JP2023150560A - Composite sheet for industrial material excellent in antifouling durability - Google Patents

Abstract

To provide a composite sheet having a base material containing a soft vinyl chloride resin layer which has a transparent resin outermost layer for preventing dirt such as dust and dirt from adhering to the surface, suppresses degradation by ultraviolet rays of the transparent resin outermost layer, and thereby can maintain antifouling property over a long period of time in outdoor use.SOLUTION: A composite sheet has a base material containing at least one soft vinyl chloride resin layer, and a transparent resin outermost layer containing a triazine-based compound, wherein the transparent resin outermost layer satisfies the following expression 1. (Expression 1): 25≤T1×C1≤250, provided that it satisfies 1.0≤T1≤5.0 and 25≤C1≤50. In (Expression 1), T1 represents a thickness (μm) of the transparent resin outermost layer, and C1 represents a content (mass%) of the triazine-based compound in the transparent resin outermost layer.SELECTED DRAWING: Figure 2

Description

The present invention relates to a composite sheet for industrial materials that has excellent stain resistance and durability. More specifically, the present invention provides a composite sheet having a base material layer including a soft vinyl chloride resin layer, which has a transparent resin outermost layer that prevents dirt such as dirt from adhering to the surface, and the transparent By suppressing the deterioration of the outermost resin layer due to ultraviolet rays, it is possible to maintain stain resistance for a long period of time when used outdoors, especially for tent warehouses, event sheets, membrane roofs, sheet shutters, sunshade tents, eaves, blinds, and buildings. A protective material suitable for construction and agricultural materials such as curing sheets, architectural soundproofing sheets, architectural curing mesh, sheets for illuminated signboards, space partition sheets, seat covers, leisure sheets, agricultural houses, livestock sheds, etc. This relates to a composite sheet for industrial materials that has excellent dirt resistance.

A flexible industrial material sheet that includes a fiber base fabric and a soft vinyl chloride resin layer covering the fiber base fabric has a high degree of freedom in design, is easy to assemble and install, and is relatively low cost. Moreover, as a highly durable material, it is used in membrane structures for various fields such as manufacturing, distribution, architecture, agriculture, and livestock farming. However, soft vinyl chloride resin is easily contaminated by dirt and dust, and there is a problem in particular that when the plasticizer contained in the soft vinyl chloride resin layer migrates to the surface, it becomes difficult to remove the adhered dust and dirt. In order to suppress the adhesion of dirt, dust, and other contaminants, a conventional method has been adopted in which the outermost layer of an industrial material sheet is coated with a transparent paint to form an antifouling layer. (For example, see Patent Document 1, paragraph [0023] Example 1) By forming this antifouling layer, the adhesion of dirt such as dirt and dust is initially suppressed, and the transfer of plasticizer from the soft vinyl chloride resin is suppressed to some extent. be able to. In this case, if a resin layer containing, for example, acrylic resin is formed as the antifouling layer, it will have adhesion to the soft vinyl chloride resin layer, and can be sewn at a relatively low cost by high frequency welder fusion or hot air fusion. It is possible to obtain a highly versatile antifouling layer that can be applied to various methods. However, although acrylic resin is a resin with relatively excellent weather resistance, the antifouling layer that is formed is only about 1 μm to several μm thick at most, so it may crack due to deterioration due to ultraviolet rays or cause flapping due to wind. This caused problems such as peeling off, making it difficult to maintain stain resistance for a long period of time.

Also, when industrial material sheets with a soft vinyl chloride resin layer are used for long periods in hot and humid environments such as Japan and Southeast Asia, mold and algae may grow on the sheet surface, which is considered a problem as well as dirt adhesion. has been done. For mold and algae, simply providing an antifouling layer with a paint coating is not very effective, so countermeasures such as adding anti-mold and algae agents to the soft vinyl chloride resin layer are being taken. (For example, see Patent Documents 2 and 3). However, while this method is effective when the anti-mold and algae agents are exposed on the surface, the transfer of these additives to the sheet surface tends to be insufficient, making it difficult to obtain sufficient effects. It wasn't something I could get.

Attempts have also been made to form a protective (resin) layer containing an ultraviolet absorber on the outermost layer of an industrial material sheet (mesh sheet). (For example, see Patent Documents 4 to 6) These are a protective (resin) layer containing an ultraviolet absorber (particularly a hydroxyphenyl triazine compound) on the base material or on the pattern layer (printing layer) provided on the base material. The protective (resin) layer attenuates ultraviolet rays and improves the weather resistance of the base layer and printed layer. However, these technologies do not take into account the improvement of the weather resistance of the protective (resin) layer itself, and are suitable for industrial materials that suppress the migration of plasticizer from the soft vinyl chloride resin layer for a long period of time and have excellent stain resistance and durability. It was not possible to obtain a composite sheet of

Japanese Patent Application Publication No. 2003-073973 Japanese Patent Application Publication No. 09-104088 Japanese Patent Application Publication No. 04-202238 Japanese Patent Application Publication No. 2021-146581 Japanese Patent Application Publication No. 2021-146583 JP 2021-146584 Publication

The present invention provides a composite sheet having a base material including a soft vinyl chloride resin layer, which has an outermost transparent resin layer that prevents dirt such as dust from adhering to the surface, and the outermost layer of the transparent resin is degraded by ultraviolet rays. An object of the present invention is to provide a composite sheet for industrial materials that can maintain stain resistance for a long period of time when used outdoors by suppressing this. The composite sheet of the present invention is suitable for tent warehouses, event sheets, membrane roofs, sheet shutters, sunshade tents, eaves, architectural curing sheets, architectural soundproofing sheets, architectural curing meshes, sheets for illuminated signboards, space partition sheets, and sheets. Suitable for use in outdoor construction and agricultural materials such as covers, leisure sheets, agricultural houses, and livestock sheds.

As a result of intensive studies to solve these problems, we have developed a composite sheet comprising a base material containing at least one soft vinyl chloride resin layer and a transparent resin outermost layer containing a triazine compound, the transparent resin outermost layer comprising: We have discovered that when the outer layer satisfies the following formula 1, it is possible to suppress cracking and peeling of the outermost transparent resin layer of the resulting composite sheet over a long period of time, and to prevent plasticizer migration from the soft vinyl chloride resin layer. The present invention has now been completed.
25 ≦ T ₁ ×C ₁ ≦ 250 (Formula 1)
However, 1.0 ≦ T ₁ ≦ 5.0
The range is 25≦C ₁ ≦50.
*In (Formula 1), _T1 indicates the thickness (μm) of the outermost transparent resin layer,
C1 indicates the content (% by mass) of the triazine compound in the outermost transparent resin layer

In the composite sheet of the present invention, it is preferable that a transparent intermediate layer is further provided between the base material and the transparent resin outermost layer. By providing the transparent intermediate layer, migration of the plasticizer from the soft vinyl chloride resin layer is further suppressed, and higher antifouling properties can be obtained. Furthermore, since the transparent intermediate layer has the outermost layer of a transparent resin containing a triazine-based compound on the transparent intermediate layer, deterioration of the transparent intermediate layer due to ultraviolet rays is suppressed, and antifouling properties can be maintained for a longer period of time.

