JP7496271B2 - Anti-fogging laminate and method for producing same - Google Patents

Description

This disclosure relates to an anti-fogging laminate and a method for producing the same.

2. Description of the Related Art In recent years, there are cases where a substrate made of an organic material such as plastic or an inorganic material such as glass is required to have a property of being less likely to fog up (anti-fogging property).
For example, Patent Document 1 discloses a method for producing a laminate having anti-fogging properties (i.e., an anti-fogging laminate), which comprises applying a curable composition containing a (meth)acrylic monomer to a substrate to form a coating layer, and curing the formed coating layer to convert it into a cured layer, thereby producing an anti-fogging laminate including a substrate and a cured layer.

International Publication No. 2019/221268

However, the anti-fog laminate described in Patent Document 1 leaves room for improvement in terms of scratch resistance.

In view of the above circumstances, an object of one aspect of the present disclosure is to provide an anti-fog laminate having excellent scratch resistance and a method for producing the same.

Means for solving the above problems include the following aspects.
<1> A step of applying a photocurable composition onto a substrate to form a coating layer;
placing a light-transmitting film on the coating layer;
a step of irradiating the coating layer with light through the light-transmitting film to cure the coating layer to obtain a cured layer;
A method for producing an anti-fogging laminate comprising the steps of:
<2> The method for producing an anti-fogging laminate according to <1>, wherein the step of disposing the light-transmitting film includes a step of removing gas present between the light-transmitting film and the coating layer.
<3> The method for producing an anti-fogging laminate according to <1> or <2>, wherein the light-transmitting film has an average transmittance of 40% or more in a wavelength region of 200 nm to 500 nm.
<4> The method for producing an anti-fogging laminate according to any one of <1> to <3>, wherein the photocurable composition contains a polyfunctional monomer having two or more (meth)acryloyl groups, inorganic particles, and a surfactant.
<5> A substrate,
A cured material layer disposed on the substrate;
Equipped with
The anti-fogging laminate has a microindentation hardness of 0.080 GPa or more measured from the cured layer side.

According to one aspect of the present disclosure, an anti-fog laminate having excellent scratch resistance and a method for producing the same are provided.

In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the amount of each component contained in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.
In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present disclosure, the term "light" is a concept that encompasses active energy rays such as ultraviolet light and visible light.

In this disclosure, "(meth)acrylate" means acrylate or methacrylate, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylic" means acrylic or methacrylic.

[Method for producing anti-fogging laminate]
The method for producing the anti-fogging laminate of the present disclosure includes the steps of:
A step of applying a photocurable composition onto a substrate to form a coating layer (hereinafter also referred to as a "coating layer forming step");
A step of disposing a light-transmitting film on the coating layer (hereinafter also referred to as a "light-transmitting film disposing step");
a step of irradiating the coating layer with light through a light-transmitting film to cure the coating layer to obtain a cured layer (hereinafter also referred to as a "curing step");
has.
The method for producing the anti-fogging laminate of the present disclosure may include other steps as necessary.

According to the method for producing an anti-fog laminate of the present disclosure, an anti-fog laminate having excellent scratch resistance can be produced.
The reason why such an effect is achieved is believed to be that the polymerization inhibition caused by oxygen is suppressed by curing the coating layer formed using the photocurable composition by irradiating light through a light-transmitting film, and as a result, a cured layer having excellent hardness (i.e., scratch resistance) is formed on the substrate. The formed cured layer also has antifogging properties, and as a result, an antifogging laminate having excellent scratch resistance is produced.

Below, we will explain each step that may be included in the manufacturing method of the anti-fog laminate disclosed herein.

<Coating Layer Forming Step>
The coating layer forming step is a step of forming a coating layer by applying a photocurable composition onto a substrate.

(Base material)
The substrate is not particularly limited.
Examples of the substrate include:
Inorganic substrates made of inorganic materials such as glass, silica, metals, and metal oxides;
organic substrates made of organic materials such as polymethyl methacrylate (PMMA), polycarbonate, polyallyl carbonate, polyethylene terephthalate, polyacetyl cellulose (TAC), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene, polypropylene, polystyrene, polyurethane resin, epoxy resin, poly(meth)acrylate resin, vinyl chloride resin, silicone resin, paper, and pulp;
an organic/inorganic composite substrate made of an organic/inorganic composite material (e.g., SMC (Sheet Molding Compound), BMC (Bulk Molding Compound)) in which an unsaturated polyester resin and an inorganic filler (e.g., glass fiber, calcium carbonate, etc.) are combined;
etc.
The shape of the substrate is not particularly limited, and may be a plate shape, a lens shape, or the like.
In the present disclosure, the plate-shaped base material is also referred to as a "substrate."

The substrate may be a substrate formed by combining a plurality of members.
Examples of the substrate formed by combining a plurality of members include:
A laminated substrate formed by laminating a plurality of substrates;
a coated substrate having a coating (e.g., an undercoat layer) provided on a substrate;
A substrate that satisfies both of these requirements (i.e. a coated laminate substrate);
etc.

The undercoat layer may include a primer layer, an undercoat layer, an anchor coat layer, and the like.
The undercoat layer can be formed by using a coating agent.
As the coating agent, for example, a known coating agent containing a resin as a main component can be used.
Examples of the resin include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth)acrylic resins, polyvinyl acetate resins,
Examples of the resin include polyolefin resins (for example, polyethylene, polypropylene, ethylene-propylene copolymers, etc.), cellulose resins, etc.
The thickness of the undercoat layer is, for example, 0.5 μm to 10 μm.

