JP5195366B2 - Coating agent for forming a film having haze value dependency on visible light incident angle - Google Patents

Description

  The present invention relates to a glass substrate, a cover glass used for a display device such as a window glass of a building or a transport aircraft, a mirror, an LCD, an organic EL, or a PDP. That is, it is related with the coating agent for forming the film which provides visual field selectivity.

  Phase separation can be induced in the composition by irradiating the composition having two kinds of ultraviolet light curable resins with ultraviolet light from a certain direction and curing the composition. Patent Documents 1 to 6 disclose articles having dependency on the visible light incident angle of haze using a composition having two kinds of ultraviolet ray curable urethane acrylates having different refractive indexes.

An article having a visible light field incident angle dependency changes the visible light transmittance of the article depending on the direction of observing the article. For example, when it is desired to prevent visual recognition from a specific direction, for example, a partition, a window glass, and a display device This is useful for use when it is desired to prevent visual recognition from a specific direction.
Japanese Unexamined Patent Publication No. 63-309902 Japanese Unexamined Patent Publication No. 64-40903 JP-A 64-40904 Japanese Patent Laid-Open No. 64-40905 Japanese Patent Laid-Open No. 1-1147405 JP-A-2-54201

  The present invention examines a composition type having an ultraviolet ray curable resin having a different refractive index capable of inducing phase separation in the composition by irradiating and curing ultraviolet rays from a certain direction. It is an object of the present invention to provide a coating agent for providing a coating film having improved wear resistance and having a good haze value dependency on a visible light incident angle.

  The coating agent of the present invention is for forming a film having dependency on the visible light incident angle of the haze value, and the coating agent has a high refractive index urethane acrylate and a low refractive index urethane acrylate having ultraviolet light curability, Compound 1 represented by the general formula [1],

Having compound 2 represented by the general formula [2],

The high refractive index urethane acrylate and the low refractive index urethane acrylate each have an acrylic group at both ends of the main chain, and at least one selected from the group of the high refractive index urethane acrylate and the low refractive index urethane acrylate. One is that there are a plurality of acrylic groups on at least one side of the terminal of the main chain, R1 shown in the general formula [1] is an alkyl group having 5 to 12 carbon atoms, and R2 and R3 shown in the general formula [2] are Each is an alkyl group having 1 to 5 carbon atoms, and when the total of all urethane acrylates, compound 1 and compound 2 contained in the coating agent is 100% by mass, there are a plurality of acrylic groups on at least one side of the end of the main chain. 30 to 98.5% by mass of a certain urethane acrylate, 0.25 to 2.5% by mass of Compound 1, and 0.25 to 2.5% by mass of Compound 2 It is characterized in.

  When the base material coated with the coating agent is irradiated with ultraviolet rays, curing occurs while causing phase separation, and a film is formed. In this formation process, urethane acrylates having a similar or identical structure are likely to gather in a form along the ultraviolet irradiation direction, and phases having respective refractive indexes are formed. A typical example of the phase formed by the above method includes a columnar phase as shown in FIGS.

  The urethane acrylate having an acrylic group has a plurality of acrylic groups on at least one side of both ends of the main chain, thereby increasing the crosslink density of the resin forming the film obtained from the coating agent, resulting in the elastic modulus of the film. Will improve.

  And the said compound 1 and 2 are mix | blended with an application | coating agent, and all the urethane acrylates contained in an application | coating agent and the compound 1 and 2 are mix | blended by the above-mentioned ratio, The hardening characteristic by ultraviolet light and abrasion resistance of the film obtained Improve both wear and wear.

  The curing property by ultraviolet light here is a property for causing the obtained coating film to have a haze value dependency on the visible light incident angle, and the coating film shows a good haze value dependency on the visible light incident angle. If it is a thing, it can be said that the said composition had a favorable hardening characteristic.

  By compounding both Compound 1 having a high ultraviolet light absorption ability and Compound 2 which captures radicals and suppresses polymerization of acrylate, and further blends an appropriate amount of acrylate, the composition can be homogenized. Each of the above results in an inseparable relationship, and as a result, the coating obtained by the coating agent of the present invention exhibits a good haze value dependency on the incident angle of visible light and good wear resistance. Presumed to have been.

  In order to increase the crosslink density of the resin forming the coating, it is preferable that the high refractive index urethane acrylate and the low refractive index urethane acrylate have a plurality of urethane acrylates on at least one side of the main chain end, The urethane acrylate is preferably 95 to 98% by mass when the total of all urethane acrylates, Compound 1 and Compound 2 contained in the coating agent is 100% by mass.

