JP2013154481A - Transparent stain resistant sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent stain resistant sheet having high adhesion with organic base materials and fluorine compounds and also having transparency.SOLUTION: A transparent stain resistant sheet is the transparent stain resistant sheet capable of being affixed to a base material, has a transparent base body sheet affixed to the base material, a primer layer affixed to a face in an opposite side of the face affixed to the base material of the transparent base body sheet and having a plurality of convex parts comprising a transparent metal oxide, and a stain resistant layer formed on the primer layer and the base body sheet on which the primer layer is not formed respectively and comprising a silane coupling agent having a perfluoropolyether groups.

Description

  The present invention relates to a transparent antifouling sheet provided with an antifouling layer on the surface, and more particularly to a transparent antifouling sheet in which peeling does not occur between an antifouling layer and a substrate sheet.

  Conventionally, as an antifouling sheet, a wet coating of a fluorine compound on an organic base material such as plastic has been used. However, when the fluorine compound is applied to the surface of the organic substrate, it is difficult to directly apply the fluorine compound on the organic substrate because the adhesion between the organic substrate and the fluorine compound is poor.

  Therefore, an intermediate layer is formed between the organic base material and the fluorine compound to improve the adhesion between the organic base material and the fluorine compound.

  For example, Patent Document 1 describes a method using a silicone polymer or a fluorine polymer as an intermediate layer. However, the method of Patent Document 1 has a problem in that the intermediate layer contains a certain amount of organic components, and thus the adhesion between the intermediate layer and the fluorine compound is insufficient.

  Patent Document 2 describes a method using an acidic aqueous solution in which an inorganic oxide colloidal sol is added to tin (II) ions as an intermediate layer. Here, it is described that when an inorganic material is coated on an organic material, wettability can be improved and a coating film with strong adhesion can be formed.

  However, since these intermediate layers are thin, it is difficult to form them uniformly, and since the intermediate layer contains an inorganic oxide colloidal sol, the transparency of the antifouling sheet is hindered. It was.

JP-A-7-171408 Japanese Patent Application No. 10-256795

  This invention solves the said conventional problem, and it is providing the transparency antifouling sheet which has high adhesiveness of an organic base material and a fluorine compound, and has transparency.

  The transparent antifouling sheet of the present invention is a transparent antifouling sheet that can be affixed to a substrate, the transparent substrate sheet that is affixed to the substrate, and the substrate of the transparent substrate sheet A primer layer that is formed on the surface opposite to the surface to be attached and has a plurality of convex portions made of a transparent metal oxide, and is formed on each of the primer layer and the base sheet, and has a perfluoropolyether group And an antifouling layer comprising a silane coupling agent.

  In one certain form, the porous layer which has two or more granular materials which consist of the same metal oxide as a primer layer between a primer layer and an antifouling layer, and a granular material forms the three-dimensional network structure as a whole. Prepare.

  In one certain form, the primer layer is formed in the ratio of 50%-90% on the base sheet.

  In one certain form, the height of a convex part is 0.005 micrometer-0.4 micrometer, and the distance between the vertexes of an adjacent convex part is 0.005 micrometer-0.4 micrometer, respectively.

  In one certain form, a base sheet consists of a polyethylene terephthalate and a metal oxide is a tin oxide.

  In one certain form, the said primer layer is formed by the ion plating method.

In one certain form, the silane coupling agent which comprises the said antifouling layer consists of either of the compounds represented by the following chemical formula, and the molecular weight is 200-2000.
<Chemical formula 1>
_{R f - (OC 3 H 6} ) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3

<Chemical formula 2>
_{R f - {(OC 3 H} 6) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3} 2
(Rf is a linear or branched perfluoroalkyl group having 1 to 12 carbon atoms, n is an integer of 0 to 4, m is an integer of 0 to 4, l is an integer of 0 to 4, and R is an alkyl group. Is shown.)

  In one certain form, the said silane coupling agent and the said tin oxide are couple | bonded by the covalent bond in the interface of the said primer layer and the said pollution protection layer.

  In one certain form, the silane coupling agent which comprises the said pollution protection layer is not self-condensing.

  In one certain form, the thickness of the said pollution protection layer is 0.002 micrometer-0.02 micrometer.