The surface of the substrate may be subjected to an activation treatment, if necessary.
Examples of activation treatments include corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, flame treatment, and the like.

The method for producing the anti-fogging laminate of the present disclosure may further include a substrate preparation step of preparing the substrate (e.g., a laminate substrate with a coating film, etc.) described above prior to the coating layer formation step.

(Photocurable composition)
As the photocurable composition, a known photocurable composition can be used.
The photocurable composition is
A polyfunctional monomer having two or more (meth)acryloyl groups (hereinafter also referred to as “polyfunctional monomer (a1)”),
Inorganic particles (hereinafter also referred to as “inorganic particles (a2)”),
A surfactant (hereinafter also referred to as “surfactant (a3)”),
It is preferred that the compound contains
When a cured layer is formed using the photocurable composition of a preferred embodiment, the surfactant is stored in the cured layer and gradually seeps out to the surface of the cured layer, resulting in the cured layer exhibiting anti-fogging properties.

-Polyfunctional monomer (a1)-
The photocurable composition preferably contains at least one polyfunctional monomer (a1) (that is, a polyfunctional monomer having two or more (meth)acryloyl groups).
The polyfunctional monomer (a1) is polymerized when the photocurable composition is irradiated with light, and forms a network structure that serves as the basic skeleton of the cured layer. This causes the coating layer to harden and convert it into a cured layer. In the obtained cured layer, a space in which the surfactant is stored is formed as a gap in the network structure.

The polyfunctional monomer (a1) preferably comprises two or more (meth)acryloyl groups and a linker moiety that fixes these two or more (meth)acryloyl groups within one molecule.
The polyfunctional monomer (a1) is preferably an ester of (meth)acrylic acid and a polyhydric alcohol having two or more hydroxyl groups.
Here, examples of the "polyhydric alcohol having two or more hydroxyl groups" include:
Alkane polyols such as alkane diols and alkane triols;
Compounds containing a polyoxyalkylene structure, such as polyalkylene glycols (e.g., polyethylene glycol, polypropylene glycol, etc.) and compounds obtained by adding polyalkylene glycol to alkane polyol;
etc.
The "polyhydric alcohol having two or more hydroxyl groups" may contain an aromatic ring and/or an aliphatic ring. Examples of the "polyhydric alcohol having two or more hydroxyl groups" containing an aromatic ring include ethylene oxide adducts of bisphenols.

As a "polyhydric alcohol having two or more hydroxyl groups", a compound containing a polyoxyalkylene structure is preferred, and a diol containing a polyoxyethylene structure is more preferred.

Specific examples of the polyfunctional monomer (a1) include compounds represented by the following formula (1) or (2).
The polyfunctional monomer (a1) preferably contains a compound represented by the following formula (1).

In formula (1), n represents an integer of 1 to 30.
In formula (2), l and m are numbers such that l+m is an integer of 2 to 40.

Specific examples of the polyfunctional monomer (a1) include polyethylene glycol diacrylate and 2,2-bis-[4-(acryloxy-polyethoxy)phenyl]-propane.
Examples of the polyethylene glycol di(meth)acrylate include tetradecaethylene glycol di(meth)acrylate and tricosaethylene glycol di(meth)acrylate.

The polyfunctional monomer (a1) that can be contained in the photocurable composition may be one type alone or two or more types in combination.
The content of the polyfunctional monomer (a1) in the photocurable composition is preferably 30% by mass to 70% by mass, more preferably 35% by mass to 60% by mass, based on the total dry mass of the photocurable composition.

In this disclosure, the "total dry weight" of a composition means the combined weight of all components in the composition other than the solvent.

The content of the polyfunctional monomer (a1) in the photocurable composition is preferably 10% by mass to 50% by mass, more preferably 15% by mass to 35% by mass, based on the total amount of the photocurable composition.

--Inorganic particles (a2)--
The photocurable composition preferably contains at least one type of inorganic particles (a2).
The inorganic particles (a2) play a role in imparting appropriate hardness and strength to the cured product layer.
As the inorganic particles (a2), particles containing an inorganic substance are preferred, and particles consisting essentially of an inorganic substance are more preferred.
Examples of inorganic substances include silica, zirconia, alumina, metal oxides such as tin oxide, antimony oxide, and titania, as well as nanodiamond.
Among these, silica or zirconia is particularly preferred from the viewpoints of dispersibility in resin, hardness, light resistance, and the like.

The particle size of the inorganic particles (a2) is preferably from 5 nm to 50 nm, and more preferably from 10 nm to 30 nm.
When the particle size of the inorganic particles (a2) is 5 nm or more, it is advantageous from the viewpoint of the hardness of the cured film and dispersibility in the cured film.
When the particle size of the inorganic particles (a2) is 50 nm or less, it is advantageous from the viewpoint of the transparency of the cured film.
The particle size of the inorganic particles (a2) herein means a value determined by a dynamic scattering method using laser light.

The inorganic particles (a2) may contain a trace amount of an organic substance to the extent that it does not affect the inorganic substance or the physical properties of the inorganic particles (a2).
For example, the inorganic particles (a2) may be inorganic particles modified with a functional group containing a (meth)acryloyl group (hereinafter, also referred to as inorganic particles (a2-1)).
When the photocurable composition contains inorganic particles (a2-1), the (meth)acryloyl group in the inorganic particles (a2-1) may react with the (meth)acryloyl group in the polyfunctional monomer (a1) when the photocurable composition is cured. As a result, the inorganic particles (a2-1) are integrated with the network structure formed by the polyfunctional monomer (a1). This further improves the scratch resistance and antifogging properties of the cured film.
Particularly preferred inorganic particles (a2-1) are silica particles modified with a functional group containing a (meth)acryloyl group, or zirconia particles modified with a functional group containing a (meth)acryloyl group.