In the composite sheet of the present invention, the transparent intermediate layer contains at least one compound selected from a benzotriazole compound, a benzophenone compound, and a cyanoacrylate compound, and the transparent intermediate layer satisfies the following formula 2. It is preferable.
25 ≦ T ₂ × C ₂ ≦ 250 (Formula 2)
However, 1.0 ≦ T ₂ ≦ 5.0
The range is 25≦ _C2 ≦50.
*In (Formula 2), _T2 indicates the thickness (μm) of the transparent intermediate layer,
_C2 indicates the content (mass%) of benzotriazole compounds, benzophenone compounds, and cyanoacrylate compounds in the transparent intermediate layer.This further improves the weather resistance of the transparent intermediate layer and also improves the durability of the base material. improves.

According to the present invention, it is possible to provide a composite sheet for industrial materials that has extremely excellent antifouling durability when used outdoors. The composite sheet of the present invention is particularly suitable for tent warehouses, event sheets, membrane roofs, sheet shutters, sunshade tents, eaves, architectural curing sheets, architectural soundproofing sheets, architectural curing meshes, sheets for illuminated signboards, sheets for space partitions, It can be suitably used for outdoor construction and agricultural materials such as seat covers, leisure seats, agricultural houses, and livestock barns, and can maintain a beautiful appearance for a long period of time.

A sectional view showing an example of a composite sheet of the present invention A sectional view showing an example of a composite sheet of the present invention

The composite sheet for industrial materials with excellent antifouling durability of the present invention has a base material including at least one soft vinyl chloride resin layer, and the base material is in the form of a resin sheet (resin film), canvas, It is a waterproof sheet such as tarpaulin. Among these, the resin sheet can be manufactured by a calendar molding method, a T-die extrusion method, a casting method, or the like. Waterproof sheets such as canvas and tarpaulins are laminates that include a soft vinyl chloride resin layer and a base fabric layer made of fiber material, and the soft vinyl chloride resin layer is formed only on one side of the base fabric. It may also be formed on both sides. The canvas is obtained by forming a soft vinyl chloride resin layer by dipping (processing on both sides of the base fabric) using a paste sol, coating process (processing on one side or both sides of the base fabric), and the like. Tarpaulin is produced by laminating a soft vinyl chloride resin film or resin sheet molded by calendar molding, T-die extrusion, or casting with an adhesive layer interposed on one or both sides of a base fabric, or by laminating a coarse fibrous It can be manufactured by a method of thermally laminating both sides of a base fabric made of a knitted fabric through open spaces, and it can also be produced by a combination of dipping or coating and resin film lamination.

The soft vinyl chloride resin layer of the present invention is formed from a composition containing a vinyl chloride resin and a plasticizer. In addition to polyvinyl chloride resin, vinyl chloride resins include chlorinated polyvinyl chloride resin, vinyl chloride-ethylene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinylidene chloride copolymer resin, It includes vinyl chloride-acrylic acid copolymer resin, vinyl chloride-urethane copolymer resin, etc., and these may be used alone or in combination of two or more. There are no particular limitations on the plasticizers used, and examples include phthalate ester plasticizers, fatty acid ester plasticizers, phosphate ester plasticizers, chlorinated paraffin plasticizers, polyester plasticizers, and sulfonate ester plasticizers. agent, citric acid ester plasticizer, trimellitic acid ester plasticizer, acrylic polymer plasticizer, cyclohexanedicarboxylic acid ester plasticizer, cyclohexanedicarboxylic acid ester plasticizer, epoxy plasticizer, ethylene-vinyl acetate-1 Appropriately select one or more plasticizers commonly used for vinyl chloride resins, such as carbon oxide copolymer, ethylene-acrylic acid ester-carbon monoxide copolymer, and difunctional or higher-functional acrylate monomer. It can be used.

The amount of plasticizer contained in the soft vinyl chloride resin layer is preferably 30 to 150 parts by mass, and preferably 40 to 120 parts by mass, as a total amount of plasticizer, based on 100 parts by mass of vinyl chloride resin. is more preferable. If the amount of plasticizer is less than 30 parts by mass, the resulting composite sheet may lack flexibility and may be inferior in handling as a sheet for industrial materials. When the amount of plasticizer exceeds 150 parts by mass, the strength of the soft vinyl chloride resin layer decreases, and when this composite sheet is used to form a membrane structure having heat-sealed sewn portions, the durability of the sewn portions becomes poor. In addition, the plasticizer tends to migrate to the surface of the composite sheet, and the transferred plasticizer may become stained and the appearance may be impaired. Further, from the viewpoint of suppressing migration of the plasticizer to the surface of the composite sheet, it is preferable to use a plasticizer with a molecular weight of 390 or more.

Unless it impedes the purpose of the present invention, the soft vinyl chloride resin layer may also contain organic/inorganic pigments, stabilizers, ultraviolet absorbers, antioxidants, lubricants, processing aids, flame retardants, blowing agents, and surfactants. , water repellent, oil repellent, adhesive, crosslinking agent, curing agent, antistatic agent, conductive filler, filler, antifungal agent, antibacterial agent, algaeproofing agent, insect repellent, deodorant, coupling agent ( Known additives such as silane-based, titanate-based, and aluminate-based additives can be included.

