TWI535789B - Resin film, method for preparing resin film, and coating liquid - Google Patents

Description

Resin film, method for preparing resin film, and coating liquid Field of invention

The present invention relates to a resin film, a method for preparing a resin film, and a coating liquid.

Background of the invention

JP 2009-042351 A discloses an optical film comprising a high refractive layer comprising a cage of sesquiterpene oxide and fine particles of oxidized oxide. Here, although the fine inorganic oxide particles have a core/shell structure, both the core and the shell are composed of an inorganic material. In addition, JP 2009-042351 A discloses an optical film comprising a hard coat layer and a low refractive layer, which also comprises a caged sesquiterpene oxide. According to JP 2009-042351 A, the optical film is expected to exhibit improved strength.

However, the optical film disclosed in JP 2009-042351A has extremely low flexibility and crack resistance. Specifically, despite its high strength, the optical film disclosed in JP 2009-042351A is very soft and is susceptible to cracking even when it is slightly bent. In addition, the optical film hardly recovers when scratched. Therefore, there is a need for an optical film that exhibits high flexibility and restoring force.

Summary of invention

One aspect of the invention pertains to a resin film. The resin film comprises: a matrix comprising sesquioxane as a structural unit; and cerium oxide-containing particles dispersed in the matrix, wherein the cerium oxide-containing particles comprise a cerium oxide-containing core and An organic polymer layer covering the core.

The sesquiterpene oxide may have a cage shape.

The cerium oxide-containing particles may be present in an amount of from 20% by weight (% by weight) to 50% by weight based on the total mass of the substrate and the cerium oxide-containing particles. Within this range, the resin film can exhibit improved flexibility and restoring force while maintaining high strength.

The resin film may have a pencil hardness of 6H or higher.

The organic polymer layer may comprise polyvinylpyrrolidone. Since the shell contains polyvinylpyrrolidone, the resin film has further improved flexibility and restoring force.

The organic polymer layer may have a thickness from 1 nm to 6 nm.

The cerium oxide-containing particles may have an average particle diameter of 50 nm or less.

The resin film includes a first elastic portion derived from the substrate or the core, and a second elastic portion derived from the shell, wherein the first elastic portion and the second elastic portion are interposed in the resin film. The first elastic portion exhibits higher elasticity than the second elastic portion.

Another aspect of the invention relates to a method for preparing a resin film. The method comprises: mixing sesquioxane with oxygen Preparing a coating liquid by using granules of cerium and a solvent having a boiling point of 160 ° C or higher; and preparing a resin film using the coating liquid, wherein the cerium oxide-containing particles comprise a cerium oxide-containing core And an organic polymer layer covering the core. Since a polar solvent having a boiling point of 160 ° C or higher is used as the solvent, the cerium oxide-containing particles can be stably dispersed in the resin film. Therefore, a resin film exhibiting improved bending property and restoring force while maintaining high strength can be prepared.

The sesquiterpene oxide may have a cage shape.

The cerium oxide-containing particles may be present in an amount of from 20% by weight to 50% by weight based on the total weight of the sesquiterpene oxide and the cerium oxide-containing particles.

The solvent can be a polar solvent.

The organic polymer layer may comprise polyvinylpyrrolidone. Since the organic polymer layer of the cerium oxide-containing particles, that is, a shell, comprises polyvinylpyrrolidone, the resin film has further improved flexibility and restoring force.

In one embodiment, preparing the resin film may include: coating the coating liquid on a substrate; forming a coating layer by drying the coating liquid; and irradiating the coating layer with light The caged sesquiterpene oxide in the coating layer is polymerized.

A further aspect of the invention relates to a coating liquid. The coating liquid comprises: a sesquioxane, a cerium oxide-containing particle; and a solvent having a boiling point of 160 ° C or higher; wherein the cerium oxide-containing particles comprise a cerium oxide-containing core and a covering The organic polymer layer of the core. Due to A polar solvent having a boiling point of 160 ° C or higher is used as a solvent for preparing the resin film, and the cerium oxide-containing particles can be stably dispersed in the resin film. Therefore, the resin film exhibiting improved bending property and restoring force while maintaining high strength can be prepared.

The sesquiterpene oxide may have a cage shape.

The cerium oxide-containing particles may be present in an amount of from 20% by weight to 50% by weight based on the total weight of the sesquioxanes and the cerium oxide-containing particles.

The solvent can be a polar solvent.

The coating liquid may further include a polymerization initiator.