  Further, from the viewpoint of increasing the crosslink density of the resin, it is preferable that the number of acrylic groups in all urethane acrylates contained in the coating agent is large, but the homogeneity of the coating agent and unreacted acrylate groups remaining in the coating film In order to reduce the amount, the number of acrylic groups in all urethane acrylates contained in the coating agent is preferably 3 to 20, preferably 3 to 18, and more preferably 3 to 15.

  Furthermore, in order to improve both the dependence of the haze value of the resulting coating on the visible light incident angle and the visible light transmittance of the portion through which visible light is transmitted, a high refractive index urethane acrylate and a low refractive index urethane are used. The difference in refractive index of acrylate is preferably 0.01 to 0.10, and preferably 0.02 to 0.08. The urethane acrylate that forms a phase with a high refractive index is a high refractive index urethane acrylate, the urethane acrylate that forms a phase with a low refractive index is a low refractive index urethane acrylate, and the refractive index difference is the lowest and the highest refractive index value. The difference between the refractive index values.

  The film obtained from the coating agent of the present invention has both good dependency of the haze value on the visible light incident angle and wear resistance. Cover glass used for display devices such as window glass and mirrors for buildings and transportation equipment, LCD, organic EL, PDP, etc., since the coating agent can be applied to the base material to make it an article having visual field selectivity. This is effective when visual field selectivity is required for a glass substrate or the like.

  The coating agent of the present invention comprises a high refractive index urethane acrylate and a low refractive index urethane acrylate having ultraviolet ray curability, a compound 1 represented by the general formula [1],

Having compound 2 represented by the general formula [2],

The high refractive index urethane acrylate and the low refractive index urethane acrylate each have an acrylic group at both ends of the main chain, and at least one selected from the group of the high refractive index urethane acrylate and the low refractive index urethane acrylate. One is a plurality of acrylic groups on at least one side of the end of the main chain.

  Furthermore, a plurality of types of urethane acrylates may be mixed in the high refractive index urethane acrylate and the low refractive index urethane acrylate for the purpose of improving the dependency on the visible light incident angle and the wear resistance. The urethane acrylate to be mixed preferably has an acrylic group in the molecule. When the urethane acrylate having 15 functional groups was mixed with the above low refractive index urethane acrylate, it became clear that the visible light incident angle dependency and the wear resistance were further improved.

  In general, urethane acrylates are prepared from isocyanates, polyols, and acrylates. Examples of the isocyanate include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, phenyl isocyanate, naphthyl isocyanate and the like.

  Examples of the polyol include polyether polyol, polyester polyol, acrylic polyol, polysiloxane polyol and the like. Examples of the polyester polyol include polyethylene glycol, polypropylene glycol, polyol made of a copolymer of ethylene oxide and propylene oxide, and polytetramethylene glycol. Examples of the polyester polyol include caprolactone polyol and polycarbonate polyol.

  As the acrylate, those having a hydroxyl group and one or a plurality of acrylic groups are preferably used. Examples of the hydroxy acrylate having a single acrylic group include hydroxyethyl acrylate, hydroxyacrylic (meth) acrylate, hydroxypropyl acrylate, And hydroxybutyl acrylate. Examples of the hydroxy acrylate having a plurality of acrylic groups (preferably 2 or more and 4 or less) include pentaerythritol triacrylate.

  In order to make the acrylate a urethane acrylate having a plurality of acrylic groups on at least one side of the end of the main chain, it is preferable to use a hydroxy acrylate having a plurality of acrylic groups.

  In order for urethane acrylate to exhibit a high refractive index, it is preferable that the molecule contains at least one structural unit selected from the group of an aromatic ring, a halogen atom excluding fluorine, and a sulfur atom. Moreover, in order for urethane acrylate to show a low refractive index, the molecule may contain fluorine. Since urethane acrylate contains an aromatic ring, a halogen atom and a sulfur atom in the molecule, an acrylate having the above structural unit may be used. Examples of acrylates having the above structural units include phenoxyethyl acrylate, tribromophenyl acrylate, ethylene oxide modified tribromophenyl acrylate, phenylthioacrylate, p-chlorophenylthioacrylate, p- (4-methoxyphenylthio) phenyl acrylate, Naphthalene-2-thioacrylate, bis (4-acryloylthiophenyl) sulfide, bis (acryloylthioethyl) -p-xylyl sulfide, and the like can be given.

