to the outer periphery of the side walls of a frame structure that constitutes a space, and to the canopy, and the waterproof sheet is a connected and sewn product of multiple flexible laminates having a configuration of "(surface) thermoplastic resin layer/fabric/(back) thermoplastic resin layer", and at least the (surface) thermoplastic resin layer is essentially made of surface-treated titanium oxide particles with a primary average particle size of 0.4 to 1.2 μm, a keto/enol type tautomer, and an anti-fungal (algae) agent, thereby obtaining an architectural structure equipped with a heat-shielding tent membrane with excellent weather resistance (reduction of ultraviolet degradation) and anti-fungal (algae) properties, and making it possible to improve the service life of the heat-shielding tent membrane structure. As a result, the frequency of disposal (i.e. replacement) of the heat-shielding tent membrane (waterproof sheet) is reduced, and at the same time, the production volume of the membrane material is reduced, thereby reducing the consumption of petrochemical resources that cause carbon dioxide emissions, and contributing to the conservation of a sustainable global environment. This led to the completion of the present invention with the conviction that this will contribute to the conservation of a sustainable global environment.

In the heat-shielding tent membrane structure of the present invention, the keto/enol tautomer is preferably one or more selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers. This keto/enol tautomer repeats mutual conversion between the enol isomer and the keto isomer in nanosecond units when stimulated by sunlight (ultraviolet rays), so that the enol and keto isomers coexist in equilibrium within the thermoplastic resin layer, and the ultraviolet energy received is converted into thermal energy of molecular vibrations during the mutual conversion and released outside the system. This energy attenuation effect reduces damage caused by ultraviolet rays, thereby improving the durability of the heat-shielding tent membrane (waterproof sheet).

In the heat-shielding tent membrane structure of the present invention, the thermoplastic resin layer further contains zinc oxide or a mixture of titanium oxide and zinc oxide, and the zinc oxide and titanium oxide have a coating layer on the particle surface and have a primary average particle diameter of 0.3 μm or less. This allows zinc oxide or zinc oxide and titanium oxide particles with a primary average particle diameter of 0.3 μm or less (0.1 μm to 0.3 μm) to enter the gaps between the surface-treated titanium oxide particles with a primary average particle diameter of 0.4 to 1.2 μm contained in the thermoplastic resin layer, and the zinc oxide and titanium oxide particles with this particle diameter can scatter ultraviolet rays that penetrate into the thermoplastic resin layer and block the transmission of ultraviolet rays. In particular, zinc oxide has an excellent blocking effect against UVA (ultraviolet A rays), and titanium oxide has an excellent blocking effect against UVB (ultraviolet B rays). Therefore, by using a mixture of titanium oxide and zinc oxide, the durability of the heat-shielding tent membrane (waterproof sheet) is improved. The zinc oxide and titanium oxide particles used in the present invention are ultraviolet blocking agents that do not deteriorate the thermoplastic resin layer whose photocatalytic activity has been sealed by surface treatment.

In the heat-shielding tent membrane structure of the present invention, it is preferable that a thin film layer containing one or more keto/enol tautomers selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers, and N-OR hindered amines is formed on the (surface) thermoplastic resin layer. This keto/enol tautomer repeats mutual conversion between the enol isomer and the keto isomer in nanosecond units when stimulated by sunlight (ultraviolet rays), so that the enol and keto isomers coexist in equilibrium within the thin film layer, and the ultraviolet energy received is converted into thermal energy of molecular vibrations during the mutual conversion and released outside the system, thereby reducing damage to the (surface) thermoplastic resin layer caused by ultraviolet rays through the manifestation of an energy attenuation effect. N-OR hindered amine compounds capture peroxide radicals (ROO.) generated by UV damage in the N-OR moiety, neutralize them into alcohols and ketones, and release them. They then transform into nitroxy radicals (N-O.), capture alkyl radicals (R.) generated by UV damage, and the N-OR hindered amine compound returns to its original state. This cycle repeats in nanoseconds, preventing the chain reaction of bond cleavage in the thin film layer caused by the attack of harmful radicals, thereby improving the durability of heat-shielding tent membranes (waterproof sheets).

In the heat-shielding tent membrane structure of the present invention, a thin film layer containing zinc oxide or a mixture of titanium oxide and zinc oxide is formed on the (surface) thermoplastic resin layer, and the zinc oxide and titanium oxide preferably have a primary average particle size of 10 to 50 nm and a coating layer on the particle surface. Due to the presence of this thin film layer, ultraviolet rays penetrating the (surface) thermoplastic resin layer are scattered by the zinc oxide and/or titanium oxide particles having a primary average particle size of 10 to 50 nm, blocking the transmission of ultraviolet rays, and the light resistance of the (surface) thermoplastic resin layer can be further improved by a synergistic effect with the keto/enol tautomer. In particular, zinc oxide has an excellent UVA (ultraviolet A wave) blocking effect, and titanium oxide has an excellent UVB (ultraviolet B wave) blocking effect, so it is preferable to use a mixture of titanium oxide and zinc oxide, thereby improving the durability of the heat-shielding tent membrane (waterproof sheet). The zinc oxide and titanium oxide particles used in the present invention do not deteriorate the thermoplastic resin layer in which the photocatalytic activity is sealed by surface treatment.

In the heat-shielding tent film structure having excellent weather resistance of the present invention, a thin film layer mainly composed of an organosilicate compound or a sol-gel condensate of a silanol group-containing organic silane compound is formed on the (surface) thermoplastic resin layer, and it is preferable that the thin film layer contains one or more photocatalytic metal oxides selected from titanium oxide, titanium peroxide, zinc oxide, tin oxide, strontium titanate, tungsten oxide, bismuth oxide, and iron oxide. By disposing such a thin film layer on the (surface) thermoplastic resin layer, the photocatalytic metal oxide contained in the thin film layer exhibits photocatalytic activity by ultraviolet excitation. This photocatalytic activity contributes to the long-term durability of the thermoplastic resin layer by acting as a self-cleaning action to remove attached foreign matter such as soot and dust stains. At this time, the ultraviolet light received by the heat-shielding tent film structure having excellent weather resistance of the present invention penetrates the thin film layer and reaches the thermoplastic resin layer, but in the thin film layer, a part of the ultraviolet energy that penetrates is consumed by the activation of the photocatalytic metal oxide, so that the ultraviolet energy that reaches the (surface) thermoplastic resin layer located below is attenuated. Therefore, placing a thin film layer on the (surface) thermoplastic resin layer protects the thermoplastic resin layer, which in turn contributes to extending the service life of the weather-resistant heat-shielding tent membrane structure.

The present invention makes it possible to obtain a heat-shielding tent membrane structure with improved durability. In other words, it is possible to provide a heat-shielding tent membrane structure that can maintain a clean appearance for a long period of time due to its excellent weather resistance (reduction of ultraviolet degradation) and mold resistance (algae). Specifically, it is ideal for long-term (10 to 15 years) tent structures such as indoor sports facilities, event pavilions, traveling circuses, planetariums, and tent warehouses, and can also be deployed for applications lasting less than 10 years, such as architectural protection (soundproofing) sheets, pergola shades (membrane ceilings), facade sheets, lift-up sheet shutters, partition sheets, truck hoods, outdoor waterproof sheets, and roofed tents. In particular, the extension of the durability of the heat-shielding tent membrane reduces the frequency of disposal (i.e. replacement), and at the same time, the production volume of membrane material is reduced, which reduces the consumption of petrochemical resources that cause carbon dioxide emissions and contributes to the conservation of a sustainable global environment.

The heat-shielding tent membrane structure of the present invention, which has excellent weather resistance (hereinafter referred to as the "heat-shielding tent membrane structure"), is a tent membrane structure in which a waterproof sheet is attached to the outer periphery of the side walls of a frame structure that constitutes a space, and to the canopy, and the waterproof sheet is a connected and sewn product of multiple flexible laminates having a "(surface) thermoplastic resin layer/fabric/(back) thermoplastic resin layer" configuration, and at least the (surface) thermoplastic resin layer contains surface-treated titanium oxide particles having a primary average particle size of 0.4 to 1.2 μm, a keto/enol type tautomer, and an anti-fungal (algae) agent as essential components, and the thermoplastic resin layer further contains a specific zinc oxide, or a mixture of a specific titanium oxide and a specific zinc oxide. The above includes an embodiment in which a thin film layer containing a keto/enol tautomer and an N-OR hindered amine is formed on a (surface) thermoplastic resin layer, an embodiment in which a thin film layer containing a specific zinc oxide or a mixture of a specific titanium oxide and a specific zinc oxide is formed on a (surface) thermoplastic resin layer, and an embodiment in which a thin film layer mainly made of a sol-gel condensate is formed on a (surface) thermoplastic resin layer, and a photocatalytic metal oxide is contained in this thin film layer. Depending on the solar radiation conditions, location conditions, shape of the tent membrane structure, etc., it is possible to overcome unfavorable conditions by using multiple of these embodiments in one heat-shielding tent membrane structure to share the functions.

The waterproof sheet, which is a part of the heat-shielding tent membrane structure of the present invention, is an extension of multiple flexible laminates (tarpaulin or waterproof canvas) consisting of a "(surface) thermoplastic resin layer/fabric/(back) thermoplastic resin layer" structure, which are connected together. The thermoplastic resin that constitutes the (surface and back) thermoplastic resin layers is a thermoplastic resin or elastomer with a Shore A hardness of about 35 to 85, such as soft polyvinyl chloride resin (mixed with plasticizer), vinyl chloride copolymer resin, chlorinated polyvinyl chloride resin, olefin resin (PE, PP), olefin copolymer resin, ethylene-vinyl acetate copolymer resin (EVA), ethylene-(meth)acrylic acid (ester) copolymer resin, urethane resin, vinyl acetate copolymer resin, styrene copolymer resin, polyester copolymer resin, or fluorine-containing copolymer resin. Two or more of these may be blended in a compatible or semi-compatible state, or two or more may be used as a multi-layer film or multi-layer coating. An elastomer is a block copolymer resin consisting of two or more monomers, and is a flexible resin in which each block component constitutes a hard segment and a soft segment. Tarpaulin for tent membrane structures is a flexible laminate with a thickness of 0.5 to 1.5 mm, in which a thermoplastic resin composition film is laminated on both sides of a fabric as a thermoplastic resin layer (front and back), and the thermoplastic resin composition film is most preferably made of soft polyvinyl chloride resin (mixed with plasticizer), which has excellent processability, flexibility, abrasion resistance, weather resistance, and flame resistance. Waterproof canvas for tent membrane structures is a flexible laminate with a thickness of 0.3 to 0.8 mm, in which a liquid thermoplastic resin composition is impregnated and coated on both sides of a fabric, which is then solidified into a film to form a thermoplastic resin layer (front and back), and the thermoplastic resin composition is most preferably made of soft polyvinyl chloride resin (paste sol mixed with plasticizer), which has excellent processability, flexibility, abrasion resistance, weather resistance, and flame resistance.