The base material of the present invention preferably has a base fabric layer formed from a fibrous material. Fiber materials used for the base fabric layer include synthetic fibers such as polypropylene fibers, polyethylene fibers, polyester fibers, nylon fibers, and vinylon fibers, natural fibers such as cotton and hemp, semi-synthetic fibers such as acetate, glass fibers, and silica fibers. Inorganic fibers such as , alumina fibers, and carbon fibers may be mentioned, and these may be composed of a single fiber or a mixture of two or more fibers. Among them, polyester fibers can be preferably used because they are highly versatile, have excellent strength and heat resistance. Furthermore, when a nonflammable composite sheet is required, glass fiber is preferably used among inorganic fibers because it is easily available, has excellent strength, and is relatively inexpensive. The base fabric layer in the present invention may be a woven fabric, a knitted fabric, or a non-woven fabric, and in the case of a woven fabric or a knitted fabric, multifilament yarns, short fiber spun yarns, monofilament yarns, or split yarns made of the above-mentioned fibers are used. It may have any structure such as plain weave, twill weave, satin weave, mock-satin weave, or raschel knit weft-inserted tricot using strips or tape yarns. These knitted fabrics are coarse knitted fabrics (porosity is at most 80%, preferably 5 to 50%), each of which is composed of threads including warp and weft arranged in parallel with a gap between the yarns. , and non-coarse knitted fabrics (knitted fabrics in which substantially no gaps are formed between yarns). As the nonwoven fabric, spunbond nonwoven fabric or the like can be used. The base fabric may be subjected to water repellent treatment, water absorption prevention treatment, adhesive treatment, flame retardant treatment, etc., as necessary.

The composite sheet of the present invention has a transparent resin outermost layer containing a triazine compound. The outermost transparent resin layer may be formed only on one side of the base material, or may be formed on both sides. When formed only on one side, the outermost transparent resin layer contains a triazine compound as an essential component. When the outermost transparent resin layer is formed on both sides of the base material, the outermost transparent resin layer on at least one side contains a triazine-based compound as an essential component.

The resin used for the outermost transparent resin layer is not particularly limited as long as it is a resin that can form a transparent film with adhesive properties on the soft vinyl chloride resin layer or the transparent intermediate layer described below, but transparent resins may be used. It is preferable to use a resin that can be sewn by heat sealing between the outermost layers or between the outermost transparent resin layer and the soft vinyl chloride resin layer, such as acrylic resin (homopolymer of acrylic ester or methacrylic ester (or copolymer resins with monomers copolymerizable with these resins), polyurethane resins, polyester resins, polyvinyl acetal resins, and other resins that are soluble in organic solvents, transparent, and thermoplastic. I can do it. For the outermost transparent resin layer, two or more of the above resins may be selected and blended, or the above resins (one or more) and other resins (for example, vinyl acetate resin, PVC/PVC) may be used. Copolymer resins, cellulose ester resins, silicone resins, fluororesins, etc.) can also be blended and used.

The triazine compound used in the outermost layer of the transparent resin in the present invention preferably contains at least one hydroxyphenyltriazine compound selected from monohydroxyphenyltriazine compounds, dihydroxyphenyltriazine compounds, and trishydroxyphenyltriazine compounds. There are no particular limitations on the hydroxyphenyltriazine compound, but examples of monohydroxyphenyltriazine compounds include "2-[4-[(2-hydroxy-3-(dodecyl and tridecyl)oxypropyl)oxy]-2-hydroxyphenyl" -4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine', '2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n- octyloxyphenyl)-1,3,5-triazine”, “2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-iso-octyloxyphenyl)-1,3,5 -triazine', '2-(4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1 , 3,5-triazine', '2-[4,6-di(4-biphenylyl)-1.3.5-triazin-2-yl]-5-(2-ethylhexyloxy)phenol', '2- [4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol”, “6-methylheptane 2-[4-[4,6-di(4-biphenyl)] 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2- (2-ethylhexanoyloxy)ethoxy]phenol”, and dihydroxyphenyltriazine compounds such as “2,4-bis(2-hydroxy-butyroxyphenyl)-6-(2,4-bis-butyroxyphenyl)”. -1,3,5-triazine', '2,4-bis[4-(2-ethylhexyloxy)-2-hydroxyphenyl]-6-(4-methoxyphenyl)-1,3,5-triazine', etc. , as a trishydroxyphenyltriazine compound, for example, "6,6',6''-(1,3,5-triazine-2,4,6-triyl)tris[3-(hexyloxy)-2-methylphenol] ”, “6,6′,6″-(1,3,5-triazine-2,4,6-tolyl)tris(3-butoxyphenol)”, etc. Hydroxyphenyltriazine compounds are excellent as ultraviolet absorbers, and the absorption characteristics of ultraviolet rays differ depending on the structure, so one or more types should be selected and used depending on the absorption wavelength of the resin used for the outermost transparent resin layer. It exhibits high weather resistance. In addition, in many cases, the absorption wavelength band in the ultraviolet region is wide, so the absorption wavelength peaks of the resin and hydroxyphenyltriazine compound do not necessarily have to match, and other factors such as compatibility with the resin used and the outermost layer of the transparent resin An appropriate one may be selected and used, taking into consideration the solubility in the solvent used during formation.

The outermost transparent resin layer of the present invention may also contain a polymeric triazine compound containing a monomer having hydroxyphenyltriazine as a copolymerization component. Here, examples of the monomer having hydroxyphenyltriazine include acrylic, methacrylic, and vinyl unsaturated monomers having hydroxyphenyltriazine in the side chain. Polymer triazine compounds are made by copolymerizing monomers that can be copolymerized with monomers containing hydroxyphenyltriazine (e.g., acrylic acid, methacrylic acid and their derivatives, ethylenically unsaturated compounds such as styrene and vinyl acetate). It is preferable that the monomer to be copolymerized is selected in consideration of compatibility with the resin used for the outermost layer of the transparent resin.

The outermost transparent resin layer of the present invention may contain a triazine compound other than the hydroxyphenyltriazine compound as long as it does not impede the object of the present invention. Examples of such compounds include "2-tert-butylamino-4-cyclopropylamino-6-methylthio-1,3,5-triazine" and "hexahydro-1,3,5-tris(2-hydroxy ethyl)-1,3,5-triazine”, “1,3,5-trimethylhexahydro-1,3,5-triazine”, “2,4-dichloro-6-methoxy-1,3,5-triazine” ”, “2-chloro-4,6-bis(ethylamino)-1,3,5-triazine”, “2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine”, "2,4-bis(ethylamino)-6-methylthio-1,3,5-triazine", "2-ethylamino-4-isopropylamino-6-methylthio-1,3,5-triazine", "2 -Methylthio-4-cyclopropylamino-6-tert-butylamino-1,3,5-triazine", "2-methylthio-4-ethylamino-6-tert-butylamino-1,3,5-triazine" Examples include antibacterial agents, antifungal agents, and antialgal agents such as . When the outermost transparent resin layer contains these, they are more easily exposed to the surface and more effective than when added to the soft vinyl chloride resin layer.

There are no particular limitations on the method of forming the outermost layer of transparent resin, and any method such as coating or laminating may be selected to form the outermost layer. Using a transparent paint prepared by dissolving the A method of coating on a soft vinyl chloride resin layer or a transparent intermediate layer to be described later and drying is preferably used because it is easy to process and advantageous in terms of cost.