  The transparent antifouling sheet of the present invention is a transparent antifouling sheet that can be affixed to a substrate, the transparent substrate sheet that is affixed to the substrate, and the substrate of the transparent substrate sheet A primer layer that is formed on the surface opposite to the surface to be attached and has a plurality of convex portions made of a transparent metal oxide, and is formed on each of the primer layer and the base sheet, and has a perfluoropolyether group And an antifouling layer comprising a silane coupling agent. As a result, a transparent antifouling sheet having high adhesion between the organic base material and the fluorine compound and having transparency can be provided.

It is sectional drawing which shows typically the structure of the transparent antifouling sheet | seat of this invention. It is an enlarged view of FIG. It is an enlarged view of FIG. It is sectional drawing which shows typically the structure of the transparent antifouling sheet | seat of this invention.

  Hereinafter, embodiments according to the present invention will be described in more detail with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the parts and portions described in the embodiments of the present invention are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an illustrative example.

1. Transparent antifouling sheet FIG. 1 is a view showing a transparent antifouling sheet 100 of the first embodiment. FIG. 2 is an enlarged view of the α region in FIG. FIG. 3 is an enlarged view of the transparent antifouling sheet 100 of FIG. 1 at the interface between the primer layer 2 and the antifouling layer 3. With reference to FIG. 1, a transparent antifouling sheet 100 of the present invention has a primer layer 2 formed on a base sheet 1 and an antifouling layer 3 formed on the primer layer 2. An adhesive layer 4 is formed on the opposite side of the base sheet 1 where the primer layer 2 is formed.

Base sheet A base sheet is a transparent member for supporting a primer layer and an antifouling layer on a sheet. Moreover, a base sheet is comprised from an organic compound so that it may have a softness | flexibility when sticking to a base material. Examples of the organic compound constituting the base sheet include resin sheets such as polypropylene resin, polyethylene resin, polyamide resin, polyester resin, acrylic resin, and polyvinyl chloride resin. The base sheet may be subjected to surface treatment such as easy adhesion treatment in advance.

  The base sheet is preferably composed of polyethylene terephthalate. When the base sheet is made of polyethylene terephthalate and the convex portion of the primer layer is made of tin oxide, the adhesion between the base sheet and the primer layer is improved. As a result, it can suppress that peeling arises between a base sheet and a primer layer.

Primer layer The primer layer is a layer that improves the adhesion between the base sheet and the antifouling layer. The primer layer is formed between the base sheet and the antifouling layer.

  Referring to FIG. 1 again, the primer layer 2 is composed of a plurality of convex portions 5. A plurality of the convex portions 5 are formed on the base sheet 1 at intervals, and the shape thereof is an island shape. By configuring the primer layer in this way, the antifouling layer 3 is formed on the base sheet on which the convex portions 5 and the convex portions 5 are not formed. As a result, the adhesion between the primer layer 2 and the antifouling layer 3 is improved by the anchor effect.

  The primer layer 2 is preferably formed on the base sheet 1 at a ratio of 50% to 90%. When it is in the above range, the transparency of the primer layer 3 is improved, so that the transparency of the entire transparent antifouling sheet 100 is improved.

  Furthermore, it is preferably 60% to 80%. When in the above range, when the transparent antifouling sheet 100 is adhered to a substrate having a three-dimensional shape, the stress generated in the primer layer 2 can be eliminated in a region where the primer layer 2 is not formed. As a result, the occurrence of cracks in the primer layer 2 can be suppressed.

  With reference to FIG. 2, it is preferable that the height H of the convex part 5 and the distance A between the vertexes of the adjacent convex part 5 are 0.005 μm to 0.4 μm and 0.005 μm to 0.4 μm, respectively. When it is in the above range, the anchor effect is effectively exhibited. As a result, the adhesion between the primer layer 2 and the antifouling layer 3 is further improved.

  Furthermore, it is preferably 0.01 μm to 0.3 μm and 0.01 μm to 0.3 μm, respectively. Within the above range, in addition to improving the adhesion between the primer layer 2 and the antifouling layer 3, it is possible to suppress the generation of rainbows on the surface of the antifouling layer 3.

  In addition, when the height H of the convex part 5 is less than 0.005 μm, there arises a problem that the antifouling property is poor. On the contrary, when the height H exceeds 0.4 μm, the unevenness on the surface is reduced and the adhesion is deteriorated. The problem arises.