The primary average particle diameter of the surface-treated titanium oxide particles contained as an essential component in the thermoplastic resin layer (front surface, or front surface and back surface) is preferably 0.4 to 1.2 μm. Titanium oxide as a white pigment has a particle diameter of 0.2 to 0.4 μm, which is about 1/2 the wavelength of light, to maximize scattering in the visible light region (400 to 700 nm), thereby obtaining high concealment properties. On the other hand, by increasing the particle diameter to 0.4 to 1.2 μm, the concealment properties decrease, but the reflection effect in the near-infrared region (780 to 2500 nm), which accounts for about 50% of solar energy, is increased, thereby obtaining a heat shielding effect superior to that of pigment titanium oxide. The preferred primary average particle diameter is 0.9 to 1.1 μm, and the shape of these surface-treated titanium oxide particles is approximately spherical, egg-shaped, bale-shaped, potato-shaped, etc., with an aspect ratio of 1:1 to 1:2. Surface-treated titanium oxide particles having a minor axis diameter of 0.4 to 0.8 μm, a major axis diameter of 2.0 to 4.0 μm, and an aspect ratio of 1:5 to 1:10, such as rod-shaped or square-shaped particles, can also be used in combination. If the surface treatment is not performed, the photocatalytic activity will cause radical attack on the thermoplastic resin of the thermoplastic resin layer, resulting in deterioration. The surface treatment performed on the titanium oxide particles is for preventing aggregation, improving dispersibility, and sealing the photocatalytic activity of the titanium oxide particles, and is a surface treatment with one or more metal oxides (7 options) selected from aluminum oxide, zirconium oxide, silicon oxide, and aluminum hydroxide. In addition to the surface treatment with these metal oxides, a multi-layer surface treatment may be performed in which a silane coupling agent, saturated alkyl titanate, saturated alkyl silane, polysiloxane, acrylic silicone, and metal soap (metal salt of long-chain fatty acid such as stearic acid or lauric acid and metal such as barium or zinc) are applied in one layer or two layers. Such a surface treatment further improves aggregation prevention and dispersibility. The amount of surface-treated titanium oxide particles contained in the thermoplastic resin layer is 3 to 20 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of the thermoplastic resin.

The amount of the keto/enol tautomer contained as an essential component in the (front surface, or front surface and back surface) thermoplastic resin layer is 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, based on 100 parts by mass of the thermoplastic resin constituting the thermoplastic resin layer, and the keto/enol tautomer is at least one selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers. The use of multiple keto/enol tautomers includes combinations of different systems and variations of combinations in the same system. The keto/enol tautomer is an organic compound that can be reversibly converted between R ₂ -CH-(C═O)-R ₁ (keto isomer) and R ₂ -C═CH(OH)-R ₁ (enol isomer). Benzotriazole tautomers exist in enol and keto forms. The enol isomer (Ia) is an organic compound [Chemical Formula 1] having a skeleton of a C-N bond between one benzene ring (which may have one or two groups selected from a C1-C10 alkyl group, a C4-C10 branched alkyl group, and an alkyl-substituted benzyl group) having hydroxyl groups (1 to 2)/ketone groups (0) and a benzotriazole ring (which may have a chlorine group), specifically a structure having a hydroxyl group at the 2-position of the benzene ring, a structure having hydroxyl groups at the 2-position and any one of the 3-5-positions of the benzene ring, or a structure having a hydroxyl group at the 2-position of the benzene ring and one or two groups selected from an alkyl group, a branched alkyl group, and an alkyl-substituted benzyl group at the 3-position and/or the 5-position. The keto type isomer (IIa) is an organic compound [Chemical formula 2] having a main skeleton of one benzene ring (which may have any of a C1-C10 alkyl group, a C4-C10 branched alkyl group, or an alkyl-substituted benzyl group) having hydroxyl groups (0-1)/ketone groups (1), and a C-N bond between a benzotriazole ring (which may have a chlorine group), specifically a structure having a ketone group at the 2-position of the benzene ring, a structure having a ketone group at the 2-position of the benzene ring and a hydroxyl group at any of the 3-5-positions, or a structure having a ketone group at the 2-position of the benzene ring and an alkyl group, a branched alkyl group, or an alkyl-substituted benzyl group at the 3- and/or 5-positions. Both the keto type and the enol type isomers are repeatedly converted to each other, and both isomers coexist in equilibrium. Benzotriazole compounds having a molecular weight in the range of 250 to 700, particularly hydroxyphenylbenzotriazole derivatives, are preferred as enol types. In the thermoplastic resin layer, the benzotriazole tautomers are repeatedly converted into the enol isomer (Ia) [Chemical formula 1] and the keto isomer (IIa) [Chemical formula 2] by the excitation of solar light (ultraviolet light) energy, and the ultraviolet light energy is converted into molecular vibration energy of the conversion and released outside the system, thereby attenuating the deterioration damage caused by ultraviolet light. The ultraviolet light attenuation effect of the thermoplastic resin layer greatly contributes to the extension of the service life of the heat-shielding tent membrane structure having excellent weather resistance of the present invention. Here, the alkyl-substituted benzyl group means a benzyl group "C ₆ H ₆ -CH ₂ -" substituted with an alkyl group "C ₆ H ₆ -CR ₁ R ₂ -" (R ₁ and R ₂ are C1 to C10 alkyl groups). The benzotriazole tautomers can be used by grafting them to the side chains of acrylic polymers.
R is at least one selected from the group consisting of a hydroxyl group, an alkyl group, a branched alkyl group, and an alkyl-substituted benzyl group.
R is at least one selected from the group consisting of a hydroxyl group, an alkyl group, a branched alkyl group, and an alkyl-substituted benzyl group.

In addition, triazine tautomers exist in enol and keto forms, and the enol isomer (Ib) is an organic compound [Chemical Formula 3] having a main skeleton of a C-C bond between 1 to 3 benzene rings (which may have a C1 to C10 alkyloxy group) having 1 to 2 hydroxyl groups/0 ketone groups and a 1,3,5-triazine ring (which may have an alkyl (1 to 2) substituted phenyl group and/or a hydroxyl (1 to 2) substituted phenyl group), specifically a structure having a hydroxyl group at the 2nd position of the benzene ring, a structure having hydroxyl groups at the 2nd and 4th positions of the benzene ring, a structure having a hydroxyl group at the 2nd position and an alkyloxy group at the 4th position of the benzene ring, an alkyl (1 to 2) substituted phenyl group at the 2nd or 4th position, or a hydroxyl ...2nd and 4th position. The keto type isomer (IIb) is an organic compound [Chemical Formula 4] having a skeleton of a C-C bond between 1 to 3 benzene rings (which may have a C1 to C10 alkyloxy group) having 0 to 1 hydroxyl group/1 ketone group and a 1,3,5-triazine ring (which may have an alkyl (1 to 2) substituted phenyl group and/or a hydroxyl (1 to 2) substituted phenyl group), specifically, a structure having a ketone group at the 2-position of the benzene ring, a structure having a ketone group at the 2-position and a hydroxyl group at the 4-position of the benzene ring, a structure having a ketone group at the 2-position and an alkyloxy group at the 4-position of the benzene ring, the alkyl (1 to 2) substituted phenyl group at the 2-position or the 4-position, or the 2- and 4-positions, and the hydroxyl (1 to 2) substituted phenyl group at the 2-position or the 4-position or the 2- and 4-positions. The keto and enol isomers are repeatedly converted to each other, and the two isomers coexist in an equilibrium state. In particular, triazine compounds having a molecular weight in the range of 250 to 700 are preferred, and as the enol type, hydroxyphenyl-1,3,5-triazine derivatives are particularly preferred. Inside the heat shielding layer, the triazine tautomers are repeatedly converted to the enol isomer (Ib) [Chemical formula 3] and the keto isomer (IIb) [Chemical formula 4] by excitation with solar light (ultraviolet light) energy, and the ultraviolet light energy is converted into molecular vibration energy of the conversion and released outside the system, thereby attenuating the deterioration damage caused by ultraviolet light. The ultraviolet light attenuation effect of the thermoplastic resin layer greatly works to extend the service life of the heat shielding tent membrane structure of the present invention, which has excellent weather resistance. Specifically, the alkyloxy group is a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a tert-butyl group, a pentyloxy group, etc. In addition, the triazine tautomers can be used by grafting them onto the side chains of an acrylic polymer.
R ₁ is a hydroxyl group and/or an alkyloxy group, R ₂ and R ₃ are alkyl-substituted phenyl groups and/or hydroxyl-substituted phenyl groups.
R ₁ is a hydroxyl group and/or an alkyloxy group, R ₂ and R ₃ are alkyl-substituted phenyl groups and/or hydroxyl-substituted phenyl groups.