10‧‧‧ resin film

20‧‧‧Material

30‧‧‧Parts containing cerium oxide

31‧‧‧nuclear

32‧‧‧ shell

100‧‧‧Substrate

500‧‧‧Tester

500A‧‧‧ Subject

501‧‧‧ pencil

501A‧‧‧Refill

502‧‧‧ level

503‧‧‧Small removable weight

503A‧‧‧ arrow

504‧‧‧clip

505‧‧O-ring

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing a resin film according to an embodiment of the present invention.

Figure 2 is a partial cross-sectional perspective view of a cerium oxide-containing particle in accordance with an embodiment of the present invention.

Figure 3 is a diagram showing the structure of a tester for a pencil rub test.

Fig. 4 is a photograph of a resin film according to Example 1, which was observed after bending the resin film.

Fig. 5 is a photograph observed after bending the resin film according to a resin film of Comparative Example 1.

Fig. 6 is a photograph of a resin film according to Example 1, which was observed immediately after the resin film was rubbed with a pencil.

Fig. 7 is a photograph of the resin film of Fig. 6 observed again after 24 hours.

Detailed description of the preferred embodiment

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification, the same components will be denoted by the same reference numerals, and the repeated description thereof will be omitted for convenience.

1. Composition of resin film

First, a resin film 10 according to an embodiment of the present invention will be described in detail with reference to Figs.

Referring to Fig. 1, the resin film 10 includes a substrate 20 and cerium oxide-containing particles 30. The substrate 20 comprises a sesquioxane, preferably a caged sesquiterpene, as a structural unit. For example, the matrix 20 is formed by polymerization of a caged sesquiterpene oxide. Here, the sesquiterpene oxide (SQ) is a monooxane compound having a skeleton composed of Si-O bonds and represented by the experimental formula (RSiO _1.5 ) _n . The name silsesquioxane is derived from a helium oxide comprising 1.5 (1.5 = sesqui) oxygen atoms in an experimental formula. The sesquiterpene oxide, as understood by the experimental formula (RSiO _1.5 ) _n , is positioned as an intermediate material between the organic cerium oxide SiO ₂ and the organic cerium (R ₂ SiO) _n . In the sesquioxane, the cage sesquiterpene has a cage structure. An example of such a caged sesquiterpene is represented by Chemical Formula 1. It will be appreciated that the caged sesquioxanes according to the present invention are not limited to this formula.

[Chemical Formula 1]

Wherein R is a polymerizable functional group bonded to the R group of another sesquiterpene oxide, and is independently selected from the group consisting of acrylic acid, methacrylic acid, epoxy group, and oxetane. A group of groups.

Preferably, R is an acrylic group. When a specific R is a photopolymerizable functional group (for example, an acrylic group), the caged sesquiterpene is polymerized via R through light irradiation. That is, the cage sesquiterpene oxide is referred to as a photocurable resin. The caged sesquiterpene oxide is converted into a very hard (highly elastic) resin by polymerization. Therefore, the substrate 20 becomes a very hard resin.

The cerium oxide-containing particles 30 are dispersed in the matrix 20 and include a cerium oxide-containing core 31 and an organic polymer layer (ie, shell) 32 covering the core, as shown in FIGS. 1 and 2. . Therefore, the cerium oxide-containing particles 30 have a structure called a core-shell. Preferably, the core 31 is composed of ruthenium oxide. Therefore, the core 31 is very hard (high elasticity).

The shell 32 comprises an organic polymer. In particular, the shell 32 comprises polyvinylpyrrolidone. Preferably, the shell 32 is composed of polyvinylpyrrolidone. Since the shell 32 contains an organic polymer, the shell 32 is more flexible (lower elasticity) than the core 31. When the shell 32 is composed of polyvinylpyrrolidone, the shell 32 exhibits a particularly reduced elasticity. The shell 32 can have The thickness from 1 nm to 6 nm is not limited thereto. Within this range, the resin film exhibits particularly improved flexibility and restoring force. The thickness of the resin film can be measured, for example, by a transmission electron microscope (TEM). In the examples and comparative examples described below, the thickness of the resin film was measured using a transmission electron microscope.