  In addition, if the distance A between the vertices is less than 0.005 μm, there is a problem that cracks occur when pasted into a three-dimensional shape. Conversely, if the distance between the vertices exceeds 0.3 μm, the performance of the silane coupling agent is exhibited. The problem of not doing arises.

  The material constituting the convex portion of the primer layer is selected from transparent metal oxides. Examples of the transparent metal oxide include tin oxide, aluminum oxide, magnesium oxide, titanium oxide, zirconium oxide, antimony oxide, indium oxide, bismuth oxide, yttrium oxide, cerium oxide, zinc oxide, and ITO.

  In addition, it is preferable that the convex part of a primer layer is comprised from a tin oxide. When the base sheet is made of polyethylene terephthalate and the convex portion of the primer layer is made of tin oxide, the adhesion between the base sheet and the primer layer is improved. As a result, it can suppress that peeling arises between a base sheet and a primer layer. Furthermore, since tin oxide has particularly excellent transparency among metal oxides, the transparency of the transparent antifouling sheet itself is improved when tin oxide is used for the convex portions.

  The primer layer is formed on the substrate sheet by a vacuum deposition method, a sputtering method, an ion plating method, or the like.

  Among these forming methods, it is preferable to form the primer layer on the base sheet by using an ion plating method. When the primer layer is formed by the ion plating method, the metal oxide particles constituting the primer layer are formed on the substrate sheet in a high energy state. As a result, since the primer layer is formed so as to be embedded in the base sheet, the adhesion between the base sheet and the primer layer is improved.

Antifouling layer The antifouling layer is a layer formed on the surface of the transparent antifouling sheet, and is a layer that exhibits an antifouling function. Note that having an antifouling function means having a water repellency and oil repellency function. In the present text, having water repellency means that the water droplet contact angle is 100 ° or more, and having oil repellency means that the oleic acid contact angle is 60 ° or more.

The antifouling layer is composed of a silane coupling agent having a perfluoropolyether group. Examples of the silane coupling agent having a perfluoropolyether group include compounds represented by the following chemical formula.
<Chemical Formula 3>
_{R f - (OC 3 H 6} ) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3

<Chemical formula 4>
_{R f - {(OC 3 H} 6) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3} 2

  Rf in the formula represents a linear or branched perfluoroalkyl group having 1 to 12 carbon atoms, and R represents an alkyl group. Rf is preferably 8-10.

  R is preferably a methyl group or an ethyl group. When R is a methyl group or an ethyl group, a silanol group is easily generated from an alkoxy group represented by OR. When the silanol group is generated, the metal oxide constituting the primer layer and the silanol group are linked by at least a hydrogen bond. As a result, the adhesion between the primer layer and the antifouling layer is improved.

  n is an integer of 0 to 4, m is an integer of 0 to 4, and l is an integer of 0 to 4. Note that n, m, and l preferably satisfy the relationship of n + m + l ≦ 12. More preferably, n + m + l ≦ 6. It is because the terminal Rf is surface-oriented when it exists in the said range, and the antifouling function which an antifouling layer has improves.

  The molecular weight of the silane coupling agent is preferably 200 to 2000, and more preferably 500 to 1500. This is because the terminal Rf is surface-oriented and the antifouling function of the antifouling layer is improved.

  Referring to FIG. 3, at the interface between antifouling layer 3 and primer layer 2, the silane coupling agent has a metal oxide of convex portion 5 constituting primer layer 2 and a Si-O bond. Preferably it is. When it has a Si—O bond, the adhesion between the antifouling layer 3 and the primer layer 2 is improved.

  In addition, it is more preferable that the silane coupling agent includes three metal oxides and three Si—O bonds in the convex portion 5. If comprised in this way, the adhesiveness of the antifouling layer 3 and the primer layer 2 will further improve. Furthermore, it can prevent that the said silane coupling agent reacts with a time-dependent change and a silicate coupling | bonding produces | generates. As a result, it is possible to prevent the flexibility of the antifouling layer from being lowered.

  Furthermore, the silane coupling agent is preferably not self-condensed. Self-condensation means that silane coupling agents are not provided with a silicate bond. If the silicate bond is not provided, the antifouling layer can be flexible. As a result, when the transparent antifouling sheet is adhered to a substrate having a three-dimensional shape, it is possible to prevent the antifouling layer from being cracked.