Diphenyl ketone tautomers exist in enol and keto forms, and the enol isomer (Ic) is an organic compound [Chemical Formula 5] having a main skeleton in which two benzene rings, each having a hydroxyl group (1 to 2), a ketone group (0), and an alkyloxy group (0 to 1), are linked by a C=O bond. Specific examples include a structure having a hydroxyl group at the 2-position of the benzene ring, a structure having hydroxyl groups at the 2- and 4-positions of the benzene ring, and a structure having a hydroxyl group at the 2-position and an alkyloxy group at the 4-position of the benzene ring. Also, the keto-type isomer (IIc) is an organic compound [Chemical Formula 6] having a main skeleton in which one benzene ring (A) having a hydroxyl group (0 to 1 group), a ketone group (1 group), and an alkyloxy group (0 to 1 group) and one benzene ring (B) having a hydroxyl group (1 to 2 groups), a ketone group (0 group), and an alkyloxy group (0 to 1 group) are linked by a C=O bond. Specific examples include a structure having a ketone group at the 2-position of the benzene ring (A), a structure having a ketone group at the 2-position and a hydroxyl group at the 4-position of the benzene ring (A), a structure having a ketone group at the 2-position and an alkyloxy group at the 4-position of the benzene ring (A), a structure having a hydroxyl group at the 2-position of the benzene ring (B), a structure having hydroxyl groups at the 2-position and the 4-position of the benzene ring (B), and a structure having a hydroxyl group at the 2-position and an alkyloxy group at the 4-position of the benzene ring (B). A diphenyl ketone compound having a molecular weight of 200 to 400, in which both the keto and enol isomers are repeatedly converted to each other and coexist in equilibrium, is particularly preferred as an enol type, and a hydroxydiphenyl ketone derivative is preferred. Inside the thermoplastic resin layer, the diphenyl ketone tautomer is repeatedly converted to the enol isomer (Ic) [Chemical formula 5] and the keto isomer (IIc) [Chemical formula 6] by sunlight (ultraviolet light) energy, and the ultraviolet light energy is converted into molecular vibration energy of the conversion and released outside the system, thereby attenuating the deterioration damage caused by ultraviolet light. The ultraviolet light attenuation effect of the thermoplastic resin layer greatly works to extend the service life of the heat-shielding tent membrane structure having excellent weather resistance of the present invention. Specifically, the alkyloxy group is a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a tert-butyl group, a pentyloxy group, etc. In addition, the diphenyl ketone tautomer can be used by grafting it to the side chain of an acrylic polymer.
R ₁ and R ₂ each represent a hydroxyl group and/or an alkyloxy group.
R ₁ and R ₂ each represent a hydroxyl group and/or an alkyloxy group.

The antifungal (algae) agent contained as an essential component in the thermoplastic resin layer is a functional group that exerts an action such as oxidative phosphorylation inhibition, electron transport chain inhibition, -SH group inhibition, DNA synthesis inhibition, cell epidermal function inhibition, lipid metabolism inhibition, chelate formation, etc. on the cell walls, cell membranes, cytoplasm, and cell nuclei of mold, algae, bacteria (gram positive _, gram negative), fungi, etc., such as -Cl, -Br, -F, _{-I ,} -S-, -(S)n-, _-NO2 , _-CF3 , _-SCN , -NCS, _-SCF3 , _-CHI2 , -CH2Cl, _-CCl3 , -SCCl3, -OCCl3, ═CHCCl3, -CI= _CI2 , -CI=CIBr, _-CH2C≡CI , _-OCH2 These are compounds having C≡Cl, =NC(S)S-, -NHCOC≡Cl _, -CO-N( _OCH3 )-, -CO-NR-CO-, _{-NSCC13 , -NSCC12F, -SO2-CH3 , -SO2 - S - CH3 , -SO2C6H4CH3 , -NC6H4} (p- _CH3 ) _SO2C6H4 (p- _CH3 ) _, and _-NC6H4 (p- _CH3 ) _SO2N ( _CH3 ) ₂ groups _. These antifungal (algae) agents include organic compounds such as imidazole compounds, thiazole compounds, N-haloalkylthio compounds, pyridine compounds, pyrithione compounds, isothiazolin compounds, triazine compounds, and organometallic compounds, and it is preferable to use at least one selected from these compounds in an amount of 0.01 to 5 parts by mass, particularly 0.1 to 2.0 parts by mass, per 100 parts by mass of the thermoplastic resin constituting the thermoplastic resin layer. In addition, by using them in combination with inorganic antifungal (algae) agents such as silver ion-supported zeolite and copper ion-supported zeolite, the initial to middle period is mainly the antifungal (algae) effect of the organic compound, and the middle to late period is mainly the effect of the inorganic antifungal (algae) agent, so that the overall aesthetic durability can be extended.

Specific examples of imidazole compounds include 2-(4-thiazolyl)-benzimidazole (abbreviated as TBZ), 2-(carbomethoxyamino)benzimidazole (abbreviated as BCM), and 1-(butylcarbamoyl)-2-benzimidazolecarbamate methyl. Examples of thiazole compounds include 2-n-octyl-4-isothiazolin-3-one, 2-mercaptobenzothiazole, 2-(thiocyanomethylthio)benzothiazole, and 2-(thiocyanomethylsulfonyl)benzothiazole. Examples of N-haloalkylthio compounds include N-(fluorodichloromethylthio)phthalimide, N-trichloromethylthiotetrahydrophthalimide, N-(trichloromethylthio)-4-cyclohexane 1,2-dicarboximide, and N,N-dimethyl-N'-(fluorodimethylthio)-N'-phenylsulfamide. Examples of pyridine compounds include Examples of pyrithione compounds include zinc bis(pyridine-2-thiol-1-oxide) salt (abbreviated as ZPT), sodium (2-pyridinethiol-1-oxide) salt, and 2,2'-dithio-bispyridine-1-oxide. Examples of isothiazoline compounds include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolyl-3-one, and 2-trichloromethylthio-4-isothiazolin-3-one. Examples of triazine compounds include hexahydro-N,N',N"-tris(2-hydroxyethyl)-S-triazine and hexahydro-N,N',N"-triethyl-S-triazine. Examples of organometallic compounds include 10,10'-oxybisphenoxyarsine (abbreviated as OBPA), 8-oxyquinoline copper, and nickel 2-ethylhexanoate. From the standpoint of improving service life, it is particularly preferable to use these anti-mold (algae) agents in the form of inorganic porous microparticles such as silica, zeolite, and diatomaceous earth, or sustained-release types supported in the micropores of cyclodextrin.

As an embodiment of the heat-shielding tent membrane structure of the present invention, the thermoplastic resin layer (on the front surface, or on the front and back surfaces) may further contain zinc oxide or a mixture of titanium oxide and zinc oxide as an ultraviolet shielding material. The zinc oxide and titanium oxide preferably have a primary average particle diameter of 0.3 μm or less and a coating layer on the particle surface. This allows zinc oxide or zinc oxide and titanium oxide particles with a primary average particle diameter of 0.3 μm or less (0.1 μm to 0.3 μm) to enter the gaps between the surface-treated titanium oxide particles with a primary average particle diameter of 0.4 to 4.0 μm contained in the thermoplastic resin layer, and the surface area of the zinc oxide and titanium oxide particles with such particle diameters is increased, scattering ultraviolet rays that penetrate into the thermoplastic resin layer and effectively shielding the transmission of ultraviolet rays. This ultraviolet shielding effect further improves the light resistance of the thermoplastic resin layer through the synergistic effect with the keto/enol tautomer. In particular, zinc oxide has an excellent UVA (ultraviolet A wave) shielding effect, and titanium oxide has an excellent UVB (ultraviolet B wave) shielding effect, so it is preferable to use a mixture of titanium oxide and zinc oxide with a mass ratio of 10:6 to 6:10, and particularly a mixture of 10:10. The zinc oxide and titanium oxide particles used in the present invention are preferably those whose photocatalytic activity has been sealed by surface treatment. If the surface treatment is not performed, the thermoplastic resin of the thermoplastic resin layer will be deteriorated by radical attack due to the photocatalytic activity. The surface treatment performed on the zinc oxide particles and titanium oxide particles is for preventing aggregation, improving dispersibility, and sealing the photocatalytic activity of the titanium oxide particles, and is a surface treatment with one or more metal oxides (7 options) selected from aluminum oxide, zirconium oxide, and silicon oxide. In addition to the surface treatment with these metal oxides, a multi-layer surface treatment may be used in which a single layer of one type or two layers of two types of silane coupling agents, saturated alkyl titanates, saturated alkyl silanes, polysiloxanes, acrylic silicones, and metal soaps (metal salts of long-chain fatty acids such as stearic acid and lauric acid and metals such as barium and zinc) are applied as a further surface treatment. Such surface treatments further improve the prevention of aggregation and dispersibility. The amount of surface-treated zinc oxide and/or surface-treated titanium oxide particles with a primary average particle size of 0.3 μm or less (0.1 μm to 0.3 μm) contained in the thermoplastic resin layer is 3 to 20 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of the thermoplastic resin.

As an embodiment of the heat-shielding tent membrane structure of the present invention, a thin film layer containing one or more keto/enol tautomers selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers, and N-OR hindered amines can be formed on the (surface) thermoplastic resin layer. The amount of keto/enol tautomers contained in the thin film layer is preferably 1 to 25 parts by mass, particularly 3 to 10 parts by mass, per 100 parts by mass of the thermoplastic resin binder of the thin film layer. The amount of N-OR hindered amine contained in the thin film layer is preferably 0.5 to 12 parts by mass, particularly 1 to 6 parts by mass, per 100 parts by mass of the thermoplastic resin binder of the thin film layer. Examples of the thermoplastic resin binder include acrylic resins, urethane resins, fluorine-based copolymer resins, a combination of acrylic resins/urethane resins, and a combination of acrylic resins/fluorine-based copolymer resins. The thickness of the thin film layer is preferably 1 to 20 μm, particularly 3 to 12 μm. The thin film layer can be formed by selecting from known coating methods such as gravure coating, wire bar coating, kiss coating, and clearance coating.