Thus, since the shell 32 of the cerium oxide-containing particles 30 is composed of a flexible organic polymer, the shell 32 exhibits good adhesion to the substrate 20. The resin film 10 includes a highly elastic portion (the substrate 20 and the core 31) and a low elastic portion (the case 32) which are mixed therein. That is, the highly elastic portion and the low elastic portion are spaced apart from each other in the thickness and the planar direction of the resin film 10. In one embodiment, the resin film includes a first elastic portion derived from the substrate or the core, and a second elastic portion derived from the shell, wherein the first portion and the second portion are on the resin film Intermediate phase, and wherein the first elastic portion exhibits higher elasticity than the second elastic portion.

Since the resin film 10 includes the highly elastic portion, the resin film 10 can maintain high strength. This resin film 10 hardly suffers from cracking at the time of bending. That is, the resin film 10 exhibits excellent flexibility. Further, even if the resin film 10 is scratched with a pencil and the like, the resin film 10 can be returned to the original state. That is, the resin film 10 also exhibits an excellent restoring force. The resin film 10 has such excellent flexibility and restoring force that the low elastic portion of the resin film 10 disperses stress caused by bending or scratching, and when the resin film 10 is bent or scratched, Strongly adhered to the surrounding matrix 20.

The cerium oxide-containing particles 30 may have a flatness of 50 nm or less. The average particle diameter, for example, from 1 nm to 40 nm, when the resin film 10 is used as a material of an optical film, is not limited thereto. If the average particle diameter is more than 50 nm, the resin film 10 exhibits a height-increased haze, causing a hazard to transparency.

Here, the average particle diameter of the cerium oxide-containing particles 30 is an arithmetic mean of the particle diameters thereof (when the cerium oxide-containing particles 30 are assumed to be spherical). The particle diameters of the cerium oxide-containing particles 30 are measured using, for example, a laser dispersion/scattering particle size distribution analyzer (specifically, for example, a LA-920 (HORIBA Co., Ltd.)). In addition, the laser dispersion/scattering particle size analyzer is not limited to the LA-920 (HORIBA Co., Ltd.). In the examples and comparative examples described below, the average particle diameter was measured using a LA-920 (HORIBA Co., Ltd.).

Further, the cerium oxide-containing particles 30 are present in an amount of from 20% by weight to 50% by weight based on the total mass of the substrate 20 and the cerium oxide-containing particles 30. Within this range, the cerium oxide-containing particles 30 can provide the aforementioned effects.

This resin film 10 can be used for any purpose without limitation. That is, the resin film 10 can be applied to any technical field requiring high strength and flexibility. For example, the resin film 10 can be applied to an optical film. Specifically, the resin film 10 can be applied to a hard coat layer of an optical film.

2. Method for producing a resin film

Next, a method for producing a resin film will be described in detail. First, a cage of sesquiterpene oxide, cerium oxide-containing particles 30, and a polar solvent having a boiling point of 160 ° C or higher are mixed to prepare a coating. liquid. Here, the cerium oxide-containing particles 30 are present in an amount of from 20% by weight to 50% by weight based on the total weight of the caged sesquiterpene oxide and the cerium oxide-containing particles 30.

In addition, the polar solvent needs to have a boiling point of 160 ° C or higher. When the polar solvent has a boiling point of 160 ° C or higher, the cerium oxide-containing particles 30 may be stably dispersed in the coating liquid, and examples of the polar solvent may include diacetone alcohol (boiling point 166 ° C), propylene glycol ( Boiling point 188 ° C), and the like. Of course, any polar solvent known in the art can be used as long as the polar solvent has a boiling point of 160 ° C or higher.

The polar solvent may be present in the total coating liquid in an amount of from 40% by weight to 80% by weight.

Further, the coating liquid may include an additive known in the art, for example, a polymerization initiator and the like, to which it is added. For example, when the cage sesquiterpene is a photocurable resin, a polymerization initiator can be added to the coating liquid.

Next, a resin film 10 is prepared using the coating liquid. For example, the coating liquid is applied onto a predetermined substrate 100 (see Fig. 3) and dried, thereby forming a coating layer. Next, the caged sesquiterpene oxide in the coating layer is subjected to a polymerization reaction. For example, when the cage sesquiterpene is a curable resin, the coating layer is irradiated with light. For example, the coating layer is irradiated with light using a metal halide lamp. Therefore, the cage sesquiterpene is polymerized, thereby forming a matrix 20. The resin film 10 was prepared by the above procedure.

Hereinafter, the invention will be described in more detail with reference to some examples. It should be understood that these examples are provided for display only, and It is not constructed in any way to limit the invention.

Instance

(Example 1)

In Example 1, a resin film was prepared by the following procedure.