When the photocurable composition contains inorganic particles (a2-1), the proportion of inorganic particles (a2-1) in the total amount of inorganic particles (a2) contained in the photocurable composition is preferably 30% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and even more preferably 70% by mass to 100% by mass.

The inorganic particles (a2-1) are also available as commercial products.
An example of a commercially available product of silica particles modified with a functional group containing a (meth)acryloyl group is organosilica sol PGM-AC-2140Y manufactured by Nissan Chemical Industries, Ltd.

The inorganic particles (a2) that can be contained in the photocurable composition may be one type alone or two or more types in combination.
The content of the inorganic particles (a2) in the photocurable composition is preferably 30% by mass to 70% by mass, more preferably 40% by mass to 60% by mass, based on the total dry mass of the photocurable composition.

The content of inorganic particles (a2) in the photocurable composition is preferably 10% by mass to 50% by mass, more preferably 20% by mass to 40% by mass, based on the total amount of the photocurable composition.

In the photocurable composition, the mass ratio of inorganic particles (a2) to polyfunctional monomer (a1) (i.e., mass ratio [inorganic particles (a2)/polyfunctional monomer (a1)]) is preferably 0.6 to 2.0, more preferably 0.8 to 1.6, and even more preferably 1.0 to 1.4.

--Surfactant (a3)--
The photocurable composition preferably contains at least one surfactant (a3).
The surfactant (a3) is stored in the cured film and gradually advances to the surface of the cured film, thereby imparting anti-fogging properties to the cured film.
The surfactant (a3) is not particularly limited as long as it can fulfill such a role, but it is preferable that the surfactant has a polyoxyalkylene structure.

When the surfactant (a3) has a polyoxyalkylene structure, it is preferable that the surfactant (a3) does not have a (meth)acrylic polymer structure.
That is, it is preferable that the surfactant (a3) does not have either a structure represented by the following formula (AC1) or a structure represented by the following formula (AC2):

In formula (AC1) and formula (AC2), R represents a hydrogen atom or a methyl group, and n represents an integer of 2 or more.

It is also preferred that the surfactant (a3) does not contain an unsaturated bond.

More specifically, the surfactant (a3) is preferably a surfactant containing a hydrocarbon group and a polyoxyalkylene structure.
The hydrocarbon group is preferably an alkyl group.
The polyoxyalkylene structure may be a structure in which oxyalkylene groups are repeated. The oxyalkylene group is preferably -O-CH ₂ CH ₂ -, -O-CH ₂ CH ₂ CH ₂ -, or -O-CH ₂ CH ₂ CH ₂ CH ₂ -, and more preferably -O-CH ₂ CH ₂ -.
The number of oxyalkylene groups contained in the surfactant (a3) is preferably 1 to 30.

The surfactant (a3) preferably further contains an anionic hydrophilic group.
Examples of anionic hydrophilic groups include a sulfo group, a carboxy group, a phosphate group, an O-sulfate group (-O-SO ₃ ^- ), and an N-sulfate group (-NH-SO ₃ ^- ). Among these anionic hydrophilic groups, a phosphate group and an O-sulfate group (-O-SO ₃ ^- ) are preferred.
These anionic hydrophilic groups may be in the form of a free acid or a salt.
The salt is preferably a sodium salt, a potassium salt or an ammonium salt.

An example of a suitable surfactant (a3) is a compound represented by the following formula (SS1):

In formula (SS1), R represents an alkyl group having 10 to 20 carbon atoms or an alkenyl group having 10 to 20 carbon atoms, L represents an alkylene group having 2 to 4 carbon atoms, n represents an integer from 1 to 30, and X represents a hydroxyl group, a sulfo group, a phosphono group, a carboxy group, a phosphate group, an O-sulfate group, an N-sulfate group, a salt of a sulfo group, a salt of a phosphono group, a salt of a carboxy group, a salt of a phosphate group, a salt of an O-sulfate group, or a salt of an N-sulfate group.

In formula (SS1), examples of "-OL-" include -O-CH ₂ CH ₂ -, -O-CH ₂ CH ₂ CH ₂ -, -O-CH ₂ CH ₂ CH ₂ CH ₂ - and the like, and among these, -O-CH ₂ CH ₂ - is preferred.
In formula (SS1), X is more preferably a phosphate group, an O-sulfate group, a salt of a phosphate group, or a salt of an O-sulfate group.
The "salt" for X is preferably a sodium salt, a potassium salt, or an ammonium salt, and more preferably a sodium salt.

Among the surfactants (a3), examples of surfactants having an anionic hydrophilic group include polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkenyl ether sulfates, and mixtures thereof.
More specific examples of surfactants having an anionic hydrophilic group include polyoxyethylene oleyl cetyl ether sulfates such as sodium polyoxyethylene oleyl cetyl ether sulfate, and polyoxyethylene lauryl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate.

The surfactant (a3) may be a nonionic surfactant having a polyoxyalkylene structure.
Examples of nonionic surfactants having a polyoxyalkylene structure include polyoxyalkylene alkyl ethers such as polyoxyalkylene monoalkyl ethers, polyoxyalkylene alkenyl ethers such as polyoxyalkylene monoalkenyl ethers, and mixtures thereof.
Examples of the polyoxyalkylene alkyl ether include polyoxyalkylene branched decyl ether, polyoxyalkylene dodecyl ether (polyoxyalkylene lauryl ether), polyoxyalkylene tridecyl ether, and polyoxyalkylene oleyl cetyl ether.
The polyoxyalkylene alkyl ether is preferably a polyoxyethylene alkyl ether (for example, polyoxyethylene isodecyl ether, polyoxyethylene lauryl ether, etc.).