The acrylic resin used as the binder for the thin film layer may be a polymer or copolymer resin made of one or more monomers selected from acrylic acid alkyl esters having an alkyl group with 1 to 18 carbon atoms and methacrylic acid alkyl esters having an alkyl group with 1 to 18 carbon atoms, or may be a copolymer of the above acrylic monomers with ethylenically unsaturated carboxylic acids, amide compounds, epoxy group-containing (meth)acrylic acids, α-olefins, vinyl ethers, alkenyls, vinyl esters, aromatic vinyl compounds, or an acrylic/silicon copolymer resin copolymerized with an organosiloxane. Examples of urethane resins include aromatic polyurethanes (ester, ether, polycarbonate), aliphatic polyurethanes (ester, ether, polycarbonate), and alicyclic polyurethanes (ester, ether, polycarbonate). In terms of light fastness, aliphatic polyurethanes and alicyclic polyurethanes are preferred, and in terms of weather fastness (hydrolysis resistance), ether and polycarbonate urethane resins are particularly preferred. In addition, urethane/silicon-based graft copolymer resins, urethane/fluorine-based graft copolymer resins, etc. can also be used. The fluorine-based copolymer resins include copolymers obtained by copolymerizing two or more fluorine atom-containing monomers such as vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene, and fluoroolefin copolymers obtained by copolymerizing the above-mentioned fluorine atom-containing monomers with vinyl monomers (β-methyl-β-alkyl-substituted-α-olefins, alkyl vinyl ethers, alkyl allyl ethers, vinyl group-containing esters, etc.), which can be used alone or in combination. These are preferably copolymers containing hydroxyl groups and carboxyl groups in the molecular structure that generate crosslinking sites when used in combination with reactive compounds such as isocyanate compounds, aziridine compounds, oxazoline compounds, and carbodiimide compounds. In particular, the isocyanate compound is preferably an aliphatic compound or an alicyclic compound, and examples of the isocyanate compound that can be used include hexamethylene diisocyanate, isophorone diisocyanate, and trimers thereof (isocyanurate type, trimethylpropane type, biuret type), and blocked isocyanates thereof. In addition, the oxazoline compound can be a polymer-type crosslinking agent (emulsion type) having an oxazoline group on the side chain of an acrylic resin (acrylic copolymer resin, acrylic/styrene copolymer resin).

The keto/enol tautomers may be the same as those described in paragraphs [0017] to [0019] of the specification. The N-OR hindered amine compounds have at least one, preferably two, or preferably four, or preferably six hindered amine structures in their molecular structure, and are particularly effective in improving the light resistance of vinyl chloride resins. The N-position of the hindered amine structure shown in the following formula [Chemical Formula 7] has one or more substituents selected from an alkoxy group having 2 to 18 carbon atoms or a cycloalkoxy group having 5 to 12 carbon atoms, and the molecular weight of these is 200 to 400 (one hindered amine structure), 400 to 700 (2 to 3 hindered amine structures), 700 to 1000 (4 to 5 hindered amine structures), or 1000 to 2500 (6 or more hindered amine structures), which are excellent in terms of residual retention in a thin film layer and are therefore preferred.
In the above [Chemical Formula 7], R ₁ , R ₂ , R ₃ and R ₄ are each independently a) a hydrogen atom, b) a straight chain alkyl group or branched alkyl group having 1 to 20 carbon atoms, c) the alkyl group of b) containing one or more -O-, -S-, -SO-, -SO ₂ -, -CO-, -COO-, -OCO-, -CONR-, -NRCO- or -NR-, d) an alkenyl group having 3 to 20 carbon atoms, e) an aryl group having 6 to 10 carbon atoms, f) an aryl group having 1 to 3 substituents selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms and a phenylalkyl group having 7 to 15 carbon atoms, etc., but for the N-OR type hindered amine compound used in the heat-shielding tent membrane structure having excellent weather resistance of the present invention, it is particularly preferable that R ₁ , R ₂ , R ₃ and R ₄ are all hydrogen or all methyl groups. _R5 is i) an alkyl group having 2 to 18 carbon atoms, i.e., one in which the N-position of the hindered amine structure is substituted with an alkoxy group having 2 to 18 carbon atoms, particularly preferably an alkoxy group having 6 to 12 carbon atoms, or ii) a cycloalkyl group having 5 to 12 carbon atoms, i.e., one in which the N-position of the hindered amine structure is substituted with a cycloalkoxy group having 5 to 12 carbon atoms, preferably a cycloalkoxy group having 5, 6 or 8 carbon atoms, particularly preferably a cyclohexyloxy group.

Specific examples of these N-OR type hindered amine compounds are compounds having at least one substituent R ₅ selected from an alkyl group having 2 to 18 carbon atoms or a cycloalkyl group having ₅ to 12 carbon atoms at the N-position of the hindered amine structure [Chemical Formula ₇ ], and these include bis(1-undecaoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, a polycondensate of 4,4'-hexamethylene-bis(N-OR ₅ -2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-tert-octylamino-s-triazine; a polycondensate of 1-(2-hydroxyethyl)-N-OR ₅ -2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid: N,N',N'',N'''-tetrakis[4,6-bis(butyl-(N-OR ₅ -2,2,6,6-tetramethylpiperidin-4-yl)amino)-s-triazin-2-yl]-1,10-diamino-4,7-diazadecane; polycondensate of 4,4'-hexamethylene-bis(N-OR ₅ -2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine; poly[methyl 3-(N-OR ₅ -2,2,6,6-tetramethylpiperidin-4-yloxy)propyl]siloxane; bis(N-OR ₅ -2,2,6,6-tetramethylpiperidin-4-yl)cyclohexylenedioxydimethylmalonate; bis(N-OR ₅ -2,2,6,6-tetramethyl-4-piperidyl)[[3,5bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate; bis(N-OR ₅ -2,2,6,6-tetramethyl-4-piperidyl)sebacate; 1,3,5-tris{N-cyclohexyl-N-[2-(N-OR ₅ -2,2,6,6-tetramethylpiperazin-3-one-4-yl)ethyl]amino-s-triazine; polycondensates of 4,4'-hexamethylene-bis(N-OR ₅ -2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-cyclohexylamino-s-triazine; and poly{N-[4,6-bis(butyl-(N-OR ₅ -2,2,6,6-tetramethylpiperidin-4-yl)amino)-s-triazin-2-yl]-1,4,7-triazanonane}-ω-N''-[4,6-bis(butyl-(N-OR ₅ -2,2,6,6-tetramethylpiperidin-4-yl)amino)-s-triazin-2-yl]amine.

The light stabilization by N-OR type hindered amines begins when the N-OR type hindered amines are oxidized by oxygen, ultraviolet light, peroxides, etc., and converted into nitroxy radicals (NO.), which then capture alkyl radicals (R.) generated by the photodegradation of the thermoplastic resin in the thermoplastic resin layer and convert them into amino ethers (NOR). The N-OR part then captures the peroxide radicals (ROO.) generated by the reaction of the alkyl radicals (R.) with oxygen in the air, which are then detoxified into alcohols and ketones and released, and the N-OR part itself returns to the original nitroxy radical (N-O.). By repeating this cycle in nanoseconds, it is possible to suppress the chain reaction of bond cleavage in the thermoplastic resin caused by the attack of harmful radicals. This radical detoxification cycle is the same for NH type hindered amines and N-alkyl type hindered amines, but N-OR type hindered amines are the most preferable for stabilizing the light resistance of vinyl chloride resins. In the present invention, it is also possible to use an N-OR type hindered amine in combination with an NH type hindered amine, or an N-OR type hindered amine in combination with an N-alkyl type hindered amine, with the combined ratio being 10:1 to 10:10, and particularly 10:2 to 10:5. If the ratio of N-OR type hindered amine used in a blend system mainly composed of vinyl chloride resin is low, a significant improvement in light resistance may not be obtained. In addition, the combined ratio of keto/enol type tautomer and N-OR type hindered amine is preferably 10:1 to 10:5, and particularly 10:3 to 10:4. If the ratio of keto/enol type tautomer used is low, a significant improvement in light resistance may not be obtained.

As an embodiment of the heat-shielding tent membrane structure of the present invention, a thin film layer containing zinc oxide or a mixture of titanium oxide and zinc oxide can be formed on a (surface) thermoplastic resin layer. The zinc oxide and titanium oxide have a primary average particle size of 10 to 50 nm and a coating layer on the particle surface, and the content of zinc oxide or a mixture of titanium oxide and zinc oxide in the thin film layer is preferably 0.1 to 10 mass%, particularly preferably 0.5 to 5 mass%. Such ultrafine zinc oxide and titanium oxide are far from the particle size suitable for white pigments, so that the hiding power is reduced and the thin film layer becomes transparent, and at the same time, the surface area (specific surface area) per unit mass is increased due to the ultrafine particles, so that the UVA (ultraviolet A wave) shielding effect of zinc oxide and the UVB (ultraviolet B wave) shielding effect of titanium oxide are dramatically improved. It is preferable to use ultrafine zinc oxide and ultrafine titanium oxide in a mixture with a mass ratio of 10:6 to 6:10, particularly a mixture with a mass ratio of 10:10. For the same reason, it is preferable that the photocatalytic activity of ultrafine particles of zinc oxide and titanium oxide is blocked by the surface treatment described in paragraph [0016]. The thin film layer is mainly composed of an organosilicate compound or a sol-gel condensate of a silanol group-containing organic silane compound. The organosilicate compound is a tetrafunctional hydrolyzable silane compound represented by the chemical formula Si _n O _n-1 (OR) _{2 (n+1)} , in which R is an alkyl group having 1 to 10 carbon atoms (particularly a lower alkyl group having 1 to 3 carbon atoms) or an aryl group (particularly a phenyl group), and n is the degree of polymerization (n-mer) representing the number of condensed molecules of the tetrafunctional hydrolyzable silane compound and is an integer of 1 or more. Examples of compounds where n is 1 include tetramethoxysilane "Si(OCH ₃ ) ₄ ," tetraethoxysilane "Si(OC ₂ H ₅ ) ₄ ," tetrapropoxysilane "Si(OC ₃ H ₇ ) ₄ ," tetrabutoxysilane "Si(OC ₄ H ₉ ) ₄ ," tetraphenoxysilane "Si(OC ₆ H ₆ ) ₄ ," and dimethoxydiethoxysilane "Si(OCH ₃ ) ₂ (OC ₂ H ₅ ) ₂ ". Compounds with n of 2 or more are polymers formed by condensation of two or more molecules by the reaction between silanol groups formed by hydrolysis of a tetrafunctional hydrolyzable silane compound, and the degree of polymerization represented by n means the number of Si atoms contained in one molecule of the polymer. In the present invention, it is preferable to use a silanol group-containing silane compound obtained by hydrolysis of tetramethoxysilane or tetraethoxysilane with a degree of polymerization of 2 to 10, preferably 4 to 6, since the structure of the sol-gel condensate is finer. The concentration of the hydrolysis product of organosilicate contained in the coating liquid (water/alcohol) forming the thin film layer is preferably in the range of 0.01 to 30% by mass, particularly 0.1 to 5% by mass. In addition, the coating liquid may contain cellulose nanofibers in an amount of 1 to 10% by mass relative to the concentration of the hydrolysis product of organosilicate in order to impart flexibility and bendability to the thin film layer. The cellulose nanofibers used are short fibers having an average aspect ratio (average fiber length/average fiber diameter) of 10 to 50, an average fiber diameter of 3 nm to 100 nm, and an average fiber length of 100 μm or less, particularly 300 nm to 500 nm, and these may be chemically modified with a silane coupling agent, a boric acid compound, a phosphoric acid compound, a silicic acid compound, or the like.