  The suitable number average molecular weights of urethane acrylate are 1000-50000, for example, Preferably, it is 1500-30000. When the molecular weight is small, the scattering ability is not sufficiently exhibited, which is not preferable. On the other hand, when the molecular weight is large, the applicability of the coating agent to the substrate may be reduced.

  Moreover, it is preferable that the coating agent of this invention has a photoinitiator. Examples of preferred photopolymerization initiators include benzophenone, 2-hydroxy-2-methylpropionphenone, benzyl, 1-hydroxycyclohexyl phenyl ketone, Michler's ketone, 2-chlorothioxanthone, benzyldimethyl ketal, diethoxyacetophenone, 2,4-diethyl Examples include thioxanthone. The photopolymerization initiator may be added in an amount of 0.001 to 0.05 times, preferably 0.005 to 0.04 times by weight with respect to the total amount of urethane acrylate, compound 1 and compound 2.

  Furthermore, the coating agent of the present invention may have a dilution solvent. As an example of the diluting solvent, those having no active hydrogen group are preferable, and acetones, ethers, and ketones can be used, and examples thereof include methyl ethyl ketone, diacetone alcohol, and isobutyl acetate. In addition, Compound 1 and Compound 2 are commercially available.

  The film having the dependency of the haze value on the incident angle of visible light is obtained by irradiating the precursor film formed on the substrate with the above-mentioned coating agent and irradiating ultraviolet rays with ultraviolet light, It is obtained by a production method having a step of increasing the value.

  For the step of applying, known application methods such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, flexographic printing, brush coating, etc. can be employed.

  In addition, a typical example of the substrate on which the coating agent is applied is glass. Examples of other base materials include a resin film such as polyethylene terephthalate, a resin base material such as polycarbonate, a metal that may be used as a reflective member, and a translucent ceramic.

  It is preferable to use a silane coupling agent that is generally used to improve the adhesion to the substrate, such as 3-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-methacryloxypropyltrimethoxy. Silane or 3-glycidoxypropyltrimethoxysilane is particularly preferable.

  After applying the coating agent to the substrate, for example, a leveling step in which the substrate is allowed to stand in a horizontal place in order to make the surface of the coating flat, or a substrate coated with the coating agent, for example, 50 to 150 ° C. The precursor film may be formed by, for example, providing a heating step.

  The precursor coating is preferably formed on the substrate so as to have a thickness of 50 to 500 μm, preferably 100 to 300 μm. If it is 50 μm or less, it is difficult to develop a good haze value dependency on the visible light incident angle. When the thickness is 500 μm or more, it is difficult to cure while having a good haze value dependency on the incident angle of visible light.

A phase exhibiting a high refractive index is formed along the incident direction of ultraviolet rays. As shown in FIGS. 1 and 2, a phase 7 having a high refractive index is formed by irradiating the precursor film 2 with ultraviolet rays emitted from the ultraviolet light source 1 at a specific angle 3. Thus, a film having the dependency of the haze value on the visible light incident angle is formed. In addition, it is preferable to irradiate the ultraviolet light at this time by using a mercury lamp or the like as a light source and irradiating ultraviolet light having a main wavelength of, for example, 250 nm to 350 nm with an intensity of ² to 30 mW / cm ² .

  As shown in FIG. 3, when the film formed by the above method is irradiated with light from the front, the light goes straight and becomes transmitted light. On the other hand, as shown in FIG. 4, when the film is irradiated with light from a specific angle, the light repeats reflection and scattering at the two-phase interface of 6 and 7 having different refractive indexes, and the light scattering component is Since it increases, the light becomes scattered light. As a result, as shown in FIG. 5, when the object 12 is viewed through the coating 6, an image 10 that is visible to the eye becomes clear when the object is viewed from the front with respect to the coating, whereas When the object is viewed obliquely, the image 11 that is visible to the eye becomes unclear, and thus the coating shows the dependency of the haze value on the visible light incident angle.

  The film thickness of the coating after irradiation with ultraviolet rays is 50 to 500 μm, preferably 100 to 300 μm.