In the present invention, the thickness of the outermost transparent resin layer is preferably 1.0 μm to 5.0 μm. If the thickness of the outermost transparent resin layer is less than 1.0 μm, it may not be possible to suppress the adhesion of dirt such as dirt and the migration of plasticizer from the soft vinyl chloride resin layer, and the composite The outermost transparent resin layer may be easily damaged due to friction, flapping, etc. that the sheet receives. Furthermore, even if a triazine compound is contained, deterioration due to ultraviolet rays cannot be sufficiently prevented, and the outermost transparent resin layer may crack or peel off within a short period of time. When the thickness of the outermost transparent resin layer exceeds 5.0 μm, the resin layer becomes brittle and may be easily damaged by friction, flapping, etc. Furthermore, when forming by coating with a resin solution, the drying of the solvent may be insufficient, resulting in problems such as uneven appearance of the manufactured composite sheet and residual solvent odor in the product.

In the transparent resin outermost layer of the present invention, the content of the triazine compound is preferably 25 to 50% by mass, more preferably 30 to 45% by mass. If it is less than 25% by mass, the resistance to irradiation in the ultraviolet absorbing wavelength UV-B region is insufficient, and the outermost layer of the transparent resin may be prone to cracking. If it exceeds 50% by mass, the ultraviolet absorber may precipitate on the surface, impairing the antifouling performance. When a polymeric triazine compound is included as the triazine compound, the content is calculated by setting the mass of the monomer portion containing hydroxyphenyltriazine as the mass of the triazine compound.

In the present invention, it is preferable that the following formula 1 is satisfied, where the thickness of the outermost transparent resin layer is T ₁ (μm) and the content of the triazine compound in the outermost transparent resin layer is C ₁ (% by mass).
25 ≦ T ₁ ×C ₁ ≦ 250 (Formula 1)
However, 1.0 ≦ T ₁ ≦ 5.0
The range is 25≦C ₁ ≦50.
If T ₁ ×C ₁ is less than 25, the outermost transparent resin layer will lack weather resistance and will not be able to sufficiently prevent deterioration due to ultraviolet rays, resulting in the outermost transparent resin layer cracking or peeling off within a short period of time. Sometimes I end up doing something like that. If T ₁ ×C ₁ exceeds 250, the film strength of the outermost transparent resin layer itself may decrease and cracks may easily occur. The reason is that as the proportion of the ultraviolet absorber in the outermost transparent resin layer increases, the proportion of the main resin MMA (acrylic) in the outermost transparent resin layer decreases, resulting in a decrease in film strength. Furthermore, if the outermost transparent resin layer becomes thick, it will not be able to follow the flexibility of the base material, and damage such as cracks will easily occur, resulting in a loss of antifouling performance.

In the present invention, it is preferable to have a transparent intermediate layer between the soft vinyl chloride resin layer and the transparent resin outermost layer. Since the composite sheet of the present invention has a transparent intermediate layer, migration of the plasticizer from the soft vinyl chloride resin layer can be further suppressed. For the transparent intermediate layer, it is preferable to use a resin that has excellent adhesion to both the soft vinyl chloride resin layer and the transparent resin outermost layer. Use one or more selected from among (homopolymer resins of esters or methacrylic acid esters, or copolymer resins with monomers copolymerizable with these), polyurethane resins, polyester resins, polyvinyl acetal resins, etc. Alternatively, other resins (for example, vinyl acetate resin, vinyl chloride/vinyl acetate copolymer resin, cellulose ester resin, silicone resin, fluororesin, etc.) may be blended and used. There are no particular limitations on the method for forming the transparent intermediate layer, but examples include gravure coating, microgravure coating, comma coating, roll coating, reverse roll coating, bar coating, kiss coating, flow coating, etc. It can be formed by coating on the soft vinyl chloride resin layer and drying it by the same method as for the outermost resin layer.

The transparent intermediate layer of the present invention preferably contains one or more compounds selected from benzotriazole compounds, benzophenone compounds, and cyanoacrylate compounds as ultraviolet absorbers. By containing these UV absorbers in the transparent intermediate layer, the soft vinyl chloride resin layer and the transparent intermediate layer are further protected from UV rays, and the migration of the plasticizer can be prevented for a longer period of time to maintain stain resistance. . Examples of benzotriazole compounds include "2-(2'-hydroxy-5'-methylphenyl)benzotriazole" and "2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5 -Chlorobenzotriazole', '2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole', '2-(2'-hydroxy-5'-tert-octylphenyl)benzo triazole', '2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol]', '6-(2-benzotriazolyl)-4-tert-octyl- 6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol, 2-[2-hydroxy-3,5'-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole ”, “2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole”, “2,2'-methylenebis(6-(2-benzotriazol-2-yl) )-4-(1,1,3,3-tetramethylbutyl)phenol)”, “2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole”, “ 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol", "2-(2H-benzo[d][1,2,3]triazol-2-yl) -6-(2-phenylpropan-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol", "2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole ”, “2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole”, “2-(2H-benzotriazol-2-yl)-4,6-di-tert Examples include "-butylphenol" and "2-(2H-benzotriazol-2-yl)-6-sec-butyl-4-tert-butylphenol." Examples of benzophenone compounds include "2-hydroxy-4-methoxybenzophenone", "2-hydroxy-4-n-octyloxybenzophenone", "2,2'-dihydroxy-4,4'-dimethoxybenzophenone", "2, 4-dihydroxybenzophenone'', ``2,2',4,4'-tetrahydroxybenzophenone'', ``2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid'', ``2,2'-dihydroxy-4-methoxy Examples include benzophenone. Examples of cyanoacrylate compounds include "2-ethylhexyl 2-cyano-3,3-diphenylacrylate" and "2,2'-bis{[(2-cyano-3,3'-diphenylacryloyl)oxy]methyl}propane- Examples include ``1,3-diyl bis(2-cyano-3,3'-diphenylacrylate)'' and ``ethyl-2-cyano-3,3'-diphenylacrylate.'' The UV absorber used in the transparent intermediate layer may also include a polymeric UV absorber containing monomers having benzotriazole, benzophenone, and cyanoacrylate as copolymer components. The polymeric ultraviolet absorber is composed of acrylic, methacrylic, and vinyl unsaturated monomers having one selected from benzotriazole, benzophenone, and cyanoacrylate in the side chain, and other monomers ( For example, it can be obtained by copolymerizing acrylic acid, methacrylic acid and their derivatives, and ethylenically unsaturated compounds such as styrene and vinyl acetate. It is preferable that the material be selected in consideration of compatibility with the resin used.