  The antifouling layer has a thickness of 0.001 μm to 0.02 μm. More preferably, it is 0.002 μm to 0.01 μm. When the thickness of the antifouling layer is in the range of 0.001 μm to 0.02 μm, the silane coupling agent forms a monomolecular film as shown in FIG. As a result, since the perfluoroalkyl group having water and oil repellency functions is disposed on the surface of the antifouling layer, the water and oil repellency functions of the antifouling layer are dramatically improved.

  When the antifouling layer has a thickness of less than 0.001 μm, the antifouling layer does not have sufficient water and oil repellency functions. On the other hand, when the antifouling layer exceeds 0.02 μm, the silane coupling agent is a single molecule. A film cannot be formed, and the functions of water repellency and oil repellency provided in the antifouling layer are significantly reduced.

The adhesive layer adhesive layer is a layer for adhering the base sheet and the base material, and is formed on the opposite surface of the base sheet on which the primer layer is formed. As a material used for the adhesive layer, a heat-sensitive or pressure-sensitive resin suitable for the type of substrate is used. If the substrate is a PMMA resin, the PMMA resin is also used for the adhesive layer. If the substrate is a PC or polystyrene (PS) resin, these resins have an affinity for PMMA, PS, PA. Resin is used. Furthermore, if the substrate is an inorganic material such as glass, a resin such as a poval resin or a silicon resin is used. Among the above, silicon resin is particularly preferable. This is because the adhesion to the substrate to which the transparent antifouling sheet is attached is improved.

  The adhesive layer is formed on the substrate sheet by a gravure coating method, a roll coating method, a comma coating method, a gravure printing method, a screen printing method, an offset printing method, or the like.

  FIG. 4 is a view showing the transparent antifouling sheet 100 of the second embodiment. With reference to FIG. 4, a transparent antifouling sheet 100 of the present invention has a primer layer 2 formed on a base sheet 1 and an antifouling layer 3 formed on the primer layer 2. A porous layer 6 is formed between the primer layer 2 and the antifouling layer 3. An adhesive layer 4 is formed on the opposite side of the base sheet 1 where the primer layer 2 is formed.

  The basic configuration of the transparent antifouling sheet 100 of the second embodiment is the same as that of the first embodiment, and therefore only the differences will be described here.

Porous layer Referring again to FIG. 4, the porous layer 6 is composed of a plurality of granules 7. The granular material 7 has an average particle diameter of 0.005 μm to 0.05 μm. Moreover, the granular material 7 forms a three-dimensional network structure as a whole. The average particle diameter of the granular material 7 is 0.005 μm to 0.05 μm, and the granular material 7 forms a three-dimensional network structure, so that the antifouling layer 3 enters the porous layer 6 in a complicated manner. As a result, the adhesion between the antifouling layer 3 and the porous layer 6 is very high.

  When the average particle diameter is less than 0.005 μm, the porous layer cannot form a three-dimensional network structure, and the adhesion between the antifouling layer and the porous layer is reduced. On the other hand, if it exceeds 0.05 μm, the surface of the porous layer becomes rough. As a result, when light hits the transparent antifouling sheet, the light is irregularly reflected by the porous layer, and the transparency of the transparent antifouling sheet is inhibited.

  The material of the granular material constituting the porous layer is not particularly limited, but is preferably composed of the same metal oxide as the metal oxide constituting the primer layer. When the material constituting the primer layer and the granular material is the same, the adhesion between the primer layer and the porous layer becomes strong.

  The porous layer is formed on the primer layer by a vacuum deposition method, a sputtering method, an ion plating method, or the like.

  Of these formation methods, the porous layer is preferably formed by the same method as the primer layer. By forming the primer layer and the porous layer by the same method, the primer layer and the porous layer can be formed continuously. As a result, the production cost for producing the transparent antifouling sheet can be suppressed.

<Example 1>
The present invention will be specifically described by the following examples, but the present invention is not limited thereto. In the examples, the amount represented by “part” or “%” is based on weight unless otherwise specified.