As the surfactant (a3), in addition to the surfactants described above, the surfactants described in paragraphs 0062 to 0069 of WO 2019/221268 may be used.

The surfactant (a3) that can be contained in the photocurable composition may be one type alone or two or more types in combination.
The content of the surfactant (a3) in the photocurable composition is preferably 1.0 mass % to 10 mass %, more preferably 2.0 mass % to 8.0 mass %, and even more preferably 3.0 mass % to 7.0 mass %, based on the total dry mass of the photocurable composition.

The content of the surfactant (a3) in the photocurable composition is preferably 0.5% by mass to 6.0% by mass, and more preferably 1.0% by mass to 5.0% by mass, based on the total amount of the photocurable composition.

- Photopolymerization initiator -
The photocurable composition preferably contains at least one photopolymerization initiator.
The photopolymerization initiator is preferably a photoradical polymerization initiator.
As the photoradical polymerization initiator, known photoradical polymerization initiators can be used.
Examples of the photoradical polymerization initiator include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, phenylglyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, anthraquinone compounds, etc. Among these, alkylphenone compounds and acylphosphine oxide compounds are preferred from the viewpoint of reactivity, etc.
As the photoradical polymerization initiator, a commercially available product can also be used.
Commercially available photoradical polymerization initiators include, for example:
Omnirad 127, 184, 1173, 500, 819, and TPO (all manufactured by IGM resins B.V.);
Esacure ONE, KIP100F, KT37, KTO46 (all manufactured by Lamberti);
etc.

The photopolymerization initiator that can be contained in the photocurable composition may be one type alone or two or more types in combination.
The content of the photopolymerization initiator in the photocurable composition is preferably 0.4% by mass to 10% by mass, more preferably 0.6% by mass to 6.0% by mass, and even more preferably 1.0% by mass to 4.0% by mass, based on the total dry mass of the photocurable composition.

The content of the surfactant (a3) in the photocurable composition is preferably 0.2% by mass to 6.0% by mass, more preferably 0.4% by mass to 4.0% by mass, and even more preferably 0.6% by mass to 3.0% by mass, based on the total amount of the photocurable composition.

-solvent-
The photocurable composition preferably contains at least one solvent.
As a solvent, for example:
Alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, n-pentanol, isopentanol, n-hexanol, n-octanol, 2-ethyl-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-n-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol (also known as propylene glycol monomethyl ether), 1-ethoxy-2-propanol, 1-n-propoxy-2-propanol, 1-isopropoxy-2-propanol, and cyclohexanol;
Ethers such as diethyl ether, tetrahydrofuran, and dioxane;
Nitriles such as acetonitrile;
Esters such as ethyl acetate, n-propyl acetate, and n-butyl acetate;
Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone;
Amides such as N,N-dimethylformamide and N,N-dimethylacetamide;
water;
etc.
Among these, alcohols, ketones, or mixed solvents of alcohols and ketones are preferred.

The content of the solvent in the photocurable composition is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more, based on the total amount of the photocurable composition.
The upper limit of the content of the solvent relative to the total amount of the photocurable composition varies depending on the amounts of other components, but is, for example, 80% by mass, preferably 70% by mass, and more preferably 60% by mass.

The photocurable composition may contain other components in addition to the components described above.
For other components, please refer to the descriptions in paragraphs 0032 to 0163 of WO 2019/221268 as appropriate.

(Application method, etc.)
In the coating layer forming step, a photocurable composition is applied onto a substrate to form a coating layer.
The photocurable composition can be applied by any conventional method.
Examples of the coating method include bar coating, spin coating, dip coating, spray coating, flow coating, brush coating, gravure coating, reverse roll coating, knife coating, and kiss coating.
In the coating layer forming step, the photocurable composition may be applied onto a substrate, and the applied photocurable composition may be dried (for example, dried by heating) to form the coating layer.

<Light-transmitting film arrangement process>
The light-transmitting film disposing step is a step of disposing a light-transmitting film on the coating layer.
In the curing step described below, the coating layer is irradiated with light through a light-transmitting film, and the irradiated light cures the coating layer to obtain a cured layer.
In the method for producing an anti-fog laminate disclosed herein, the coating layer is irradiated with light through a light-transmitting film. This suppresses inhibition of radical polymerization by oxygen compared to when the coating layer is irradiated with light directly without using a light-transmitting film, and as a result, a cured layer with excellent hardness is obtained.

There are no particular limitations on the light-transmitting film, so long as it is a film having light-transmitting properties.
Here, having optical transparency means a property in which the average transmittance in the wavelength region of 200 nm to 500 nm is 10% or more.
The light-transmitting film preferably has an average transmittance of 40% or more in the wavelength region of 200 nm to 500 nm.

The thickness of the light-transmitting film is preferably 1 μm to 100 μm, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm.

The light-transmitting film is not particularly limited, but examples thereof include polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polyethylene (PE) film, polypropylene (PP) film, polycarbonate (PC) film, polystyrene (PS) film, polyvinyl chloride (PVC) film, polyvinylidene chloride (PVDC) film, polyvinyl alcohol (PVA) film, nylon film, polyacrylonitrile film, ethylene-methacrylic acid copolymer film, ethylene-vinyl alcohol copolymer film, ethylene-vinyl acetate copolymer film, cellophane, and the like.
As the light-transmitting film, a PET film is particularly preferable.