In the present invention, the thickness of the transparent intermediate layer is preferably 1.0 μm to 5.0 μm. If the thickness of the transparent intermediate layer is less than 1.0 μm, it may not be possible to suppress the migration of the plasticizer from the soft vinyl chloride resin layer, and the transparent intermediate layer may be damaged by friction or flapping received by the composite sheet. Peeling may occur between the layer and the soft vinyl chloride resin layer, or between the transparent intermediate layer and the outermost transparent resin layer. Furthermore, even when the transparent intermediate layer contains an ultraviolet absorber, it may not be able to sufficiently protect against ultraviolet rays. When the thickness of the transparent intermediate layer exceeds 5.0 μm, the resin layer becomes brittle and may be easily damaged by friction, flapping, etc. Furthermore, when forming by coating with a resin solution, the drying of the solvent may be insufficient, resulting in problems such as uneven appearance of the manufactured composite sheet and residual solvent odor in the product.

In the transparent intermediate layer of the present invention, the content of the ultraviolet absorber is preferably 25 to 50% by mass, more preferably 30 to 45% by mass. If the ultraviolet absorber is less than 25% by mass, the vinyl chloride resin, which is the main resin of the base material, may be susceptible to cracking when exposed to long wavelength ultraviolet rays in the UV-A region of 320 nm. When cracks occur in the vinyl chloride resin layer, cracks also occur in the outermost transparent resin layer and the transparent intermediate layer, making it easier for the plasticizer to migrate, thereby impairing stain resistance. If it exceeds 50% by mass, the UV absorbers benzotriazole, benzophenone, and cyanoacrylate contained in the transparent resin intermediate layer have lower molecular weights than the triazine compound UV absorbers, and may precipitate on the surface and impair the antifouling performance. . When a polymeric UV absorber is included as the UV absorber, the content is calculated by taking the mass of the monomer portion containing benzotriazole, benzophenone, or cyanoacrylate as the mass of the UV absorber.

In the present invention, it is preferable that the following formula 2 is satisfied, where the thickness of the transparent intermediate layer is T ₂ (μm) and the content of the ultraviolet absorber in the transparent intermediate layer is C ₂ (% by mass).
25 ≦ T ₂ × C ₂ ≦ 250 (Formula 2)
However, 1.0 ≦ T ₂ ≦ 5.0
The range is 25≦ _C2 ≦50.
If T ₂ × C ₂ is less than 25, the weather resistance of the transparent intermediate layer will be insufficient, and deterioration due to ultraviolet rays will not be sufficiently prevented, and the transparent intermediate layer will crack or peel off in a short period of time. As a result, the outermost transparent resin layer formed on the transparent intermediate layer may also crack or peel. When T ₂ ×C ₂ exceeds 250, at least the thickness T ₂ exceeds 5.0 μm or C ₂ exceeds 50% by mass, so the film strength of the transparent intermediate layer itself decreases and cracks are likely to occur. Sometimes. The reason is that as the proportion of the ultraviolet absorber in the transparent intermediate layer increases, the proportion of the main resin MMA (acrylic) in the transparent intermediate layer decreases, resulting in a decrease in film strength. Further, when the transparent intermediate layer becomes thick, it is unable to follow the flexibility of the base material, and damage such as cracks is likely to occur, resulting in a loss of antifouling performance.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Example 1]
<Base material>
(Base fabric 1)
Glass fiber yarn of 1350 dtex (manufactured by Unitika Glass Fiber Co., Ltd.: ECDE75 1/2 3.8S) was used for the warp and weft, and the weave density of the warp was 11.2 threads/cm and the weave density of the weft was 11.8 threads/cm. A plain weave glass fiber fabric (base fabric 1) was obtained by weaving.
<Water absorption prevention treatment>
Next, the base fabric 1 is dipped in an aqueous treatment bath containing 3% fluorine-based water repellent and 2% silane coupling agent, squeezed with a rubber mangle to achieve a pick-up rate of 45%, and dried at 180°C. It was dried in a container for 2 minutes and treated to prevent water absorption.
<Soft vinyl chloride resin layer>
Both the front and back sides of the base fabric 1 which has been subjected to water absorption prevention treatment are coated with vinyl chloride resin paste sol of the following [Formulation 1], and heat treated at 185°C for 2 minutes to give 50 g/m ² (total 100 g/m ^{2 )} on each of the front and back sides. ) a soft PVC coating layer was formed.
[Formulation 1] Vinyl chloride resin paste sol composition
Emulsion polymerized vinyl chloride resin (degree of polymerization 1300) 100.0 parts by mass Di-2-ethylhexyl phthalate (molecular weight 390) (plasticizer) 85.0 parts by mass Antimony trioxide (flame retardant) 50.0 parts by mass Ba-Zn System stabilizer 3.0 parts by mass Benzotriazole compound (ultraviolet absorber) 0.5 parts by mass Isocyanate adhesive 5.0 parts by mass Pigment (titanium oxide) 3.0 parts by mass Next, the following [Formulation 2] The vinyl chloride resin compound composition was heat-melted and kneaded with two rolls at 175°C, passed through an inverted L-shaped calendar roll set at 180°C to form a soft vinyl chloride resin film with a thickness of 0.2 mm, and a soft vinyl chloride resin film was formed on both sides. These soft vinyl chloride resin films were placed in a laminating device so as to be laminated on each of the front and back sides of the base fabric 1 on which the vinyl chloride coating layer was formed, and passed between a pair of rotating rolls in a softened state by heating to 170°C. They were integrated by thermocompression bonding to obtain a base material 1.
[Formulation 2] Vinyl chloride resin compound composition
Suspension polymerized polyvinyl chloride resin (degree of polymerization 1700) 100 parts by mass Diisononyl phthalate (C9: molecular weight 418) (plasticizer) 55 parts by mass Trixylenyl phosphate (molecular weight 410) (flame retardant plasticizer) 15 parts by mass Epoxidation Soybean oil (liquid stabilizer) 5 parts by mass Barium/zinc composite stabilizer 2 parts by mass Benzotriazole compound (ultraviolet absorber) 0.3 parts by mass

Next, the transparent resin outermost layer composition 1 of [Formulation 3] below was coated on one side of the base material 1 using an 80 mesh gravure coater, dried at 100°C for 1 minute, and a transparent resin with a thickness of 2.0 μm was coated. A composite sheet 1 on which the outermost resin layer was formed was obtained.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 1 was 80.
[Formulation 3] Transparent resin outermost layer composition 1 (triazine compound content: 40% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Triazine compound (ultraviolet absorber) 5.4 parts by mass *2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-
[2-(2-ethylhexanoyloxy)ethoxy]phenol Methyl ethyl ketone (dilution solvent) 7.3 parts by mass Toluene (dilution solvent) 7.3 parts by mass