The present invention will be specifically described below with reference to examples. In this example, the refractive index of urethane acrylate, the dependence of the cloudiness of the obtained coating on the incident angle of visible light, and the wear resistance were evaluated by the following measuring methods.
[Refractive index measurement]
Using KPR-200 manufactured by Shimadzu Corporation, the refractive index (wavelength 587 nm) of liquid urethane acrylate at 25 ° C. was measured, and the refractive index difference between high refractive index urethane acrylate and low refractive index urethane acrylate was determined.
[Dependence of haze value on visible light incident angle]
The haze value of the glass substrate on which the film was formed was measured using a haze meter (“NDH2000”, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7105 (1981). In this measurement, the haze value is measured for each incident angle of light incident on the film (measured in the range of 0 to 50 degrees perpendicular to the surface of the film and incident angle 0 to 50 degrees), and visible light ( Irradiation with a wavelength of 380 to 800 nm was performed, and a product having a difference between the maximum fog value and the minimum fog value of 60% or more was determined to be a good product.
[Abrasion resistance]
The abrasion resistance of the glass substrate on which the film was formed was evaluated by a Taber test according to JIS R3212 (1998). Using C180-0-XF as a wear ring and measuring the change in haze when carried out 100 times with a load of 4.9 N, those with ΔH ≦ 30% (preferably ΔH ≦ 10%) did. In addition, the measurement of the haze here was performed from the incident angle direction of the light beam which became the minimum haze value in the evaluation of [dependence of haze value on visible light incident angle].

Example 1
(1) Preparation average polypropylene glycol having a molecular weight of 2000 of the coating agent (New Pole PP-2000, manufactured by Sanyo Chemical) 29.4 g, pentaerythritol triacrylate _{(HOCH 2 -C (CH 2 OCOCH} = CH 2) 3) (PET- 3, Daiichi Kogyo Seiyaku Co., Ltd.) 29.4 g, Tolylene diisocyanate (T-80, Bayer Material Science) 8.2 g, weighed 0.067 g of dibutyltin dilaurate (Kishida Chemical Co.) as a catalyst, A urethane acrylate having a plurality of acrylic groups on at least one side of the molecular ends was prepared. The refractive index of the urethane acrylate was 1.531. This urethane acrylate is designated as urethane acrylate 1.

  Urethane acrylate having 4 acrylic groups and a phenyl group having a refractive index of 1.568 (New Frontier R-1403M (solid content 70%), manufactured by Daiichi Kogyo Seiyaku; this is urethane acrylate) 2) was mixed in an amount of 33 g as a solid content.

Next, in the compound 1 represented by the general formula [1], R1 is iso-C ₈ H ₁₇ (TINUVIN479, manufactured by Ciba Specialty Chemicals), the total of urethane acrylate, compound 1 and compound 2 In the compound 2 represented by the general formula [2], R2 and R3 are both C ₄ H ₉ (TINUVIN 152, Ciba Specialtys) so that 1.03% by mass is 100% by mass (Chemical) was mixed so as to be 2.06% by mass when the total of urethane acrylate, compound 1 and compound 2 was 100% by mass to obtain a coating agent.

  As a photopolymerization initiator before application to the base material, 2-hydroxy-2-methyl-1-phenyl-propan-1-one (DAROCURE 1173, manufactured by Ciba Specialty Chemicals) 0.03 times the amount by weight ratio with respect to the solid content was mixed.

(2) Preparation of substrate on which film is formed 3-Methacryloxypropyltriethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) is moistened with Bencot (M-1, manufactured by Asahi Kasei) on a glass substrate. By contacting the surface of the substrate, 3-methacryloxypropyltriethoxysilane was supplied onto the substrate. Thereafter, the substrate surface was wiped with a wiper made of fiber (trade name “Kim Towel”, manufactured by Nippon Paper Crecia), and 3-methacryloxypropyltriethoxysilane was applied onto the substrate. Next, the coating agent prepared in the above (1) was applied to the base material by setting the film thickness to 250 μm and spreading it with a bar coater (model number K303, manufactured by Print-Coat Instruments).

3. Ultraviolet rays (having main wavelengths of 254 nm, 303 nm, 313 nm, and 365 nm) emitted from an ultraviolet irradiation device (lamp: H03L31, manufactured by Eye Graphics Co., Ltd.) are applied to the coating agent side of the base material coated with the coating agent. Irradiation was performed for 20 minutes in a fixed direction at an intensity of 5 mW / cm ² to obtain a coating film having a visible light incident angle dependency of a haze value of 130 μm.

  The evaluation result of the dependency of the haze value of the obtained coating on the incident angle of visible light was 67%, and the evaluation result of the wear resistance was 4.4%. The results are summarized in Table 1.