In addition, as an embodiment of the heat-shielding tent film structure of the present invention, a thin film layer mainly composed of an organosilicate compound or a sol-gel condensate of a silanol group-containing organic silane compound can be formed on a (surface) thermoplastic resin layer. This thin film layer preferably contains one or more photocatalytic metal oxides selected from titanium oxide, titanium peroxide, zinc oxide, tin oxide, strontium titanate, tungsten oxide, bismuth oxide, and iron oxide. This photocatalytic metal oxide preferably has an average particle size of 50 nm or less, particularly 20 nm or less, and with this particle size, the specific surface area becomes large and sufficient photocatalytic activity is exhibited, thereby decomposing oily soot and dust stains and allowing self-cleaning removal by rainfall. This allows the heat-shielding effect of the heat-shielding tent film structure of the present invention to be stably maintained for a long period of time. To form this thin film layer, a photocatalytic metal oxide in a sol state is used, and it is preferable to include 10 to 50 mass % of the thin film layer. Metals and metal oxides such as Pt, Rh, _RuO2 , Nb, Cu, Sn, NiO, etc. can be added to these photocatalytic metal oxides as synergistic agents. The ultraviolet light received by the heat-shielding tent film structure of the present invention passes through the thin film layer and then through the thermoplastic resin layer, but in the thin film layer, a part of the ultraviolet energy passing through is consumed for activating the photocatalytic metal oxide, so that the ultraviolet energy reaching the thermoplastic resin layer located below is attenuated. Therefore, disposing the thin film layer on the thermoplastic resin layer protects the thermoplastic resin layer, and thus contributes to extending the service life of the heat-shielding tent film structure. Since the photocatalytic metal oxide has the function of decomposing organic matter by oxidation-reduction due to photocatalytic activity, the thin film layer is mainly composed of an organosilicate compound or a sol-gel condensate of a silanol group-containing organosilane compound, which improves the resistance of the thin film layer to abrasion loads and enables long-term use of the heat-shielding tent film structure. In addition, the thin film layer contains 1 to 10% by mass of a silane coupling agent (aminosilane, vinylsilane, epoxysilane, methacrylsilane, acrylicsilane, chlorosilane, mercaptosilane, isocyanurate silane, isocyanate silane, etc.), and the hydrolyzate of the silane coupling agent is bonded and interposed between the sol-gel condensate and the photocatalytic metal oxide, thereby further improving the bending resistance and resistance to abrasion load of the thin film layer. The thin film layer is 10 nm to 5 μm, and the photocatalytic metal oxide contained in the thin film layer is 10 to 50% by mass, preferably 5 to 35% by mass. In addition, self-cleaning is an effect in which organic residues such as dirt (soot, tar), mold, and algae decomposed by photocatalytic activity are washed away by rainfall, thereby restoring the appearance before the dirt and the like were attached. The thin film layer is mainly composed of the organosilicate compound described in paragraph [0027] or a sol-gel condensate of a silanol group-containing organosilane compound, and may contain 0.1 to 25 mass % of an inorganic colloid (silica sol, antimony sol, alumina sol, zirconia sol, etc.) relative to the concentration of the organosilicate hydrolysis product in order to further extend the abrasion resistance and durability of the thin film layer.

The thermoplastic resin layer of the heat-shielding tent membrane structure of the present invention may contain any additives as necessary. Additives that contribute to improving weather resistance include antioxidants (hindered phenols, phosphites, sulfur, vitamin E, etc.), matting agents such as silica, calcium silicate, magnesium silicate, and aluminum silicate, colorants such as organic pigments, inorganic pigments, aluminum luster pigments, pearl pigments, and dyes, antistatic agents such as surfactants, ionic liquids, conductive carbon, carbon nanotubes, and fullerenes, flame retardants such as sepiolite, montmorillonite, and smectite, abrasion resistance strengthening agents such as isocyanates, acrylates, epoxies, silane coupling agents, and silicone oils, and other antibacterial and antiviral agents. The (front and back) thermoplastic resin layers can be obtained, for example, by melt-rolling (stretching) a soft polyvinyl chloride resin compound to a thickness of 0.1 mm to 1.0 mm using a calendar method or a T-die extrusion method. For example, a soft polyvinyl chloride resin paste sol can be coated or dipped, then heated to gel, forming a film with a thickness of 0.05 mm to 0.5 mm.

The fabric used in the heat-shielding tent membrane structure of the present invention is preferably a woven fabric, and contains one or more types of yarn selected from multifilament yarn, staple spun yarn, and covering yarn, and is either 1) a woven fabric consisting of warp yarn and weft yarn, or 2) a triaxial fabric consisting of warp yarn and upper left/upper right bias yarn, or 3) a quadriaxial fabric consisting of warp yarn, weft yarn, and upper left/upper right bias yarn. In particular, plain weave fabrics made of warp and weft threads, twill fabrics (regular twill weaves such as 2x2, 3x3, and 4x4, and irregular twill weaves such as 3x2, 4x2, 4x3, 5x3, 2x3, 2x4, 3x4, and 3x5), twill fabrics (having a minimum structural unit of at least three warp and weft threads: 3-sheet twill, 4-sheet twill, 5-sheet twill, 6-sheet twill, etc.), satin fabrics (having a minimum structural unit of at least five warp and weft threads: regular twill with 2 jumps, 3 jumps, 4 jumps, 5 jumps, etc.), and other imitation gauze fabrics and twisted fabrics (sha fabrics, ro fabrics) can be used. In particular, when a triaxial or quadriaxial fabric is used, the intersections between the threads are complex and dense, and the network spreads in multiple axial directions, which increases the propagation of external stress such as bending and flapping applied to the weather-resistant heat-shielding tent membrane structure, disperses and deflects the stress over a wide area, mitigating damage and at the same time increasing resistance to external forces such as tearing. The fabric weight is 100 to 500 g/ ^m2 , and the porosity (the total occupancy rate of the space generated by the entanglement of the threads) is preferably about 6 to 25% for tarpaulin and about 0 to 10% for canvas. These fabrics can also be used after known dyeing and finishing processes such as scouring, bleaching, dyeing, softening, water repellency, mildew resistance, flame resistance, and calendaring. Tarpaulin is a fabric laminated with a thermoplastic resin film on both sides, and canvas is a fabric impregnated and coated with a liquid thermoplastic resin composition on both sides, which is then turned into a film.

The yarns constituting the woven fabric (cloth) can be any type of fiber, including synthetic fibers, natural fibers, semi-synthetic fibers, inorganic fibers, and mixed fibers consisting of two or more of these. Generally, however, one or more types of yarns selected from 1) multifilament yarns, 2) staple spun yarns, and 3) and covering yarns made of synthetic fibers such as polypropylene fibers, polyethylene fibers, polyvinyl alcohol fibers, polyester (polyethylene terephthalate: PET, polybutylene terephthalate: PBT, polynaphthalene terephthalate: PNT, etc.) fibers, nylon fibers, and mixed fibers (mixed and twisted) of these fibers can be used. The multifilament yarn may be a long fiber spun bundle (50 to 500 filament bundle) obtained by extruding a thermoplastic resin such as nylon or polyester from a spinneret and spinning the long fiber raw yarn 3 to 5 times, which may be twisted 10 to 200 times/m to obtain a yarn having a fineness of 125 to 2000 denier (139 to 2222 dtex). These multifilament yarns include bulky processed yarns such as taslan yarn and woolly yarn. The short fiber spun yarn is a roving (coarse yarn) obtained by stretching a sliver by opening and kneading a long fiber spun bundle (which may be stretched) obtained by extruding a thermoplastic resin such as nylon or polyester from a spinneret and spinning the long fiber spun bundle (which may be stretched) into a staple of about 3.8 to 5.8 mm in length, which is then drafted and twisted to a predetermined count to obtain a tow spinning. Examples of twisted yarns include single yarns or two single yarns that are aligned and twisted in an S (right) or Z (left) direction, and two-ply yarns that are aligned and twisted in a first twist, each of which is a single yarn or two single yarns that are aligned and twisted in a second direction. The number of twists of these twisted yarns is about 200 to 2000 times/m. Examples of covered yarns include covered yarns in which the short fibers are wrapped around the outer circumference of the multifilament yarn bundle, and in this application, core-sheath composite yarns are also included in the covered yarns.

In particular, special fabrics (woven materials) can be used to improve the tensile breaking strength, tear (cut) strength, explosion-proof pressure resistance, heat resistance, and fire resistance of the heat-shielding tent membrane structure of the present invention. For this fabric, a fabric design mainly made of multifilament yarns such as fluororesin fibers, wholly aromatic polyester fibers, and wholly aromatic polyamide fibers, or a combined design with yarns made of the above-mentioned general-purpose synthetic fibers (insertion of a ripstop structure) is suitable. In addition, for applications as non-combustible materials (non-combustible membrane materials for tent structures) certified by the Minister of Land, Infrastructure, Transport and Tourism, fabrics mainly made of inorganic multifilament yarns such as glass fibers, silica fibers, alumina fibers, silica alumina fibers, carbon fibers, and mixed fibers thereof (mixed and twisted). In particular, in order to dramatically improve the tensile breaking strength, tear (cut) strength, explosion-proof pressure resistance, heat resistance, and fire resistance, it is suitable to design a textile mainly containing yarns (multifilament yarns, staple fiber spun yarns, covered yarns) made of one or more aromatic heterocyclic polymer fibers selected from the group consisting of polybenzimidazole (PBI)-based, polybenzoxazole (PBO)-based, polybenzothiazole (PBT)-based, and copolymers thereof (benzimidazole-benzoxazole copolymers, benzimidazole-benzothiazole copolymers, benzoxazole-benzothiazole copolymers, benzimidazole-benzoxazole-benzothiazole copolymers, and the above copolymers containing an aromatic polyamide component), or to use the textile in combination with yarns made of the above general-purpose fibers (insertion of a ripstop structure). The ripstop structure is, for example, a plain weave fabric having polyester fiber yarns as warp and weft, in which yarns made of aromatic heterocyclic polymer fibers are regularly or randomly arranged at arbitrary positions of the warp and weft, and is suitable for a woven fabric, triaxial fabric, or quadraxial fabric that forms a lattice pattern (or irregular lattice pattern) in appearance. Specifically, in the yarn arrangement 1, 2, 3, 4, 5 ... n (n is an integer) of the warp and weft groups, aromatic heterocyclic polymer fiber yarns are inserted every multiple of 10 (10, 20, 30 ...) to form a lattice pattern. In addition, in a four-axis woven fabric, any or all of the warp, weft, upper left bias yarn, and upper right bias yarn can be aromatic heterocyclic polymer fiber yarns. Specifically, the warp and weft can be aromatic heterocyclic polymer fiber yarns, and the upper left bias yarn and upper right bias yarn can be other fiber yarns, or the upper left bias yarn and upper right bias yarn can be other aromatic heterocyclic polymer fiber yarns, and the warp and weft can be other fiber yarns.