80 parts by weight of propylene glycol was added to 196 parts by weight of a cerium oxide-containing granule solution (Hokko Chemical Industry Co., Ltd., 10.2% by weight of cerium oxide nanoparticles) while stirring, thereby preparing a first mixture. Here, the cerium oxide-containing particle solution used in Example 1 contained 10.2% by weight of cerium oxide-containing particles based on the total weight of the solution. Further, the cerium oxide-containing particles have an average particle diameter of 20 nm. Further, one core is composed of cerium oxide, and one shell is composed of polyvinylpyrrolidone. The shell has a thickness of about 1.5 nm.

Next, 80 parts by weight of one of the caged sesquiterpene oxides (AC-SQ-TA100, TOAGOSEI Co., Ltd.) was added to the first mixture, followed by stirring for 60 minutes, thereby preparing a second mixture. The caged sesquiterpene oxide used in Example 1 has a structure represented by Chemical Formula 1, wherein each R is an acrylic group. Next, 5 parts by weight of one polymerization initiator (Irg 184, BASF JAPAN Co., Ltd.) and 5 parts by weight of RS75 (DIC Co., Ltd.) as an additive were added to the second mixture, followed by stirring. A coating liquid was prepared by this for 30 minutes. The coating liquid contained a solid content of 35 wt% (particles containing cerium oxide + cage sesquiterpene oxide) based on the total weight of the coating liquid. Further, the weight ratio of the cage sesquiterpene oxide to the cerium oxide-containing particles was 80:20.

Then, the coating liquid is applied to a polymerization using a wire bar. The methyl methacrylate (PMMA) substrate (thickness: 1 mm) was allowed to have a thickness of 10 μm. Next, the coating liquid on the substrate was dried at 110 ° C for about 5 minutes, thereby forming a coating layer. Next, the coating layer was irradiated at 2000 mJ, and a metal halide lamp was used, thereby preparing a resin film (hardened film).

(Examples 2 to 5)

The same procedure as in Example 1 was carried out except that the weight ratio of the caged sesquioxane to the cerium oxide-containing particles and the solvent were changed.

(Comparative Examples 1 to 13)

In Comparative Examples 1 and 9 to 13, the same procedure as in Example 1 was carried out except that the weight ratio of the cage sesquiterpene oxide to the cerium oxide-containing particles and the solvent were changed. In Comparative Examples 2 to 8, at least one of the cage sesquiterpene oxide and the particles containing the cerium oxide was replaced with another material, and the weight ratio of the original materials was changed. Table 1 shows the solid content in the solutions prepared in the coating liquids of Examples 1 to 5 and Comparative Examples 1 to 13, in units of wt%, the weight ratio of the original materials, and the solvent. In addition, Table 1 shows the evaluation results, and evaluation methods for the examples and comparative examples will be described below.

In Table 1, "PG" represents propylene glycol and "DAA" represents diacetone alcohol. "MIBK" stands for methyl isobutyl ketone (boiling point: 116.2 ° C). "PGM" stands for propylene glycol methyl ether (boiling point: 120 ° C). The values given to PG and MIBK represent the volume ratio of such solvents. N-BuOH (n-butanol) has a boiling point of 118 ° C and 2-ethoxyethanol has a boiling point of 135 ° C.

In addition, *1 represents a urethane acrylate oligomer U-4HA (Shin-Nakamura Chemical Co., Ltd.). *2 represents cerium oxide microparticles PGM-AC-2140Y (Nissan Chemical Industries, Ltd.). *3 represents finely crosslinked urethane granules Art-Pearl MM (Negami Chemical Industrial Co., Ltd.). *4 represents a core-shell type fine organic particle Silcrusta MK03 (Nikko Rica Co., Ltd.). The core is composed of PMMA and the shell is composed of polyfluorene.

Bending test

In order to evaluate the bendability (scratch resistance) of the resin film, a bending test was performed. Specifically, the resin film formed on the substrate was placed in an oven together with the substrate at 100 ° C for 60 minutes. Then, the Cracks on the resin film were observed with the naked eye. The polymethyl methacrylate formed on the substrate is softened by heating. Therefore, the resin film is bent by the residual curing shrinkage force. When the resin cannot withstand bending, the curved resin film is cracked. The evaluation results are shown in Table 1. The resin film in which the crack cannot be observed by the naked eye is scored as "O", and the crack film can be observed by the naked eye as the resin film is rated as "X".