The light-transmitting film disposing step may include a step of removing gas present between the light-transmitting film and the coating layer, which further suppresses inhibition of radical polymerization caused by oxygen, thereby obtaining a cured layer having superior hardness.
As a method for removing the gas present between the light-transmitting film and the coating layer, a known method can be applied.
As the above-mentioned method, for example, a method can be applied in which, with a light-transmitting film placed on the coating layer, pressure is applied to at least one side of the substrate and the light-transmitting film with a roller or the like, while removing the gas present between the light-transmitting film and the coating layer.

<Curing process>
The curing step is a step in which the coating layer is irradiated with light through a light-transmitting film to cure the coating layer, thereby obtaining a cured layer.
The wavelength range of the irradiated light is, for example, from 0.0001 nm to 800 nm.
More specifically, examples of the light to be irradiated include α-rays, β-rays, γ-rays, X-rays, electron beams, ultraviolet rays, visible light, etc., with ultraviolet rays being preferred.
The peak wavelength of the ultraviolet light is preferably 200 nm to 450 nm, more preferably 230 nm to 445 nm, even more preferably 240 nm to 430 nm, and still more preferably 250 nm to 400 nm.

The light irradiation energy is preferably 10 mJ/cm ² to 1000 mJ/cm ² , and more preferably 50 mJ/cm ² to 500 mJ/cm ² .

<Peeling process>
The method for producing the anti-fog laminate of the present disclosure may further include, after the curing step, a peeling step of peeling the light-transmitting film from the cured product layer.
The peeling step exposes the surface of the cured layer, which exhibits anti-fogging properties and scratch resistance.

The method for producing the anti-fogging laminate of the present disclosure does not necessarily have to include a peeling step.
Even in this case, an anti-fog laminate with a light-transmitting film can be produced by the method for producing an anti-fog laminate of the present disclosure. The anti-fog laminate with a light-transmitting film can be used by peeling the light-transmitting film from the cured product layer immediately before use, as necessary.

[Anti-fogging laminate]
The anti-fogging laminate of the present disclosure comprises:
A substrate;
A cured material layer disposed on a substrate;
Equipped with
The anti-fogging laminate has a microindentation hardness of 0.080 GPa or more as measured from the cured layer side.
The anti-fogging laminate of the present disclosure may include other elements as necessary.

The anti-fog laminate of the present disclosure is preferably produced by the above-mentioned method for producing the anti-fog laminate of the present disclosure.
The cured layer is preferably a layer formed by irradiating a coating layer of a photocurable composition with light.

<Microindentation hardness>
The anti-fogging laminate of the present disclosure has a microindentation hardness of 0.080 GPa or more measured from the cured product layer side.
For this reason, the anti-fog laminate of the present disclosure has excellent scratch resistance. The anti-fog laminate of the present disclosure also has excellent anti-fog properties (particularly, anti-fog properties against steam).

As described above, according to the method for producing an anti-fog laminate of the present disclosure, which includes a light-transmitting film arrangement step and a curing step, a cured layer with excellent hardness can be formed, making it easier to produce an anti-fog laminate having the above-mentioned microindentation hardness.
In addition to the above-mentioned production method, for example:
Increasing the amount of inorganic particles;
Improve the crosslinkability of the cured product (for example, by using a polyfunctional monomer having a large number of (meth)acryloyl groups, by reducing the molecular weight per (meth)acryloyl group, etc.);
By the above method, the microindentation hardness value (GPa) can be adjusted to be high.
The reason why a microindentation hardness of 0.080 GPa or more provides excellent scratch resistance and also excellent anti-fogging properties (particularly anti-fogging properties against steam) is presumed to be as follows.
By having a microindentation hardness of 0.080 GPa or more, the cured layer has a dense structure, which is easily maintained when subjected to an external impact, improving the scratch resistance. Furthermore, the dense structure improves the sustained release of hydrophilic groups (e.g., those derived from surfactants) in the structure, and is considered to improve the anti-fogging durability against the above in particular.

The microindentation hardness is preferably 0.080 GPa to 0.50 GPa, and more preferably 0.080 GPa to 0.15 GPa.
When the microindentation hardness of the anti-fogging laminate of the present disclosure is 0.50 GPa or less, the resistance to cracking and the initial anti-fogging properties are further improved.

In the present disclosure, the microindentation hardness is measured in accordance with ISO 14577. Specifically, it is measured as follows.
A Berkovich indenter is used as the measuring indenter, and a load is applied from the cured layer side of the anti-fogging laminate under the conditions of maximum load (Pmax): 10 mN, maximum indentation depth: 1000 nm, loading speed: 800 to 12000 μN/sec, loading time: 1 second (load holding time after reaching the maximum load), and creep time: 0.5 second, to obtain a load-displacement curve.
From the obtained load-displacement curve, the contact stiffness (S) and maximum displacement (hmax) are calculated. Furthermore, the contact depth (hc) is calculated from the following formula (1), the contact projected area (Ac) is calculated from the following formula (2), and the microindentation hardness (H) is calculated from the following formula (3).
As a measuring device for the microindentation hardness, for example, HYSITRON TI PREMIER manufactured by Bruker Corporation can be used.

S: Contact stiffness P _max : Maximum load h _max : Maximum displacement h _c : Contact depth ε: Constant related to the indenter shape (0.75 for Berkovich indenter)
A _c : Contact projected area H: Microindentation hardness

<Substrate>
The anti-fog laminate of the present disclosure includes a substrate.
For specific examples and preferred embodiments of the substrate, please refer to the section "Method of manufacturing anti-fogging laminate" as appropriate.