Example 2
When R1 in compound 1 represented by the general formula [1] is iso-C ₈ H ₁₇ , when the total of urethane acrylate, compound 1 and compound 2 is 100% by mass, compound 1 is 1. In the compound 2 represented by the general formula [2], R2 and R3 are both C ₄ H ₉ so that the total of the urethane acrylate, the compound 1 and the compound 2 is 100% by mass so as to be 04% by mass. Occasionally, in the same procedure as in Example 1 except that the compound 2 was mixed so as to be 1.04% by mass, a film having a film thickness of 130 μm and a haze value of 130 μm having a visible light incident angle dependency was obtained. . The evaluation result of the dependency of the haze value of the obtained coating on the incident angle of visible light was 62%, and the evaluation result of wear resistance was 4.2%, both of which were good.

Example 3
Except that the amount of tolylene diisocyanate was changed to 19.8 g, using 2-hydroxylethyl acrylate (Acrix HEA, manufactured by Toagosei Co., Ltd.) having one acrylic group instead of pentaerythritol triacrylate when preparing urethane acrylate 1. In the same procedure as in Example 2, a film having a film thickness of 130 μm and a haze value of visible light incident angle dependency was obtained. The evaluation result of the dependency of the haze value of the obtained coating on the incident angle of visible light was 61%, and the evaluation result of the wear resistance was 20%. In this example, urethane acrylate 2 has a refractive index of 1.536, and urethane acrylate 2 is 32.32% by mass when the total of urethane acrylate, compound 1 and compound 2 is 100% by mass. The urethane acrylate 1 has one acrylic group at both ends of the molecule.

Example 4
17.6 g of polypropylene glycol having an average molecular weight of 2000, 17.6 g of pentaerythritol triacrylate, 4.8 g of hexamethylene-1,6-diisocyanate (Desmodur H, manufactured by Sumika Bayer Urethane Co., Ltd.) and 0.04 g of dibutyltin dilaurate as a catalyst are added. Then, 27.0 g of urethane acrylate having 15 functional groups (New Frontier R-1150, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added, and urethane acrylate having a plurality of acrylic groups on at least one side of the molecular end of the main chain. Was prepared. The refractive index of the urethane acrylate was 1.521. This urethane acrylate is designated as urethane acrylate 1.

  The urethane acrylate 1 was mixed with 33 g of New Frontier R-1403M (urethane acrylate 2) having a phenyl group as a solid content.

Next, when R1 in compound 1 represented by the general formula [1] is iso-C ₈ H ₁₇ , when the total of urethane acrylate, compound 1 and compound 2 is 100% by mass, compound 1 In the compound 2 represented by the general formula [2], R2 and R3 are both C ₄ H ₉ so that the total amount of the urethane acrylate, the compound 1 and the compound 2 is 100 mass%. %, The coating film having a cloudiness of 130 μm and having a dependence on the visible light incident angle except that the compound 2 was mixed so as to be 0.98% by mass. Got. The evaluation results of the dependency of the haze value of the obtained coating on the visible light incident angle were 73%, and the evaluation results of the abrasion resistance were 3.6%, both of which were good.

Comparative Example 1
A film having a thickness of 130 μm was obtained in the same procedure as in Example 1 except that compounds 1 and 2 were not used. The evaluation result of the haze value of the obtained coating film on the visible light incident angle is 2%, and the evaluation result of the wear resistance is 6.2%, and the haze value is inferior in the visible light incident angle dependency. It was.

Comparative Example 2
What R1 in the compound 1 represented by the general formula [1] is iso-C ₈ H ₁₇ is 0.52% by mass when the total of the urethane acrylate, the compound 1 and the compound 2 is 100% by mass. As shown, when R2 and R3 in the compound 2 represented by the general formula [2] are both C ₄ H ₉ , the total of urethane acrylate, compound 1 and compound 2 is 100% by mass. A coating was obtained in the same procedure as in Example 1 except that the content was 1% by mass, but the coating was not cured.

Comparative Example 3
What R1 in the compound 1 represented by the general formula [1] is iso-C ₈ H ₁₇ is 3.1% by mass when the total of the urethane acrylate, the compound 1 and the compound 2 is 100% by mass. As shown, when R2 and R3 in the compound 2 represented by the general formula [2] are both C ₄ H ₉ , the total amount of urethane acrylate, compound 1 and compound 2 is 100% by mass. A coating was obtained in the same procedure as in Example 1 except that mixing was performed so that the amount became 52% by mass, but the coating was not cured.