Production of Transparent Antifouling Sheet A biaxially stretched polyethylene terephthalate film having a thickness of 50 μm was prepared as a base sheet. This base sheet was set in a vacuum vapor deposition machine, tin was vapor-deposited on the base sheet, and oxygen was sprayed on the deposited tin to form a primer layer made of tin oxide. Thereafter, the same operation was repeated to form a porous layer. When the primer layer and the porous layer formed on the base sheet were measured with an atomic force microscope (manufactured by Shimadzu Corporation, trade name: SPM-9600), the primer layer had a concavo-convex shape. The height was 0.01 μm, and the distance between adjacent convex portions was 0.1 μm. The primer layer was formed on the base sheet at a ratio of 70%. The porous layer had a three-dimensional network structure and the thickness was 0.01 μm. Next, an antifouling layer having a thickness of 0.01 μm is formed on the porous layer using a silane coupling agent (trade name: KY-164, manufactured by Shin-Etsu Chemical Co., Ltd.), and a transparent antifouling sheet Got. The antifouling layer was formed by using a gravure printing method.

<Examples 2-5, Comparative Examples 1-7>
Height of convex and concave portions constituting the primer layer, distance between adjacent convex portions, formation ratio of primer layer, presence or absence of porous layer, thickness of porous layer, type of silane coupling agent, and antifouling layer A transparent antifouling sheet was prepared in the same manner as in Example 1 except that the thickness of was changed.

  Examples and comparative examples were evaluated based on the following evaluation criteria.

(1) Antifouling property
1) The water repellency of the transparent antifouling sheet obtained above was measured and evaluated using a water repellent contact angle meter (trade name: DropMaster, manufactured by Kyowa Interface Science Co., Ltd.). The water repellency evaluation method is as shown below. The results are shown in Table 1.

Evaluation criteria ○: Water droplet contact angle is 110 ° or more and less than 180 ° △: Water droplet contact angle is 100 or more and less than 110 ° ×: Water droplet contact angle is less than 100 °

2) The oil repellency of the transparent antifouling sheet obtained above was measured and evaluated using an oil repellency contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., trade name: DropMaster). In addition, about the evaluation method of oil repellency, it is as showing below. The results are shown in Table 1.

Evaluation criteria ○: oleic acid contact angle of 70 ° or more and less than 180 ° △: oleic acid contact angle of 60 or more and less than 70 ° ×: oleic acid contact angle of less than 60 °

(2) Adhesiveness Based on the cross-cut method described in JIS K5600, the adhesiveness of the transparent antifouling sheet was measured and evaluated. In addition, about the evaluation method of adhesiveness, it is as showing below. The results are shown in Table 1.

Evaluation criteria ○: Classification 0-1
Δ: Classification 2-3
X: Classification 4-5

  The above classifications 0 to 5 indicate the state of the transparent antifouling sheet after cross-cutting. The classification 0 indicates a state in which the cut edge of the transparent antifouling sheet after cross-cutting is completely smooth and there is no peeling to the eyes of any lattice. Category 1 shows that in a transparent antifouling sheet after cross-cutting, a small peeling of the coating film can be observed at the crossing point of the cut, and that the cross-cut part is clearly not exceeding 5%. ing. In category 2, in the transparent antifouling sheet after cross-cutting, the coating film is peeled along the edge of the cut and / or at the intersection, and it is clearly over 5% that the cross-cut part is affected. Shows a state that does not exceed 15%. Classification 3 indicates that in the transparent antifouling sheet after cross-cutting, the coating film is partially or totally peeled along the edge of the cut, and / or various parts of the eyes are partially Or, it is peeled off entirely, and being affected by the cross cut portion clearly indicates a state exceeding 15% but not exceeding 35%. Category 4 is a transparent antifouling sheet after cross-cutting, in which the coating film is partially or completely peeled along the edge of the cut, and / or several eyes are partially or completely. In fact, it shows that the cross-cut portion is clearly not exceeding 35%. Category 5 indicates any degree of peeling that cannot be classified even in category 4 in the transparent antifouling sheet after cross-cutting.