<Cured Layer>
From the viewpoint of anti-fogging properties, the cured product layer preferably contains a resin, inorganic particles, and a surfactant.
For preferred embodiments of the inorganic particles and surfactant that can be contained in the cured product layer, please refer to the sections "Method for producing anti-fogging laminate" (description of inorganic particles (a2) and surfactant (a3)), as appropriate.
The preferred range of the content of the inorganic particles relative to the total amount of the cured product layer is the same as the preferred range of the content of the inorganic particles (a2) relative to the total dry mass of the photocurable composition,
The preferred range of the content of the surfactant relative to the total amount of the cured product layer is the same as the preferred range of the content of the surfactant (a3) relative to the total dry mass of the photocurable composition.

The resin that can be contained in the cured material layer is preferably a (meth)acrylic resin having a network structure, and more preferably a polyfunctional monomer having two or more (meth)acryloyl groups.
For preferred embodiments of the polyfunctional monomer having two or more (meth)acryloyl groups, please refer to the section entitled "Method for producing anti-fogging laminate" (description of polyfunctional monomer (a1)).
The preferred range of the resin content relative to the total amount of the cured product layer is the same as the preferred range of the polyfunctional monomer (a1) content relative to the total dry mass of the photocurable composition.

(Thickness of the cured layer)
The thickness of the cured layer is preferably 4 μm or more, more preferably 6 μm or more, and further preferably 10 μm or more.
When the thickness of the cured product layer is 4 μm or more, the anti-fog laminate has better anti-fog properties and anti-fog durability. In this case, for example, the anti-fog laminate exhibits excellent anti-fog properties even after being washed with water.
There is no particular upper limit to the thickness of the cured layer.
From the viewpoints of ease of production (eg, coatability) and appearance of the cured material layer, the cured material layer is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

(Water contact angle)
The contact angle of water on the surface of the cured layer (after 1 second) is preferably 30° or less, more preferably 25° or less, and even more preferably 23° or less.
There is no particular lower limit to the water contact angle (after 1 second) on the surface of the cured layer, but examples of the lower limit include 5.0°, 10.0°, and 15.0°.
Here, the contact angle of water (after 1 second) means the contact angle after 1 second from when a droplet of pure water having a volume of 1.0 μL lands on the surface of the cured material layer.

The contact angle of water on the surface of the cured layer (after 22 seconds) is preferably 14.0° or less, and more preferably 13.5° or less.
There is no particular lower limit to the contact angle of water (after 22 seconds) on the surface of the cured layer, but examples of the lower limit include 5.0° and 10.0°.
Here, the contact angle of water (after 22 seconds) means the contact angle 22 seconds after a droplet of pure water having a volume of 1.0 μL lands on the surface of the cured material layer.

<Other elements>
The anti-fog laminate of the present disclosure may include a light-transmitting film on the cured product layer.
The anti-fog laminate having a light-transmitting film is used, for example, by peeling (removing) the light-transmitting film from the cured material layer immediately before obtaining the anti-fog effect of the cured material layer.

The anti-fogging laminate of the present disclosure may also include an adhesive layer on the side opposite to the side on which the cured product layer is disposed, as viewed from the substrate.
The anti-fogging laminate having an adhesive layer is, for example, attached to various objects and used to impart anti-fogging properties to the objects. The objects are not particularly limited, but examples thereof include:
Exterior walls of vehicles or buildings;
Windows in vehicles or buildings;
Mirrors in bathrooms etc.;
Surfaces of display devices such as computer displays, mobile phone displays, and televisions;
Information boards such as signs, advertisements, and guide boards;
Railway, road, etc. signs;
etc.

The adhesive layer includes an adhesive.
The adhesive is not particularly limited, and any known adhesive can be used.
Examples of the adhesive include an acrylic adhesive, a rubber adhesive, a vinyl ether polymer adhesive, and a silicone adhesive.
The thickness of the adhesive layer is preferably 2 μm to 50 μm, and more preferably 5 to 30 μm.

<Applications>
The anti-fog laminate of the present disclosure can be suitably used as an anti-fog material, an anti-fouling material, a quick-drying material, an anti-condensation material, an anti-static material, and the like.
The anti-fog laminate of the present disclosure may be, for example:
Optical articles such as optical films, optical discs, optical lenses, eyeglass lenses, spectacles, sunglasses, goggles, helmet shields, headlamps, taillamps, window glass (e.g., window glass of vehicles and buildings, etc.);
The material of these optical components;
The present invention can be applied to various applications such as the above.
The anti-fog laminate of the present disclosure can also be applied to, for example, image recognition systems using on-board cameras, which have become widely installed in vehicles in recent years.

The following are examples of the present disclosure, but the present disclosure is not limited to the following examples.

Example 1
<Preparation of Photocurable Composition>
Under normal temperature and pressure conditions, a surfactant (a3) and inorganic particles (a2) shown in Table 1 were added to a glass screw tube bottle in amounts corresponding to the mass contents shown in Table 1. A solvent shown in Table 1 was then added, and the mixture was stirred using a magnetic stirrer and a stirring bar until the surfactant was completely dissolved.
Next, to the stirred glass screw-top bottle, polyfunctional monomer (a1) shown in Table 1 was added in an amount corresponding to the mass content shown in Table 1, and thoroughly stirred until compatible. Then, to the stirred glass screw-top bottle, photopolymerization initiator shown in Table 1 was added in an amount corresponding to the mass content shown in Table 1, and stirred until completely dissolved, to obtain a photocurable composition that is a liquid composition.