The tarpaulin used in the heat-shielding tent membrane structure of the present invention can be a film (sheet) with a thickness of 0.1 mm to 1.0 mm, particularly 0.15 mm to 0.3 mm, which is made by hot kneading a thermoplastic resin composition (particularly preferably vinyl chloride resin/plasticizer, etc.) and melt rolling it by a calendar method or a T-die extrusion method. The resin processing of the woven fabric is performed using a laminator having one or two continuous heat roll/rubber roll compression units, a cooling roll unit, and a winding unit, and the resulting resin-processed woven fabric is hot melt-pressed by a single pass or two passes through the laminator. Tarpaulin is produced by thermocompressing a film obtained by calendar molding onto both sides of an open-mesh fabric using a laminator, and the embodiment of "(thin film layer)/(front) thermoplastic resin layer/fabric (multifilament yarn)/(back) thermoplastic resin layer" having a thickness of 0.5 to 1.5 mm and a mass of 500 to 2000 g/m can be used for membrane structures such as large tents (pavilions), circus tents, tent warehouses, membrane roofs (ceilings) for architectural spaces, and sunshade tents. The embodiment of canvas is a resin-processed fabric produced by impregnating and coating the surface and interior of a fabric with a solution-type thermoplastic resin composition (particularly preferably a paste of vinyl chloride resin/plasticizer, etc.) by a coating method such as knife coating or clearance coating, and then thermally drying or heat-gelling the fabric, or by immersing the fabric in a liquid bath filled with a solution-type thermoplastic resin composition (particularly preferably a vinyl chloride resin paste), and simultaneously pulling it up and squeezing it between a pair of rubber rolls, followed immediately by thermal drying or heat-gelling the fabric by a dipping method. The canvas is manufactured by a dipping method using a paste of polyvinyl chloride resin/plasticizer, etc., and a "(thin film layer)/(front) thermoplastic resin layer/fabric (short fiber spun yarn)/(back) thermoplastic resin layer" configuration with a thickness of 0.3 to 0.8 mm and a mass of 400 to 1000 g/m is suitable for applications such as truck canopies, truck bed sheets, rooftop tents, and sheet houses. In this paragraph, "(thin film layer)/" is an optional additional layer, but is the best configuration for the heat-shielding tent membrane structure of the present invention in terms of extending the service life.

Tent membrane structures include indoor sports, event halls, pavilions, traveling circus tents, tent warehouses, etc., but we will take a tent warehouse as an example. A tent warehouse is made by attaching a waterproof sheet (sewn tarpaulin or waterproof canvas) to the outer periphery of the side walls and the canopy of a frame structure that forms the space, and the roof part is mainly an arch roof kamaboko type or a triangular roof gable type. The size is regulated by the Ministry of Construction as a single-story building with an eave height of 5m or less and a floor area of ^1000m2 or less per building. The construction method of a tent warehouse is generally to assemble the columns of a truss structure that constitutes the main frame material on the ground in advance, to carry out the erection work of each column, to connect each column with horizontal beams and horizontal joints, to hang an arch truss on the column head of the erected column and erect it to complete the frame structure, and finally to cover the exterior with a waterproof sheet (sewn tarpaulin or waterproof canvas). The waterproof sheet is made by connecting and expanding multiple pieces of tarpaulin (or waterproof canvas) cut into long rolls (1-3 m wide, 20-50 m long) according to the part sizes of the tent warehouse. The connection can be achieved by overlapping the ends of the tarpaulin (or waterproof canvas) by 2-10 cm and heat welding the thermoplastic resin layers (the thermoplastic resin layer on the back of the upper tarpaulin and the thermoplastic resin layer on the front of the lower tarpaulin) by a known method such as high-frequency welding, hot air welding, or hot iron welding. The construction arrangement of the waterproof sheet is generally such that the longitudinal direction (wrapping direction) of the tarpaulin (or waterproof canvas) is continuous from the left wall to the canopy to the right wall in relation to the front of the tent warehouse. The inside of the waterproof sheet (the inside of the sewing) is processed so that grommets, hooks, ropes, etc. can be used to fix the waterproof sheet to the frame structure.

The specific examples and performance of the heat-insulating tent membrane structure of the present invention will be further described with reference to the following examples and comparative examples. The weather resistance, heat insulation property, and mold (algae) prevention property of the heat-insulating tent membrane structure were evaluated using the sheet pieces constituting the heat-insulating tent membrane structure, and the performance was applied to the performance of the heat-insulating tent membrane structure.
Accelerated weathering test
In accordance with JIS K5600-7-7 "General coating test methods (Part 7) Long-term durability of coating film," the discoloration of the sheet piece (surface of the thermoplastic resin layer) was evaluated in terms of color difference ΔE (JIS Z8729) after 1000 hours, 1500 hours, and 2000 hours of exposure in a weathering accelerator (based on the sheet piece before acceleration).
ΔE = 0 to 2.9: 1 = No coloring allowed (compliant)
ΔE = 3 to 5.9: 2 = slight coloring is observed (compliant)
ΔE = 6 to 11.9: 3 = Discoloration to light brown (affects appearance)
ΔE=12-19.9: 4=discolored to brown (abnormal appearance)
ΔE=20~: 5=discolored to blackish brown (abnormal appearance)
<Flexural durability after accelerated weathering test>
Using sheet pieces exposed to the weathering accelerator for 1000 hours, 1500 hours, and 2000 hours, a load of 1 kgf was applied to the sheet pieces by bending and kneading 500 times according to JIS L1096, Section 8.19 "Abrasion strength method B (Scott method)", and the abrasion state of the (surface) thermoplastic resin layer and the presence or absence of cracks were evaluated by observing a 100x magnified image of the thermoplastic resin layer using a digital microscope (VHX-1000: Keyence Corporation).
1: No abnormality was found in the thermoplastic resin layer (compliant)
2: Minor cracks are observed in the thermoplastic resin layer, but no peeling or falling off is observed (Compliant)
3: Numerous cracks have occurred in the thermoplastic resin layer, affecting the appearance. 4: Numerous cracks have occurred in the thermoplastic resin layer, with cracked pieces peeling off and falling off. 5: The thermoplastic resin layer has deteriorated and fallen off, exposing the fabric. <Heat shielding rate (%)>
An infrared lamp simulating sunlight was used, and the rate at which the sheet piece blocked radiant heat was taken as the heat blocking rate of the sheet, and was measured according to the following test method.
< Test environment >
An infrared lamp (100V, 125W, iR type: Iwasaki Electric Co., Ltd.) was attached to the center of the ceiling of a box-shaped structure with an inner diameter of 60cm high x 70cm wide x 70cm long, which has outside air temperature insulation and airtightness, and a base (height 8cm) with a heat flow meter (Shothrm HFM heat flow meter: Showa Denko Co., Ltd.) sensor attached was configured in the center of the bottom surface inside the test box. At this time, the distance from the ceiling to the tip of the infrared lamp was 22cm, and the distance from the tip of the infrared lamp to the sensor was 30cm. (22cm + 30cm + 8cm = 60cm) The lamp was turned on in this environment, and the heat flow (kcal/ ^m2h ) was measured every minute, and the heat flow qn (kcal/ ^m2h ) after 30 minutes was measured. After the temperature inside the box-shaped structure was returned to 20°C, a test sheet piece (10 cm long x 10 cm wide) was placed on the base on which the sensor was attached, and a 3.5 mm thick transparent glass plate was placed on top of it. The lamp was then turned on and the heat flow (kcal/ ^m2h ) was measured every minute. The heat flow qc (kcal/ ^m2h ) after 30 minutes was measured, and the heat shielding rate pf (%) was calculated according to equation (2).
Heat shielding rate pf (%) = [(qn - qc) / qn] x 100 ... (1)
The higher the heat shielding rate pf (%), the higher the heat shielding effect.
<Light transmittance (%)>
The measurement was carried out in accordance with JIS Z8722 (condition g) using a spectrophotometer CM-36dGV manufactured by Konica Minolta, Inc.
<Mold resistance>
Accelerated weathering tests according to JIS K5600-7-7 were carried out for 1000 hours, 1500 hours, and 2000 hours, and an agar medium containing a spore mixture of Aspergillus niger FERM S-1 (black mold), (B) Penicillium citrinum FERM S-5 (blue mold), and (C) Cladosporium cladosporioides FERM S-8 (black mold) was dropped onto the surface of the (surface) thermoplastic resin layer of the sheet piece, and the mold growth was observed in a petri dish at 28°C for 7 days, and evaluated according to the following criteria.
1: No mold growth observed
2: Mold partially occurs (occupying less than 20% of the colony area)
3: Mold partially occurs (colony area occupying 21-50%)
4: Mold has appeared in most areas (51-70% of colony area)
5: Mold has appeared over almost the entire surface (colony occupies 71% or more of the surface area)