(3) Transparency of the transparent and transparent antifouling sheet is measured by measuring the total light transmittance of the base sheet and the transparent antifouling sheet used when preparing the sheet. This was carried out by introducing it into the following formula and calculating the quasi-total light transmittance. The measurement of the total light transmittance was performed in accordance with the plastic-transparent material test method described in JIS K 7361-Part 1: Single beam method. The evaluation criteria are as shown below. The results are shown in Table 1.
(Formula)
Pseudo total light transmittance = (total light transmittance of substrate sheet / total light transmittance of transparent antifouling sheet) × 100

Evaluation criteria ○: Pseudo total light transmittance is 95% or more and less than 100% △: Pseudo total light transmittance is 80% or more and less than 95% ×: Pseudo total light transmittance is less than 80%

(4) The haze evaluation of the haze transparent antifouling sheet is carried out by measuring the haze value of the base sheet used when preparing the sheet and the transparent antifouling sheet, respectively, and introducing the measured haze value into the following formula: This was done by determining the amount of change in haze value. The haze value was measured in accordance with the method for determining the haze of a plastic-transparent material described in JIS K 7136. The evaluation criteria are as shown below. The results are shown in Table 1.
(Formula)
Change amount of haze value = haze value of transparent antifouling sheet−haze value of substrate sheet

Evaluation criteria ○: Change amount of haze value is less than 0.5 Δ: Change amount of haze value is 1.5 or more, less than 2.0 ×: Change amount of haze value is 2.0 or more

(5) Crackability Evaluation of crackability of a transparent antifouling sheet was carried out by using a tensile tester (Autograph AGS-X: manufactured by Shimadzu Corporation) with an elongation rate of 20 for a sheet of 3 cm × 15 cm. After pulling to become%, the surface was visually observed. The evaluation criteria are as shown below. The results are shown in Table 1.

Evaluation criteria ○: No cracks could be confirmed Δ: 1 to 3 cracks could be confirmed in a 45 cm ² film ×: 3 or more cracks could be confirmed in a 45 cm ² molded product

1 ... Base sheet,
2 ... Primer layer,
3 ... Anti-fouling layer,
4 ... adhesive layer,
5 ... convex part,
6 ... porous layer,
7 ... granular materials,
100: Transparent antifouling sheet,

Claims (10)

A transparent antifouling sheet that can be attached to a substrate,
A transparent substrate sheet adhered to the substrate;
A primer layer comprising a plurality of convex portions made of a transparent metal oxide formed on the surface opposite to the surface to be adhered to the substrate of the transparent substrate sheet;
A transparent antifouling sheet comprising: the primer layer; and an antifouling layer formed on the substrate sheet on which the primer layer is not formed and made of a silane coupling agent having a perfluoropolyether group.   A plurality of granular materials made of the same metal oxide as the primer layer are provided between the primer layer and the antifouling layer, and the granular material includes a porous layer that forms a three-dimensional network structure as a whole. Item 1. The transparent antifouling sheet of item 1.   The transparent antifouling sheet according to claim 1 or 2, wherein the primer layer is formed on the base sheet at a ratio of 50% to 90%.   The transparent antifouling sheet according to claim 1, wherein the height of the convex portions is 0.005 μm to 0.4 μm, and the distance between the apexes of adjacent convex portions is 0.005 μm to 0.4 μm, respectively.   The transparent antifouling sheet according to claim 1, wherein the base sheet is made of polyethylene terephthalate and the metal oxide is made of tin oxide.   The transparent antifouling sheet according to claim 1, wherein the primer layer is formed by an ion plating method. The transparent antifouling sheet according to claim 1, wherein the silane coupling agent is composed of any of the compounds represented by the following chemical formulas, and has a molecular weight of 200 to 2,000.
<Chemical formula 1>
_{R f - (OC 3 H 6} ) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3
<Chemical formula 2>
_{R f - {(OC 3 H} 6) n - (CF 2) m - (CH 2) l -O- (CH 2) -Si (OR) 3} 2
(R _f is a linear or branched perfluoroalkyl group having 1 to 12 carbon atoms, n is
An integer of 0 to 4, m is an integer of 0 to 4, l is an integer of 0 to 4, and R represents an alkyl group. )   The transparent antifouling sheet according to claim 7, wherein the silane coupling agent and the tin oxide are bonded by an Si—O bond at the interface between the primer layer and the antifouling layer.   The transparent antifouling sheet according to claims 6 to 8, wherein the silane coupling agent constituting the antifouling layer is not self-condensed.   The transparent antifouling sheet according to claim 6, wherein the antifouling layer has a thickness of 0.002 μm to 0.02 μm.

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