<Preparation of Anti-Fog Laminate>
(Preparation of substrate)
A laminated substrate was prepared by attaching a PET film ("Lumirror U483" manufactured by Toray Industries, Inc.) onto a polycarbonate substrate.
A primer composition (Takelac (registered trademark) WS-5100) was applied to the surface of the PET film side of the laminated substrate with a bar coater to form a primer layer, thereby obtaining a laminated substrate with a primer layer (layer structure: "primer layer/PET film/polycarbonate substrate").

(Coating layer forming process)
The above-mentioned photocurable composition was applied onto the primer layer of the primer layer-formed laminate substrate as the base material using a bar coater to form a coating layer (coating layer forming step).

(Light-transmitting film placement process)
A light-transmitting film (polyethylene terephthalate, T-15 (product name), thickness 37 μm, average transmittance from 200 nm to 500 nm 53.5%, manufactured by Mitsui Chemicals Tocello Co., Ltd.) was placed on the coating layer, and gas present between the light-transmitting film and the coating layer was removed using a rolling roller.

(Curing process)
Next, the coating layer was irradiated with ultraviolet light (UVA) through a light-transmitting film at 210 mJ/cm ⁻² to harden the coating layer, thereby converting it into a hardened layer.
Next, the light-transmitting film (T-15) was peeled off from the cured layer.
As a result of the above, an anti-fogging laminate was obtained that included a substrate (i.e., a substrate having a laminate structure represented by "primer layer/PET film/polycarbonate") and a cured product layer disposed on the substrate.
The anti-fogging laminate had a laminate structure represented by "cured material layer/primer layer/PET film/polycarbonate substrate".

<Evaluation>
The above antifogging laminate was subjected to the following evaluations.
The results are shown in Table 1.

(Thickness of the cured layer)
Using a film thickness measuring device (ETA-ARC, manufactured by OPTOTECH), the spectral reflectance was measured near the center of the cured material layer in the anti-fogging laminate, and the film thickness of the cured material layer was calculated from the obtained spectral reflectance by the Fourier transform method.

(Abrasion resistance of anti-fog laminate)
Using steel wool #0000, the anti-fogging laminate was placed on the steel wool in such a manner that the cured layer was in contact with the steel wool, and a weight of 300 g or 1 kg was placed directly on the anti-fogging laminate to apply a load. In this state, the anti-fogging laminate was reciprocated 10 times on the steel wool. This reciprocation was performed using a No. 428 Gakushin type abrasion tester (friction tester type II) (manufactured by Yasuda Seiki Seisakusho Co., Ltd.).
After the reciprocating motion, the anti-fog laminate was visually inspected for the presence or absence of scratches, the state of the scratches (depth, number, etc.), and the remaining state of the cured layer, and the scratch resistance of the anti-fog laminate was evaluated based on the following evaluation criteria.
In the following evaluation criteria, rank 5 is the most excellent rank in scratch resistance.
In addition, in Table 1 described later, ranks expressed as decimals, such as "2.5", represent an evaluation between ranks 2 and 3.

--Evaluation Criteria for Scratch Resistance of Anti-Fog Laminate--
5: The surface of the cured layer is almost free of visible scratches, and the cured layer remains over the entire surface.
4: The surface of the hardened layer has several to ten thin scratches, and the hardened layer remains entirely.
3: The surface of the hardened layer had several to ten thick scratches, and the hardened layer remained entirely.
2: A state in which the surface of the hardened layer has deep scratches in an area corresponding to the entire width of the steel wool, but part of the hardened layer remains.
1: A state in which the surface of the hardened material layer has deep scratches in an area corresponding to the entire width of the steel wool, and the hardened material layer has peeled off entirely.

(Anti-fogging properties)
(Breath-proof)
Breath was blown onto the cured material layer of the anti-fogging laminate for several seconds, and the presence or absence of fogging on the surface of the cured material layer was visually confirmed.
Based on the observation results, the breath anti-fogging properties were evaluated according to the following evaluation criteria.
In the following evaluation criteria, if the rating is A, the breath anti-fogging property is excellent.

-Evaluation criteria for breath anti-fogging properties-
A: When breath was blown onto the surface of the cured layer for several seconds, no clouding occurred on the surface of the cured layer.
B: When breath was blown onto the surface of the cured layer for several seconds, the surface became cloudy.

(50°C steam anti-fogging property)
Pure water was placed in a beaker and heated to 50°C.
After the temperature of the pure water in the beaker reached 50° C., the anti-fog laminate was placed on the top of the beaker with the cured layer in contact with water vapor, and this state was maintained for 1 hour. During the 1-hour maintenance, the anti-fog laminate was visually observed to check for the presence or absence of fogging, and the 50° C. steam anti-fog property was evaluated according to the following evaluation criteria.
In the following evaluation criteria, the most excellent rank for 50° C. steam anti-fogging property is A.

-50℃ steam anti-fogging evaluation criteria-
A: At the completion of the 1-hour retention period, no clouding occurred on the surface of the cured layer.
B: At the completion of the 1-hour retention period, the surface of the cured material layer became cloudy, but at the completion of the 0.5-hour retention period, the surface of the cured material layer became cloudy.
C: At the completion of the 0.5 hour retention time, the surface of the cured layer became cloudy.