Comparative Example 4
The film thickness was 130 μm in the same procedure as in Example 3 except that urethane acrylate 2 was ethylene oxide-modified tribromophenol acrylate (New Frontier BR-31, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having one acrylic group. A film having the dependency of the haze value on the incident angle of visible light was obtained. The evaluation result of the dependency of the haze value of the obtained film on the incident angle of visible light was 64%, but the evaluation result of the abrasion resistance was inferior to 75%. The urethane acrylate 1 and the urethane acrylate 2 in this comparative example have one acrylic group at each end of the molecule.

Comparative Example 5
A film having a thickness of 130 μm was obtained in the same procedure as in Example 2 except that Compound 1 was not used and Compound 2 was adjusted to 1.05% by mass. The evaluation result of the haze value of the obtained coating film on the visible light incident angle is 35%, and the evaluation result of the wear resistance is 4.5%, and the haze value is inferior in the visible light incident angle dependency. It was.

Comparative Example 6
A film having a film thickness of 130 μm was obtained in the same procedure as in Example 2 except that Compound 2 was not used and Compound 2 prepared by adjusting Compound 1 to 1.05% by mass was not used. The evaluation result of the haze value of the obtained coating on the incident angle of visible light is 2%, and the evaluation result of the wear resistance is 5.5%, which is inferior in the dependency of haze value on the incident angle of visible light. It was.

It is a figure which illustrates typically the formation process of the film which has a visible ray incident angle dependence of the haze seen from the cross-sectional direction of the ultraviolet lamp. It is a figure explaining the phase-separated state of the film which has the visible light incident angle dependence of the haze produced by the method shown in FIG. It is the figure which showed how the light progresses in the film at the time of irradiating light from the front to the film produced by the method shown in FIG. It is the figure which showed how the light progresses in the film at the time of irradiating light from the diagonal to the film produced by the method shown in FIG. It is the figure which showed the image seen through the film produced with the method shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bar-shaped ultraviolet light source 2 Precursor film which has dependence of cloudiness on the incident angle of visible light 3 UV irradiation angle of ultraviolet light irradiated from ultraviolet light source 3 ′ Incident angle of ultraviolet light irradiated from ultraviolet light source to coating film 4 From ultraviolet light source Direction of travel of irradiated ultraviolet ray 5 Reference line 6 Film having refractive index dependence on haze value of visible light (refractive index n1)
The phase of refractive index n2 in the film of 76 (n1 <n2)
8 Traveling direction of light incident on the film 9 Scattered light 10 Image 11 that appears when an object is seen through the film from the front of the film 11 Image 12 that appears when an object is seen through the film as shown in FIG. Object 13 Observer

Claims (5)

It is a coating agent for forming a film having the dependency of the haze value on the incident angle of visible light, and the coating agent is a high refractive index urethane acrylate and a low refractive index urethane acrylate having a UV light curing property, represented by the general formula [1]. Compound 1 represented,

Having compound 2 represented by the general formula [2],

The high refractive index urethane acrylate and the low refractive index urethane acrylate each have an acrylic group at both ends of the main chain, and at least one selected from the group of the high refractive index urethane acrylate and the low refractive index urethane acrylate. One is that there are a plurality of acrylic groups on at least one side of the terminal of the main chain, R1 shown in the general formula [1] is an alkyl group having 5 to 12 carbon atoms, and R2 and R3 shown in the general formula [2] are Each is an alkyl group having 1 to 5 carbon atoms, and when the total of all urethane acrylates, compound 1 and compound 2 contained in the coating agent is 100% by mass, there are a plurality of acrylic groups on at least one side of the end of the main chain. 30 to 98.5% by mass of a certain urethane acrylate, 0.25 to 2.5% by mass of the compound 1 and 0.25 to 2.5% of the compound 2 Coating agent characterized in that it has%. The high refractive index urethane acrylate and the low refractive index urethane acrylate are urethane acrylates having a plurality of acrylic groups on at least one side of the end of the main chain, and the urethane acrylate includes all urethane acrylates contained in the coating agent, the above compound 1 and the above The coating agent according to claim 1, comprising 95 to 98% by mass when the total of the compounds 2 is 100% by mass. The number of acryl groups in all the urethane acrylates contained in a coating agent is 3-20, The coating agent of Claim 1 or Claim 2 characterized by the above-mentioned. The coating agent according to any one of claims 1 to 3, wherein the refractive index difference between the high refractive index urethane acrylate and the low refractive index urethane acrylate is 0.01 to 0.10. A step of applying the coating agent according to any one of claims 1 to 4 to a base material, and irradiating the precursor film formed on the base material with ultraviolet rays, and having a high haze value of the coating film in the irradiation direction. A method for producing a coating film having a dependence of the haze value on the incident angle of visible light.