Pencil friction test

In order to evaluate the strength of the resin film, a pencil rubbing test was carried out in accordance with JIS-K-5600. Here, referring to FIG. 3, one of the testers 500 used in the pencil rubbing test will be described in detail. The conditions of the pencil rubbing test performed using the tester 500 on the resin film 10 according to the present invention are shown in FIG.

The tester 500 includes a main body 500A, a level 502, a small removable weight 503, a clip 504, and an O-ring 505. The main body 500A is formed with a through hole into which a pencil 501 is inserted. An angle θ of 45° is defined between the longitudinal axis direction of the pencil 501 inserted into the through hole and the lower surface of the body 500A (i.e., one surface of the resin film 10). The level 502 is used to secure the assembly of the body 500A level. The small removable weight 503 is used to adjust the load applied to the refill 501A of the pencil 501. The small removable weight 503 is movable in the direction of arrow 503A. The clip 504 allows the pencil 501 to be secured to an inner surface of the body 500A. The O-ring 505 is attached to the body 500A in a surrounding manner. The O-ring 505 is rolled onto the resin film 10, whereby the tester 500 is moved in a test direction.

Next, the method of performing the pencil rubbing test will be described in detail. Here, the method of the pencil rubbing test will be described by taking the pencil rubbing test on the resin film 10 (formed on a substrate 100) according to the present invention as an example.

First, the pencil 501 is inserted and fixed to the tester 500. Next, the refill of the pencil 501 is pressed against the resin film 10. Next, the level of the tester 500 is confirmed using the level 502. Next, the position of the small removable weight 503 is adjusted to apply a load of 750 g to the refill 501A of the pencil 501. Next, the tester 500 was moved in the test direction at a speed of 0.8 mm/sec as shown in FIG. In this way, the refill 501A of the pencil 501 rubs the surface of the resin film 10. Through the above procedure, the pencil rubbing test was carried out. Next, the scratch on the resin film 10 was observed with the naked eye. When the scratch was observed, the hardness of the refill 501A of the pencil 501 was lowered, and then the pencil rubbing test was performed again. When the scratches were not observed, the hardness of the refill 501A of the pencil 501 was increased, and then the pencil rubbing test was performed again. In addition, the maximum hardness (pencil hardness) at which the scratches were not observed by the naked eye was measured on the resin film 10. This hardness is a parameter indicating the strength (scratch resistance) of the resin film 10. The pencil hardness was scored in increasing order, 7H>6H>5H>4H>3H. The evaluation results are shown in Table 1.

Resilience test

The restoring force test was performed using the tester 500 for the pencil rubbing test. Specifically, the pencil rubbing test was carried out as described above, and then the resin film was left alone for 24 hours. Next, the maximum hardness (pencil hardness after 24 hours) at which scratches were not observed (scratches were recovered), It is measured on the resin film. As the resin film exhibits a higher hardness, it is understood that the resin film exhibits higher elasticity. The evaluation results are shown in Table 1.

evaluation result

As shown in Table 1, according to the resin films of Examples 1 to 5, scratches could not be observed. In addition, it can be seen that the resin films according to Examples 1 to 5 exhibited higher strength and restoring force than the resin films according to Comparative Examples 1 to 13. 4 is a photograph of the resin film according to Example 1, which was observed after bending the resin film. Fig. 5 is a view of the resin film according to Comparative Example 1, which was observed after bending the resin film. These photographs were obtained by observing the respective resin films using a laser microscope. Referring to Fig. 4, the resin film according to Example 1 was not cracked even when it was bent. On the other hand, the resin film according to Comparative Example 1 was cracked at the time of bending.

Fig. 6 is a photograph of the resin film according to Example 1, which was observed immediately after the resin film was rubbed with a pencil having a hardness of 7H. Fig. 7 is a photograph of the resin film of Fig. 6 observed again after 24 hours. These photographs were obtained by observing the respective resin films using a laser microscope. Referring to Figures 6 and 7, although the resin film of Example 1 had a scratch 200 when rubbed with the pencil, the scratches 200 disappeared after 24 hours. Therefore, it can be seen that the resin film according to Example 1 exhibited higher strength, and better flexibility and restoring force than the resin film according to Comparative Example 1. From the evaluation results of the resin films according to the examples and the comparative examples, it can be seen that the resin film 10 according to the present invention has high strength, excellent bending property and restoring force.