(Contact angle)
The contact angle of pure water on the surface of the cured layer of the laminate was measured using a contact angle meter (Automatic Contact Angle Meter CA-V Type, manufactured by Kyowa Interface Science Co., Ltd.) Measurements were performed at three locations per sample, and the average of these values was taken as the contact angle value.
The contact angle was measured 1 second after a 1.0 μL droplet of pure water landed on the substrate, and 22 seconds after a 1.0 μL droplet of pure water landed on the substrate. The smaller the contact angle, the better the anti-fogging properties.

<Microindentation hardness>
For the photocurable composition of Example 1, an anti-fogging laminate comprising a substrate (i.e., a substrate having a laminate structure represented by "primer layer/PET film/magnetic stainless steel substrate") and a cured product layer disposed on the substrate was obtained in the same manner as described in <Preparation of anti-fogging laminate> above, except that a magnetic stainless steel substrate was used instead of polycarbonate in order to attach the composition to a measuring device described below.
The anti-fogging laminate had a laminate structure represented by "cured material layer/primer layer/PET film/magnetic stainless steel substrate".
The microindentation hardness of the obtained antifogging laminate was measured by the above-mentioned method.
The measurement device used was a HYSITRON TI PREMIER manufactured by Bruker Corporation, and the measurement indenter used was a Varco Picher indenter.

Comparative Example 1
An anti-fog laminate was produced in the same manner as in Example 1, except that the light-transmitting film disposing step was omitted and the coating layer was directly irradiated with ultraviolet light (UVA) to form a cured layer.
The anti-fogging laminate thus obtained was subjected to evaluation of scratch resistance in the same manner as in Example 1.
In Comparative Example 1, the scratch resistance was extremely poor, so the evaluation of the antifogging properties and the measurement of the microindentation hardness were omitted.
The results are shown in Table 1.

Comparative Example 2
The composition of the photocurable composition was changed as shown in Table 1.
No primer layer was formed.
The coating method of the photocurable composition was changed to a spin coating method under the following conditions; and
An anti-fog laminate was produced in the same manner as in Example 1, except that the light-transmitting film disposing step was not carried out and the coating layer was directly irradiated with ultraviolet light (UVA) to form a cured layer.
The antifogging laminate thus obtained was evaluated in the same manner as in Example 1.
In addition, in the anti-fogging laminate used for measuring the microindentation hardness, a magnetic stainless steel substrate was used instead of the polycarbonate substrate, as in Example 1.
The results are shown in Table 1.

--Spin Coating Conditions (Comparative Example 2)--
While a laminate substrate (i.e., a PET film/polycarbonate substrate) serving as a base material was rotated at a rotation speed of 500 rpm (revolutions per minute) for 10 seconds, a photocurable composition was dropped onto the surface of the laminate substrate on the PET film side, and then the rotation speed of the laminate substrate was increased to 1000 rpm and rotated for 10 seconds to spread the photocurable composition and form a coating layer.

In Table 1, "mass % in composition" means the content (mass %) of the corresponding component relative to the total amount of the photocurable composition, and "dry mass %" means the content (mass %) of the corresponding component relative to the total dry mass of the photocurable composition (i.e., the total mass of components other than the solvent).
In Table 1, "-" means that the corresponding component is not contained.
In Table 1, the "solid content" for the amount of inorganic particles (a2) refers to the mass of components other than the solvent contained in the mass of the sol when the inorganic particles (a2) are used in the form of a corresponding sol.

Details regarding the terms used in Table 1 are as follows:
-Polyfunctional monomer (a1)-
A-600: Polyethylene glycol #600 diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
--Inorganic particles (a2)--
PGM-AC-2140Y: Organosilica sol (surface modified grade of propylene glycol monomethyl ether dispersed silica sol: silica particle content 42% by mass; particle size 10 to 15 nm; manufactured by Nissan Chemical Industries, Ltd.)
--Surfactant (a3)--
Noigen LP-100...Polyoxyalkylene lauryl ether (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
- Photopolymerization initiator -
Omnirad 127 (2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one; manufactured by IGM resins B.V.)
-solvent-
DEGDME: Diethylene glycol dimethyl ether PGME: Propylene glycol monomethyl ether

As shown in Table 1, in Example 1 in which the light-transmitting film disposing step was carried out, an anti-fog laminate having anti-fog properties and excellent scratch resistance could be produced.
In contrast, in Comparative Examples 1 and 2 in which the light-transmitting film disposing step was not carried out, the scratch resistance of the anti-fog laminate decreased.

Claims (3)

A step of applying a photocurable composition onto a substrate to form a coating layer;
placing a light-transmitting film on the coating layer;
a step of irradiating the coating layer with light through the light-transmitting film to cure the coating layer to obtain a cured layer;
having
The photocurable composition contains a polyfunctional monomer having two or more (meth)acryloyl groups, inorganic particles, and a surfactant,
The method for producing an anti-fogging laminate , wherein the surfactant comprises a compound represented by the following formula (SS1) :



In formula (SS1), R represents an alkyl group having 10 to 20 carbon atoms, L represents an alkylene group having 2 to 4 carbon atoms, n represents an integer from 1 to 30, and X represents a hydroxyl group, a sulfo group, a phosphono group, a carboxy group, a phosphate group, an O-sulfate group, an N-sulfate group, a salt of a sulfo group, a salt of a phosphono group, a salt of a carboxy group, a salt of a phosphate group, a salt of an O-sulfate group, or a salt of an N-sulfate group.
The method for producing an anti-fog laminate according to claim 1, wherein the step of disposing the light-transmitting film includes a step of removing gas present between the light-transmitting film and the coating layer. The method for producing an anti-fog laminate according to claim 1 or 2, wherein the light-transmitting film has an average transmittance of 40% or more in the wavelength range of 200 nm to 500 nm.