[Example 1]
<Fabric (1)>
The warp and weft groups were made of 1000 denier (1111 dtex) polyethylene terephthalate (PET) fibers (192 filaments) and S-twisted 50 T/m of PET multifilament yarns, with the warp group having a weave of 16 threads per inch and the weft group having a weave of 16 threads per inch, forming a plain weave fabric. The mass of this fabric (1) was 150 g/ ^m2 , and the void ratio (total of open areas) was 14%.
<Tarpaulin>
This fabric (1) was used as a substrate, and on both sides thereof, a 0.2 mm-thick calendar-molded film made of the soft vinyl chloride resin composition shown in [Formulation 1] below was used as a front and back thermoplastic resin layer, and melt-laminated by thermocompression bonding with a laminator to obtain a tarpaulin (1) having a thickness of 0.7 mm and a mass of 830 g/ ^m2 .
[Formulation 1]: Soft polyvinyl chloride resin composition (compound)
Vinyl chloride resin (degree of polymerization 1300) 100 parts by weight Diisononyl phthalate (plasticizer: Mw 419) 55 parts by weight Tricresyl phosphate (flame retardant plasticizer) 10 parts by weight Epoxidized soybean oil (stabilizer and plasticizer) 5 parts by weight Barium/zinc composite stabilizer 2 parts by weight Antimony trioxide (flame retardant) 10 parts by weight Surface-treated titanium oxide particles (average primary particle size 1 μm) 10 parts by weight * Surface treatment with aluminum oxide (outermost layer stearic acid treatment)
Hindered phenol antioxidant 0.5 parts by weight Benzotriazole tautomer 3 parts by weight *As an enol type, in [Chemical formula 1], the 1st C of one benzene ring (5th tert-butyl group) with 2-hydroxyl group (1 group) / ketone group (0 groups) and the benzotriazole ring (no substituent)
Organic compound of MW267 formed by a C-N bond with a benzotriazole ring (no substituents) and a hydroxyl group (0)/2-ketone group (1) in the keto form (chemical formula 2). The C-N bond (MW267) is formed by a C-N bond with a benzotriazole ring (no substituents) and a hydroxyl group (0)/2-ketone group (1).
*1st, 2nd, and 5th positions indicate the carbon positions of the benzene ring. 10,10'-oxybisphenoxyarsine (mold inhibitor) 0.8 parts by mass

[Example 2]
A tarpaulin (2) having a thickness of 0.7 mm and a mass of 830 g/m2 was obtained in the same manner as in Example 1, except that [Blend 2] was used in which 3 parts by mass of the benzotriazole tautomer in [Blend 1] of Example 1 was replaced with ³ parts by mass of a triazine tautomer.
※Triazine tautomers are enol forms, with the 2-hydroxyl group (1
1) / ketone group (0) benzene ring (4-butoxy group) 3 C at 1 position and 1,3
Organic compound with MW 367 formed by C-C bond with 2,4,6 C of 1,3,5-triazine ring. *As a keto type, in [Chemical formula 4], hydroxyl group (0) / 2-ketone group (1) benzene ring (4-butoxy group) has 1 C at each position and 2,4,6 C of 1,3,5-triazine ring.
C-C bond at position C (MW 367)
* The 1st, 2nd, and 4th positions represent the carbon positions of the benzene ring, and the 2nd, 4th, and 6th positions of the triazine ring
indicates the carbon position, and the 1st, 3rd, and 5th positions indicate the nitrogen N positions.

[Example 3]
A tarpaulin (3) having a thickness of 0.7 mm and a mass of 830 g/m2 was obtained in the same manner as in Example 1, except that [Blend 3] was used in which 3 parts by mass of the benzotriazole tautomer in [Blend 1] of Example 1 was replaced with 3 parts by mass of a ^diphenyl ketone tautomer.
* Diphenyl ketone tautomers are organic compounds with MW 296 in which, as an enol form, in [Chemical formula 5], the 1st C of one benzene ring (no other substituents) with 2-position hydroxyl group (1), ketone group (0), and 4-position octoxy group (1) is bonded to the benzene ring (no other substituents) via a C=O. * As a keto form, in [Chemical formula 6], the 1st C of one benzene ring (no other substituents) with hydroxyl group (0), 2-position ketone group (1), and 4-position octoxy group (1) is bonded to the benzene ring (no other substituents) via a C=O (MW 296).
*1st, 2nd, and 4th positions represent the carbon positions of the benzene ring.

[Example 4]
A tarpaulin (4) having a thickness of 0.7 mm and a mass of 833 g/m2 was obtained in the same manner as in Example 1, except that [Blend 4] was used in which 1 part by mass of titanium oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 μm and 1 part by mass of zinc oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 ^μm was added to [Blend 1] in Example 1.

[Example 5]
A tarpaulin (5) having a thickness of 0.7 mm and a mass of 833 g/m2 was obtained in the same manner as in Example 2, except that [Blend 5] was used in which 1 part by mass of titanium oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 μm and 1 part by mass of zinc oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 μm was added to [Blend ² ] in Example 2.

[Example 6]
Tarpaulin (6) having a thickness of 0.7 mm and a mass of 833 g/m2 was obtained in the same manner as in Example 3, except that [Blend 6] was used in which 1 part by mass of titanium oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 μm and 1 part by mass of zinc oxide particles (surface-treated with aluminum hydroxide/outermost layer-treated with stearic acid) having a primary average particle diameter of 0.2 μm was added to [Blend 3] in Example 3.

[Example 7]
A tarpaulin (7) having a thickness of 0.7 mm and a mass of 835 g/m2 was obtained in the same manner as in Example 1, except that a thin film layer (8 μm) made of a fluorocopolymer resin containing a benzotriazole tautomer and an N-OR hindered amine in a mass ratio of 3:1 was added to ^one surface of the tarpaulin (1) in Example 1. The thin film layer was formed by using a solution of [Blend 7] with a 120 mesh gravure roll coater.
[Formulation 7]: Thin film layer
Fluoroalkyl vinyl ether (containing hydroxyl groups) 100 parts by weight *Paint containing 40% by weight of fluoropolymer resin: Solvent toluene/MEK (1:1)
Hexamethylene diisocyanate (curing agent) 5 parts by weight Benzotriazole tautomer 6 parts by weight *Same keto/enol tautomer as in Example 1 [Chemical formula 1]/[Chemical formula 2]
N-OR type hindered amine 2 parts by mass *Bis(1-undecaoxy-2,2,6,6-tetramethylpiperidin-4-yl)
Carbonate (MW 681)
In the formula 7, R ₁ to R ₄ are all methyl groups, and R ₅ is an undecyl group (-C ₁₁ H ₂₃ ).

[Example 8]
A tarpaulin (8) having a thickness of 0.7 mm and a mass of 835 g/m2 was obtained in the same manner as in Example 2, except that a thin layer (8 μm) of a fluoropolymer resin containing a triazine tautomer and an N-OR hindered amine in a mass ratio of 3:1 was added to one surface of the tarpaulin ( ² ) of Example 2. The thin layer was formed by using a solution of [Blend 8] with a 120 mesh gravure roll coater. [Blend 8] is a composition in which 6 parts by mass of the benzotriazole tautomer in [Blend 7] was replaced with 6 parts by mass of the keto/enol tautomer [Chemical 3]/[Chemical 4], the same as in Example 2.

[Example 9]
A tarpaulin (9) having a thickness of 0.7 mm and a mass of 835 g/m2 was obtained in the same manner as in Example 3, except that a thin layer (8 μm) of a fluoropolymer resin containing a benzophenone tautomer and an N- ^OR type hindered amine in a mass ratio of 3:1 was added to one surface of the tarpaulin (3) of Example 3. The thin layer was formed by using a solution of [Blend 9] with a 120 mesh gravure roll coater. [Blend 9] is a composition in which 6 parts by mass of the benzotriazole tautomer in [Blend 7] is replaced with 6 parts by mass of the keto/enol tautomer [Chemical 5]/[Chemical 6], the same as in Example 3.

[Example 10]
A tarpaulin (10) having a thickness of 0.7 mm and a mass of 835 g/m2 was obtained in the same manner as in Example 1, except that a thin film layer (1 to 3 μm) of a sol-gel condensate containing titanium oxide particles having an average primary particle size of 10 nm (surface treated with aluminum hydroxide/outermost layer treated with stearic acid) and zinc oxide particles having an average primary particle size of 10 nm (surface treated with aluminum hydroxide/ ^outermost layer treated with stearic acid) in a 1:1 mass ratio was added to one surface of the tarpaulin (1) of Example 1. The thin film layer was formed by using a solution of [Blend 10] with a 120 mesh gravure roll coater.
[Formulation 10]: Thin film layer
Ethyl silicate (Si(OC ₂ H ₅ ) ₄ : 40% by mass in terms of SiO ₂ )
* _{Tetraethoxysilane} pentamer of [ _Si5O4 ( _OC2H5 ) ₁₂ ] 100 parts by weight Hydrolysis catalyst: 2% hydrochloric acid 5 parts by weight Titanium oxide (particle diameter 10 nm) 2 parts _by weight Zinc oxide (particle diameter 10 nm) 2 parts by weight Vinyl silane coupling agent (vinyltrimethoxysilane) 5 parts by weight Boric acid ester modified cellulose nanofiber (2% aqueous solution) 100 parts by weight *A modified product in which an aqueous solution of 3% boric acid + 78% ethyl cellosolve reacts with the carboxymethyl groups of carboxymethylated cellulose nanofiber (the primary and secondary hydroxyl groups (2, 3, and 6 positions of cellulose) are carboxymethylated): fiber width 3-10 nm; fiber length 30
~100μm

[Example 11]
A tarpaulin (11) having a thickness of 0.7 mm and a mass of 835 g/ ^m2 was obtained in the same manner as in Example 2, except that a thin film layer of the same sol-gel condensate as in Example 10 was added to one surface of the tarpaulin (2) of Example 2.

[Example 12]
A tarpaulin (12) having a thickness of 0.7 mm and a mass of 835 g/ ^m2 was obtained in the same manner as in Example 3, except that a thin film layer of the same sol-gel condensate as in Example 10 was added to one surface of the tarpaulin (3) of Example 3.