[Example 2]
Composite sheet 2 was obtained using the same procedure and specifications as in Example 1, except that the transparent resin outermost layer composition [Formulation 3] was changed to the following [Formulation 4].
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 2 was 50.
[Formulation 4] Transparent resin outermost layer composition 2 (triazine compound content: 25% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Triazine compound (ultraviolet absorber) 2.7 parts by mass *2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-
[2-(2-ethylhexanoyloxy)ethoxy]phenol Methyl ethyl ketone (dilution solvent) 8.7 parts by mass Toluene (dilution solvent) 8.6 parts by mass

[Example 3]
Composite sheet 3 was obtained using the same procedure and specifications as in Example 1, except that [Blend 3] in Example 1 was changed to [Blend 5] below.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 3 was 100.
[Formulation 5] Transparent resin outermost layer composition 3 (triazine compound content: 50% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Triazine compound (ultraviolet absorber) 8 parts by mass *2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-
[2-(2-ethylhexanoyloxy)ethoxy]phenol Methyl ethyl ketone (dilution solvent) 6 parts by mass Toluene (dilution solvent) 6 parts by mass

[Example 4]
Using a 40 mesh gravure coater, the transparent resin outermost layer composition 1 of [Formulation 3] was coated on one side of the base material 1, and dried at 100°C for 5 minutes to form a transparent resin with a thickness of 5.0 μm. A composite sheet 4 was obtained using the same procedure and specifications as in Example 1 except that the outermost layer was formed.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 4 was 250.

[Example 5]
A composite sheet 5 was obtained using the same procedure and specifications as in Example 1 except that a transparent intermediate layer was provided between the base material 1 and the outermost transparent resin layer. In the composite sheet 5, the transparent intermediate layer is formed by coating the transparent intermediate layer composition 1 of the following [Formulation 6] on one side of the base material 1 with an 80 mesh gravure coater and drying at 100 ° C. for 1 minute, The coating thickness was 2.0 μm.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 5 was 80, and T ₂ ×C ₂ in the transparent intermediate layer was 80.
[Formulation 6] Transparent intermediate layer composition 1 (cyanoacrylate compound content: 40% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Cyanoacrylate compound (ultraviolet absorber) 5.4 parts by mass *2-ethylhexyl 2-cyano-3,3-diphenylacrylate Methyl ethyl ketone (dilution solvent) 7.3 parts by mass Toluene (dilution solvent) 7.3 parts by mass

[Example 6]
Composite sheet 6 was obtained using the same procedure and specifications as in Example 5, except that the composition of the transparent intermediate layer was changed to Transparent Intermediate Layer Composition 2 of [Formulation 7] below.
T ₁ ×C ₁ in the outermost transparent resin layer of the composite sheet 6 was 80, and T ₂ ×C ₂ in the transparent intermediate layer was 80.
[Formulation 7] Transparent intermediate layer composition 2 (benzophenone compound content: 40% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Benzophenone compound (ultraviolet absorber) 5.4 parts by mass *2-ethylhexyl 2-cyano-3,3-diphenylacrylate Methyl ethyl ketone (dilution solvent) 7.3 parts by mass Toluene (dilution solvent) 7.3 parts by mass

[Example 7]
Composite sheet 7 was obtained using the same procedure and specifications as in Example 4, except that the composition of the transparent intermediate layer was changed to Transparent Intermediate Layer Composition 3 of [Formulation 8] below.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 7 was 80, and T ₂ ×C ₂ in the transparent intermediate layer was 80.
[Formulation 8] Transparent intermediate layer composition 3 (benzotriazole compound content: 40% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Benzotriazole compound (ultraviolet absorber) 5.4 parts by mass *2-hydroxy-4-n-octyloxybenzophenone Methyl ethyl ketone (dilution solvent) 7.3 parts by mass Toluene (dilution solvent) 7.3 parts by mass

[Comparative example 1]
Composite sheet 8 of Comparative Example 1 was obtained using the same procedure and specifications as Example 1 except that the outermost transparent resin layer was omitted.

[Comparative example 2]
A composite sheet 9 of Comparative Example 2 was obtained using the same procedure and specifications as in Example 1, except that the outermost transparent resin layer [Formulation 3] was changed to the following [Formulation 9].
[Formulation 9] Transparent resin outermost layer composition 4 (contains no triazine compound)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Methyl ethyl ketone (dilution solvent) 10 parts by mass Toluene (dilution solvent) 10 parts by mass

[Comparative example 3]
Composite sheet 10 of Comparative Example 3 was obtained using the same procedure and specifications as Example 1 except that the transparent resin outermost layer composition was changed to [Formulation 10] below.
T ₁ ×C ₁ in the outermost transparent resin layer of the composite sheet 10 was 20.
[Formulation 10] Transparent outermost layer composition 4 (triazine compound content: 10% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Triazine compound (ultraviolet absorber) 0.9 parts by mass *2-(2'-hydroxy-5'-methylphenyl)benzotriazole Methyl ethyl ketone (dilution solvent) 9.1 parts by mass Toluene (dilution solvent) 10 parts by mass

[Comparative example 4]
Using a 60 mesh gravure coater, the transparent resin outermost layer composition 6 of [Formulation 11] below was coated on one side of the base material 1, and dried at 100°C for 5 minutes to form a transparent resin with a thickness of 4.0 μm. A resin outermost layer was formed to obtain a composite sheet 11.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 10 was 280.
[Formulation 11] Transparent resin outermost layer composition 5 (triazine compound content: 70% by mass)
Acrylic resin (MMA) solution 75 parts by mass *MMA (10% by mass): Methyl ethyl ketone (90% by mass)
Fluorine/acrylic resin 5 parts by mass *Fluorine/acrylic resin (10 mass%): Methyl ethyl ketone (90 mass%)
Triazine compound (ultraviolet absorber) 19 parts by mass *2-hydroxy-4-n-octyloxybenzophenone Methyl ethyl ketone (dilution solvent) 0.5 parts by mass Toluene (dilution solvent) 0.5 parts by mass

[Comparative example 5]
Using a 20 mesh gravure coater instead of an 80 mesh gravure coater, the transparent resin outermost layer composition 3 of [Formulation 5] was coated on one side of the base material 1, and dried at 100 ° C. for 5 minutes. A composite sheet 12 was obtained using the same procedure and specifications as in Example 1, except that a transparent resin outermost layer with a thickness of 6.0 μm was formed.
T ₁ ×C ₁ in the outermost transparent resin layer of composite sheet 12 was 300.