That is, from the evaluation results of the resin films according to the examples and the comparative examples, it was confirmed that the caged sesquiterpene oxide in the resin film was The proportion of particles containing cerium oxide is in the range of from 80:20 to 50:50, and the resin film provides the desired performance. In addition, it is confirmed that when the caged sesquioxane or the cerium oxide-containing particles are replaced by another raw material, even if the weight ratio of the above materials is within the above range, the resin The membrane did not provide the desired energy. Further, it was also confirmed that the polar solvent used for the preparation of the resin film needs to have a boiling point of 160 ° C or higher.

As such, in accordance with the embodiments of the present invention, the resin film 10 includes the substrate 20, and the substrate 20 includes the cage sesquiterpene oxide as a structural unit and the cerium oxide-containing particles 30. Further, the cerium oxide-containing particles 30 are present in an amount of from 20% by weight to 50% by weight based on the total weight of the substrate 20 and the cerium oxide-containing particles 30. Therefore, the resin film 10 can exhibit improved flexibility and restoring force while maintaining high strength.

Further, according to the embodiments of the present invention, the resin film 10 has further improved flexibility due to the organic polymer layer of the cerium oxide-containing particles 30, that is, the shell 32, including polyvinylpyrrolidone. And recovery.

Further, according to the embodiments of the present invention, since the polar solvent having a boiling point of 160 ° C or higher is used in the preparation of the resin film 10, the cerium oxide-containing particles 30 can be stably dispersed. In the resin film 10. Therefore, it is possible to produce a resin film which exhibits improved bending property and restoring force while maintaining high strength.

Although some embodiments are described in detail with reference to the accompanying drawings, it is to be understood that the embodiments are not constructed The scope of the present invention is limited by the scope of the invention, and various modifications, changes, substitutions, and equivalents may be made without departing from the spirit and scope of the invention.

10‧‧‧ resin film

20‧‧‧Material

30‧‧‧Parts containing cerium oxide

31‧‧‧nuclear

32‧‧‧ shell

Claims (14)

A resin film comprising: a matrix comprising sesquioxane as a structural unit; and cerium oxide-containing particles dispersed in the matrix, wherein the cerium oxide-containing particles comprise a cerium oxide-containing particle And an organic polymer layer covering the core, the organic polymer layer comprising polyvinylpyrrolidone, the weight ratio of sesquiterpene oxide to cerium oxide-containing particles in the resin film is from 80:20 to 50:50 In the scope of. The resin film of claim 1, wherein the sesquiterpene has a cage shape. The resin film of claim 1, wherein the resin film has a pencil hardness of 6H or higher. The resin film of claim 1, wherein the organic polymer layer has a thickness of from 1 nm to 6 nm. The resin film of claim 1, wherein the cerium oxide-containing particles have an average particle diameter of 50 nm or less. The resin film of claim 1, comprising: a first elastic portion derived from the substrate or the core; and a second elastic portion derived from the shell, wherein the first elastic portion and the second elastic portion are The resin film is interphase, and wherein the first elastic portion exhibits a higher bomb than the second elastic portion Sex. A method for preparing a resin film, comprising: preparing a coating liquid by mixing sesquioxanes, particles containing cerium oxide, and a solvent having a boiling point of 160 ° C or higher; And using the coating liquid to prepare a resin film, wherein the cerium oxide-containing particles comprise a cerium oxide-containing core and an organic polymer layer covering the core, the organic polymer layer comprising polyvinylpyrrolidone, the resin film The weight ratio of the sesquiterpene oxide to the cerium oxide-containing particles is in the range of from 80:20 to 50:50. The method of claim 7, wherein the sesquiterpene has a cage shape. The method of claim 7, wherein the solvent is a polar solvent. The method of claim 7, wherein the preparing the resin film comprises: applying the coating liquid onto a substrate; forming a coating layer by drying the coating liquid; and irradiating the coating layer with light The caged sesquiterpene oxide in the coating layer was polymerized. A coating liquid comprising: sesquioxane; cerium oxide-containing particles; and a solvent having a boiling point of 160 ° C or higher, wherein the cerium oxide-containing particles comprise a cerium oxide-containing core and covering One of the core organic polymer layers, The organic polymer layer comprises polyvinylpyrrolidone, and the weight ratio of sesquiterpene oxide to cerium oxide-containing particles in the resin film is in the range of from 80:20 to 50:50. The coating liquid of claim 11, wherein the sesquiterpene has a cage shape. The coating liquid of claim 11, wherein the solvent is a polar solvent. The coating liquid of claim 11, further comprising: a polymerization initiator.