[Example 13]
A tarpaulin (13) having a thickness of 0.7 mm and a mass of 834 g/m2 was obtained in the same manner as in Example 1, except that a thin film layer (1 to 3 μm) of a sol-gel condensate containing photocatalytic titanium oxide (without surface treatment) having an average primary particle size of 10 nm was added to ^one surface of the tarpaulin (1) of Example 1. The thin film layer was formed by using a solution of [Blend 11] with a 120 mesh gravure roll coater.
[Formulation 11]: Thin film layer
Ethyl silicate (Si(OC ₂ H ₅ ) ₄ : 40% by mass in terms of SiO ₂ )
* _{Tetraethoxysilane} pentamer of [ _Si5O4 ( _OC2H5 ) ₁₂ ] 100 parts _by weight Hydrolysis catalyst: 2% hydrochloric acid 5 parts by weight Photocatalytic titanium oxide sol 50 parts by weight *Nitric acid acid: Particle diameter 10 nm: 30% solids in ethanol solution Vinyl silane coupling agent (vinyltrimethoxysilane) 5 parts by weight Silica sol (particle diameter 12 nm: 30% solids in ethanol solution) 50 parts by weight

[Example 14]
A tarpaulin (14) having a thickness of 0.7 mm and a mass of 834 g/ ^m2 was obtained in the same manner as in Example 2, except that a thin film layer of the same sol-gel condensate as in Example 13 was added to one surface of the tarpaulin (2) of Example 2.

[Example 15]
A tarpaulin (15) having a thickness of 0.7 mm and a mass of 834 g/ ^m2 was obtained in the same manner as in Example 3, except that a thin film layer of the same sol-gel condensate as in Example 13 was added to one surface of the tarpaulin (3) of Example 3.

The tarpaulins (1) to (3) of Examples 1 to 3, which have at least a (surface) thermoplastic resin layer containing surface-treated titanium oxide particles (average primary particle size 1 μm), a keto/enol type tautomer, and an antifungal (algae) agent as essential components, are excellent in heat insulation, weather resistance, and antifungal properties, and in particular, the improved weather resistance (reduction of ultraviolet degradation) makes it possible to extend the service life, as revealed by comparison with the sheets obtained in Comparative Examples 1 to 3. In particular, the sheet of Comparative Example 1, which uses surface-treated titanium oxide particles (primary particle size 0.2 μm), has excellent weather resistance but does not provide a sufficient heat insulation effect, while the sheet of Comparative Example 2, which omits the keto/enol type tautomer, has excellent heat insulation effect but does not provide sufficient weather resistance, and the sheet of Comparative Example 3, which omits the antifungal (algae) agent, also has excellent heat insulation effect but does not provide sufficient antifungal properties. Furthermore, the tarpaulins (4) to (6) of Examples 4 to 6, in which surface-treated titanium oxide particles having a primary average particle size of 0.2 μm and surface-treated zinc oxide particles having a primary average particle size of 0.2 μm were added in a 1:1 mass ratio to the thermoplastic resin layer of the heat-shielding tent membrane structures of Examples 1 to 3, showed improved ultraviolet shielding effect (ultraviolet-A and ultraviolet-B waves) in the thermoplastic resin layer, excellent heat shielding properties and weather resistance, and in particular, improved weather resistance (reduction of ultraviolet degradation) enabled further extension of the service life, as revealed by comparison with the sheets of Examples 1 to 3. Furthermore, the tarpaulins (7) to (9) of Examples 7 to 9, in which a thin film layer of a fluorine-based copolymer resin containing a keto/enol tautomer and an N-OR type hindered amine in a mass ratio of 3:1 was added onto the (surface) thermoplastic resin layer of the heat-shielding tent membrane structures of Examples 1 to 3, showed an improved UV shielding effect on the thermoplastic resin layer, excellent heat shielding properties and weather resistance, and in particular, the improved weather resistance (reduction of UV degradation) enabled further extension of the service life, as revealed by comparison with the sheets of Examples 1 to 3. Furthermore, the tarpaulins (10) to (12) of Examples 10 to 12, in which a thin film layer made of a sol-gel condensate containing surface-treated titanium oxide particles having an average primary particle size of 10 nm and surface-treated zinc oxide particles having an average primary particle size of 10 nm in a 1:1 mass ratio was added onto the (surface) thermoplastic resin layer of the heat-shielding tent membrane structures of Examples 1 to 3, showed improved ultraviolet shielding effect (ultraviolet-A and ultraviolet-B waves) for the thermoplastic resin layer, excellent heat shielding properties and weather resistance, and in particular, improved weather resistance (reduction of ultraviolet degradation) enabled further extension of the service life, as revealed by comparison with the sheets of Examples 1 to 3. In addition, the tarpaulins (13) to (15) of Examples 13 to 15, which have a thin film layer made of a sol-gel condensate containing photocatalytic titanium oxide with a primary average particle size of 10 nm added to the (surface) thermoplastic resin layer of the heat-shielding tent membrane structure of Examples 1 to 3, have a self-cleaning effect of the thin film layer, are excellent in heat insulation and weather resistance, and in particular, the improved stain resistance makes it possible to further extend the service life, as compared with the sheets of Examples 1 to 3. As a result of these examples, it was confirmed that by reducing the frequency of disposal (replacing and replacing the membrane structure) and reducing the amount of membrane material (tarpaulin) to be disposed of, and at the same time reducing the production volume of the membrane material (tarpaulin), the consumption of petrochemical resources that cause carbon dioxide emissions will be reduced, and this will contribute to the conservation of the global environment.

[Comparative Example 1]
A tarpaulin (16) having a thickness of 0.7 mm and a mass of 830 g/m2 was obtained in the same manner as in Example 1, except that 10 parts by mass of the surface-treated titanium oxide particles (primary average particle diameter 1 μm) in the thermoplastic resin layer [blending 1] of Example 1 were replaced with 10 parts by mass of surface-treated titanium oxide particles (primary particle diameter ^0.2 μm) [blending 12]. By omitting the use of the surface-treated titanium oxide particles having a primary average particle diameter of 1 μm, which have a high reflectivity in the near-infrared region (780 to 2500 nm), the heat insulation property of the tarpaulin (16) was inferior to that of the tarpaulin (1). However, the weather resistance was equivalent to that of the tarpaulin (1).

[Comparative Example 2]
A tarpaulin (17) having a thickness of 0.7 mm and a mass of 830 g/m2 was obtained in the same manner as in Example 1, except that 3 parts by mass of the benzotriazole-based tautomer was omitted from the thermoplastic resin layer [blending 1] of Example 1, and ¹ part by mass of the N-OR type hindered amine was changed to 3 parts by mass [blending 13] was used. By omitting the use of the tautomer, which is highly effective in converting and releasing ultraviolet energy into molecular vibration energy, the weather resistance of the tarpaulin (17) was inferior to that of the tarpaulin (1), and it was not durable for long-term use. However, the heat shielding property was the same as that of the tarpaulin (1).

[Comparative Example 3]
A tarpaulin (18) having a thickness of 0.7 mm and a mass of 830 g/m2 was obtained in the same manner as in Example 1, except that [blending 14] was used, which was obtained by omitting 0.5 ^parts by mass of the antifungal (algae) agent from the thermoplastic resin layer [blending 1] of Example 1. By omitting the use of the antifungal (algae) agent, the antifungal properties of the tarpaulin (18) were inferior to those of the tarpaulin (1), and it was not durable for long-term use. However, the heat insulation properties were the same as those of the tarpaulin (1).

The present invention makes it possible to obtain a heat-shielding tent membrane structure with improved durability. In other words, it is possible to provide a heat-shielding tent membrane structure that can maintain a clean appearance for a long period of time due to its excellent weather resistance (reduction of ultraviolet degradation) and mold resistance (algae). Specifically, it is ideal for long-term (10 to 15 years) tent structures such as indoor sports facilities, event pavilions, traveling circuses, planetariums, and tent warehouses, and can also be deployed for applications lasting less than 10 years, such as architectural protection (soundproofing) sheets, pergola shades (membrane ceilings), facade sheets, lift-up sheet shutters, partition sheets, truck hoods, outdoor waterproof sheets, and roofed tents. In particular, the extension of the durability of the heat-shielding tent membrane reduces the frequency of disposal (i.e. replacement), and at the same time, the production volume of membrane material is reduced, which reduces the consumption of petrochemical resources that cause carbon dioxide emissions and contributes to the conservation of a sustainable global environment.

Claims (6)

A tent membrane structure with waterproof sheets attached to the outer periphery of the side walls of a frame structure that forms a space, and to the canopy, the waterproof sheets being a connected and sewn product of multiple flexible laminates having a "(surface) thermoplastic resin layer/fabric/(back) thermoplastic resin layer" configuration, and at least the (surface) thermoplastic resin layer essentially comprises surface-treated titanium oxide particles with a primary average particle size of 0.4 to 1.2 μm, keto/enol tautomers, and a fungicide (algae) agent, making this a weather-resistant, heat-insulating tent membrane structure. The heat insulating tent membrane structure according to claim 1, wherein the keto/enol tautomer is at least one selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers. The heat insulating tent membrane structure according to claim 1, wherein the thermoplastic resin layer further contains zinc oxide or a mixture of titanium oxide and zinc oxide, and the zinc oxide and titanium oxide have a primary average particle size of 0.3 μm or less and a coating layer on the particle surface. The heat insulating tent membrane structure according to any one of claims 1 to 3, in which a thin film layer containing one or more keto/enol tautomers selected from benzotriazole tautomers, triazine tautomers, and diphenyl ketone tautomers, and N-OR hindered amines is formed on the (surface) thermoplastic resin layer. A heat insulating tent membrane structure according to any one of claims 1 to 3, in which a thin film layer containing zinc oxide or a mixture of titanium oxide and zinc oxide is formed on the (surface) thermoplastic resin layer, and the zinc oxide and titanium oxide have a primary average particle size of 10 to 50 nm and a coating layer on the particle surface. A heat insulating tent membrane structure as described in any one of claims 1 to 3, in which a thin film layer mainly composed of an organosilicate compound or a sol-gel condensate of a silanol group-containing organic silane compound is formed on the (surface) thermoplastic resin layer, and this thin film layer contains one or more photocatalytic metal oxides selected from titanium oxide, titanium peroxide, zinc oxide, tin oxide, strontium titanate, tungsten oxide, bismuth oxide, and iron oxide.