[Comparative example 6]
The transparent resin outermost layer composition 1 of [Formulation 3] was coated on one side of the base material 1 using a 120 mesh gravure coater instead of the 80 mesh gravure coater, and dried at 100°C for 1 minute to obtain a thick A composite sheet 13 was obtained using the same procedure and specifications as in Example 1, except that a transparent resin outermost layer with a thickness of 0.5 μm was formed.
T ₁ ×C ₁ in the outermost transparent resin layer of the composite sheet 13 was 20.

The following tests were conducted on the composite sheets obtained in the above Examples and Comparative Examples, and the results are shown in Tables 1 to 3.
<Accelerated weathering test>
Composite sheets 1 to 13 obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were tested for 624 hours using a xenon weather meter SX75 manufactured by Suga Test Instruments Co., Ltd. with the side on which the outermost transparent resin layer was provided as the irradiation surface. (equivalent to 3 years of outdoor exposure), 1248 hours (equivalent to 6 years of outdoor exposure), 1872 hours (equivalent to 9 years of outdoor exposure), 2496 hours (equivalent to 12 years of outdoor exposure), 3120 hours (equivalent to 15 years of outdoor exposure) Test (JIS K5600-7-7) was conducted.
<Appearance evaluation (cracking, peeling, falling off) after accelerated weathering test>
For composite sheets 1 to 13, a digital microscope (VHX-1000: manufactured by Keyence Corporation) was used to observe the transparent resin outermost layer at a magnification of 500 times at each acceleration time to check for cracks and peeling. The presence or absence of shedding was confirmed, and the evaluation was made as follows. If the evaluation was 1 or 2 for up to 1872 hours of weather resistance promotion, it was considered to be a pass.
1: No cracks, peeling, or falling off of the outermost transparent resin layer.
2: Cracks are observed in the outermost transparent resin layer, but no peeling or falling off is observed.
3: Cracks, peeling, and falling off of the outermost transparent resin layer <Evaluation of antifouling property after weather resistance promotion (dirt chamber test)>
Composite sheets 1 to 13 after weather resistance promotion were subjected to the following antifouling property confirmation test.
A sample composite sheet piece was pasted on the inner wall of a cylindrical airtight container with a diameter of 20 cm and a height of 25 cm, 1 g of carbon toner for copiers and 50 g of dried river sand were added, and a pair of the cylindrical airtight containers were placed horizontally. The cylindrical closed container was contaminated while rotating on rotating rolls (counter-rotating to each other) at a rotation speed of 45 rpm for 30 minutes. Thereafter, the degree of staining was determined as follows (measured without wiping or washing) based on the color difference ΔE (JIS Z8730) before and after the test, and if it was judged as 1 or 2 for up to 1872 hours of weather resistance promotion, it was considered to have passed.
1: ΔE = 0 to 2.9 Good results maintaining the initial state (no problems)
2: ΔE = 3 to 4.9 A little dark, but not bothersome (no problem)
3: ΔE = 5 to 7.9 Dark and worrisome
4: ΔE = 8 to 9.9 Darkness, dirty appearance
5: ΔE=10~ Quite dark and dirty <Bending test>
A bending test was conducted on Composite Sheet 1 (Example 1), Composite Sheet 10 (Comparative Example 4), and Composite Sheet 11 (Comparative Example 5) in accordance with MIT (Bending Test JIS P8115). After bending 1000 times, the bent part was observed using a digital microscope (VHX-1000, manufactured by Keyence Corporation) at a magnification of 500 times, and the presence or absence of cracks in the outermost transparent resin layer and peeling were observed. The presence or absence of shedding was determined.
1: No cracks, peeling, or falling off of the outermost transparent resin layer.
2: Cracks are observed in the outermost transparent resin layer, but no peeling or falling off is observed.
3: Cracks, peeling, and falling off of the outermost transparent resin layer.

Examples (1 to 7) are composite sheets containing a triazine compound, which is an ultraviolet absorber, in the _outermost layer of a transparent resin. C ₁ ) is 25 to 50% by mass and satisfies 25≦T ₁ ×C ₁ ≦250. Therefore, after the xenon weather meter weather resistance accelerated test (K 7350-2: 2008), the outermost transparent resin layer was less likely to peel or crack, and the resistance to ultraviolet rays was improved. In addition, in the antifouling property confirmation test (dirt chamber test) after the accelerated weather resistance test, it was confirmed that deterioration of the antifouling performance over time was suppressed and that the antifouling property could be maintained for a long period of time. In particular, the composite sheets of Examples (5 to 7) having a transparent intermediate layer containing a cyanoacrylate-based, benzophenone-based, or benzotriazole-based ultraviolet absorber had improved resistance to ultraviolet light. The outermost transparent resin layer in Examples 1 to 7 is an antifouling layer containing a triazine compound that is an ultraviolet absorber, and the transparent intermediate layer in Examples 5 to 7 is a cyanoacrylate compound, benzotriazole compound, benzophenone. It is an antifouling layer containing any one of these compounds. The composite sheets of Examples 1 to 7 had improved resistance to ultraviolet rays, and accelerated weather resistance tests (K 7350-2) using a xenon weather meter confirmed that damage such as cracks did not easily occur in the antifouling layer. :2008), we were able to confirm this. In addition, the antifouling property confirmation test (dirt chamber test) confirmed that the antifouling property could be maintained due to the improved resistance to ultraviolet rays of the antifouling layer.

<Evaluation of cracks and peeling of transparent resin outermost layer and transparent intermediate layer after weather resistance promotion>
In Examples 1 to 7, in which the outermost transparent resin layer contained a triazine compound, cracking and peeling of the outermost transparent resin layer were suppressed compared to Comparative Example 2, which did not contain a triazine compound. MMA, which is the main resin of the transparent resin outermost layer and the transparent intermediate layer of Examples (1 to 7), cracks when irradiated with ultraviolet medium wavelength UV-B region 280 nm to 320 nm (acrylic is severely damaged at 315 nm). Such damage may occur. Since triazine-based UV absorbers have a high absorption capacity in the range of 280 nm to 300 nm, we believe that adding them to the outermost layer of the transparent resin improves resistance to irradiation in the UV absorption wavelength UV-B region. It will be done. The greater the amount of the ultraviolet absorber added in Example 3 or the greater the thickness of the outermost transparent resin layer in Example 4, the greater the effect.
Similarly, the products of Examples (5 to 7) in which a transparent intermediate layer was provided between the transparent resin outermost layer and the base material were also effective because the resistance resistance to irradiation in the ultraviolet mid-wavelength UV-B region of 280 nm to 320 nm was improved. is obtained. The transparent intermediate layer contains one of cyanoacrylate-based, benzophenone-based, and benzotriazole-based ultraviolet absorbers. Unlike triazine-based UV absorbers, these UV absorbers have high absorption ability in the long wavelength UV-A region of 320 nm to 380 nm. Vinyl chloride resin, which is the main resin of the base material, deteriorates when exposed to long wavelength ultraviolet rays in the UV-A region of 320 nm. When cracks occur in the soft vinyl chloride resin layer due to deterioration, cracks also occur in the outermost transparent resin layer and the transparent resin intermediate layer, making it easier for the plasticizer to migrate, thereby impairing antifouling performance. Therefore, Examples 5 to 7 in which a transparent resin intermediate layer was provided between the outermost transparent resin layer and the base material had a higher effect of suppressing cracking and peeling. The transparent intermediate layers of Examples 5 to 7 contained any one of cyanoacrylate-based, benzophenone-based, and benzotriazole-based UV absorbers, and the absorption wavelength of each UV absorber was cyanoacrylate-based (280 nm to 360 nm). , benzophenone type (300nm to 390nm), benzotriazole type (340nm to 350nm), and those with high ultraviolet absorption ability in the long wavelength ultraviolet UV-A region 320nm, where vinyl chloride resin is most affected by deterioration, are They are benzophenone type and cyanoacrylate type. Benzotriazole-based products do not have absorption performance in the long wavelength UV-A region of 320 nm. Therefore, as a result, Examples 5 and 6 were slightly better than Example 7.

<Antifouling property confirmation test after weather resistance promotion>
In Examples (1 to 7) and Comparative Examples (1 to 6), antifouling properties were confirmed by conducting an antifouling property confirmation test after an accelerated weather resistance test (K 7350-2: 2008) using a xenon weather meter SX75 manufactured by Suga Test Instruments Co., Ltd. The stain resistance was quantitatively evaluated. As a result, in Comparative Example 4 in which the content of the triazine compound in the outermost layer of the transparent resin exceeded 50% by mass, the antifouling performance was impaired due to precipitation on the surface. On the contrary, Comparative Example 3, in which the content is less than 25% by mass, and Comparative Example 6, in which the coating film of the outermost transparent resin layer is thin, have low resistance to long-wavelength UV-A UV-A and mid-wavelength UV-B irradiation. It was found that cracks were likely to occur in the soft vinyl chloride resin layer of the base material, the outermost transparent resin layer, and the transparent intermediate layer, which made it easier for the plasticizer to migrate from the base material, resulting in a loss of antifouling properties. .

<Bending test (MIT test)>
A bending test was conducted on Composite Sheet 1 (Example 1), Composite Sheet 11 (Comparative Example 4), and Composite Sheet 12 (Comparative Example 5) in accordance with MIT (Bending Test JIS P8115). After bending 1000 times, the bent part was observed using a digital microscope (VHX-1000, manufactured by Keyence Corporation) at a magnification of 500 times, and the presence or absence of cracks in the outermost transparent resin layer and peeling were observed. The presence or absence of shedding was determined. As a result, in composite sheet 12 (Comparative Example 5) in which the coating thickness of the outermost transparent resin layer exceeds 5.0 μm, the outermost transparent resin layer was unable to follow the flexibility of the base material, resulting in damage such as cracking and peeling. This resulted in the following. Composite sheet 11 (Comparative Example 4) also showed cracks in the outermost transparent resin layer. This is probably because C ₂ exceeded 50% by mass and T ₂ ×C ₂ also exceeded 250, so the film strength of the transparent resin outermost layer itself decreased and cracks were likely to occur. The reason is that as the proportion of the ultraviolet absorber in the outermost transparent resin layer increases, the proportion of the main resin MMA (acrylic) in the outermost transparent resin layer decreases, resulting in a decrease in film strength. Furthermore, when the outermost transparent resin layer becomes thicker, it is not possible for the outermost transparent resin layer to follow the flexibility of the base material, and damage such as cracks is likely to occur, resulting in a loss of antifouling performance. Even if the outermost transparent resin layer is made thicker in this manner, if the outermost transparent resin layer is damaged such as cracks or peeling, the plasticizer of the base material will be likely to migrate, resulting in a loss of antifouling performance. On the other hand, Comparative Example 6, in which the coating film thickness was less than 1.0 μm, did not have sufficient resistance to irradiation in the ultraviolet absorption wavelength UV-B region, and cracks were likely to occur in the outermost layer of the transparent resin.

The composite sheet for industrial materials of the present invention has extremely excellent antifouling durability when used outdoors, and can maintain a beautiful appearance for a longer period of time than conventional sheets. Therefore, we manufacture tent warehouses, event sheets, membrane roofs, sheet shutters, sunshade tents, eaves, architectural curing sheets, architectural soundproofing sheets, architectural curing mesh, sheets for illuminated signboards, space partition sheets, seat covers, leisure sheets, It can be suitably used for outdoor construction and agricultural materials such as agricultural houses and livestock sheds.

1: Composite sheet 2: Base material 2-1: Soft vinyl chloride resin layer 2-2: Base fabric 3: Transparent resin outermost layer 4: Transparent intermediate layer

Claims (3)

A composite sheet comprising a base material containing at least one soft vinyl chloride resin layer and a transparent resin outermost layer containing a triazine-based compound, characterized in that the transparent resin outermost layer satisfies the following formula 1, Composite sheet for industrial materials with excellent stain resistance and durability.
25 ≦ T ₁ ×C ₁ ≦ 250 (Formula 1)
However, 1.0 ≦ T ₁ ≦ 5.0
The range is 25≦C ₁ ≦50.
*In (Formula 1), _T1 indicates the thickness (μm) of the outermost transparent resin layer,
_C1 indicates the content (% by mass) of triazine compounds in the outermost transparent resin layer The composite sheet according to claim 1, further comprising a transparent intermediate layer between the base material and the outermost transparent resin layer. The transparent intermediate layer contains at least one compound selected from a benzotriazole compound, a benzophenone compound, and a cyanoacrylate compound, and the transparent intermediate layer satisfies the following formula 2. Composite sheet according to item 2.
25 ≦ T ₂ × C ₂ ≦ 250 (Formula 2)
However, 1.0 ≦ T ₂ ≦ 5.0
The range is 25≦ _C2 ≦50.
*In (Formula 2), _T2 indicates the thickness (μm) of the transparent intermediate layer,
_C2 indicates the content (% by mass) of benzotriazole compounds, benzophenone compounds, and cyanoacrylate compounds in the transparent intermediate layer.