JP7709940B2 - Releaseable laminate, and transfer sheet, process sheet, and article using same - Google Patents

Description

The present invention relates to a release laminate, as well as a transfer sheet, a process sheet, and an article using the same.

In recent years, electronic device components have become increasingly miniaturized, and so a manufacturing method for these components is being adopted in which various electronic device components are glued and fixed onto a film, and after processes such as cutting and punching are completed, each component is peeled off from the film and used. This type of film is called a "process film" and is primarily used in the manufacture of ceramic green sheets.

For example, Patent Document 1 has proposed such a process film.

JP 2002-64131 A

The process film of Patent Document 1 imparts initial adhesion with an adhesive layer formed on the film, while after the process is completed, the adhesive layer is hardened by exposure to ionizing radiation to reduce adhesion, and the film is further heated to thermally shrink, allowing parts, etc. to be easily peeled off from the adhesive layer.
However, the process film of Patent Document 1 requires irradiation with ionizing radiation and heating, which makes the process complicated and requires two pieces of equipment (an equipment for irradiating ionizing radiation and an equipment for heating), which is not economical.
In addition, a process film has been proposed that allows parts, etc. to be peeled off by only irradiating them with ionizing radiation or by heating them after the process is completed, but this still requires ionizing radiation irradiation equipment or heating equipment.

As described above, conventional process films have had problems with operational efficiency when peeling off parts and the like adhered to the film after the process is completed.
Furthermore, not only for process films, but also for other members that have a certain adhesive strength to pressure-sensitive adhesives but can be easily peeled off, have not been proposed.

The present invention was made in consideration of these circumstances, and aims to provide a release laminate that has a certain adhesive strength to a pressure-sensitive adhesive while being easily peelable, as well as a transfer sheet, a process sheet, and an article that use the same.

In order to solve the above problems, the present invention provides the following [1] to [4].
[1] A laminate having a release layer on a transparent plastic film, the release layer being located on the outermost surface of the laminate, and satisfying the following conditions 1 and 2:
<Condition 1>
Prepare an adhesive tape A having a peel strength of PA (N/10 mm) according to method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate). When the adhesive tape A is attached to the surface of the release layer side of a release laminate and the adhesive tape A is peeled in accordance with method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength is expressed as P1 (N/10 mm), and P1/PA is 0.75 or more.
<Condition 2>
Adhesive tape A is attached to the surface of the release layer side of the release laminate. Water is dropped with a dropper so that at least the area of the surface of the release layer side of the release laminate where adhesive tape A is attached and the area 1 cm outside from the outer edge of adhesive tape A are covered with water. Five minutes after the completion of dropping water, when the adhesive tape A is peeled off in accordance with Method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength P2 (N/10 mm) shows P2/PA of 0.2 or less.
[2] A transfer sheet having a transfer layer on the release layer of the release laminate described in [1] above.
[3] A process sheet having a release layer of the release laminate described in [1] above as its outermost surface.
[4] An article in which the release layer of the release laminate according to [1] above is arranged so as to face the front surface.

The present invention provides a release laminate that has a certain adhesive strength to a pressure sensitive adhesive while allowing the adhered material to be easily peeled off by the simple process of dropping water, as well as a transfer sheet, process sheet, and article that use the same.

1 is a cross-sectional view showing one embodiment of a release laminate of the present invention. FIG. 2 is a cross-sectional view showing another embodiment of the release laminate of the present invention.

[Releasable laminate]
The release laminate of the present invention is a laminate having a release layer on a transparent plastic film, the release layer being located on the outermost surface of the laminate and satisfying the following conditions 1 and 2.
<Condition 1>
Prepare an adhesive tape A having a peel strength of PA (N/10 mm) according to method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate). When the adhesive tape A is attached to the surface of the release layer side of a release laminate and the adhesive tape A is peeled in accordance with method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength is expressed as P1 (N/10 mm), and P1/PA is 0.75 or more.
<Condition 2>
Adhesive tape A is attached to the surface of the release layer side of the release laminate. Water is dropped with a dropper so that at least the area of the surface of the release layer side of the release laminate where adhesive tape A is attached and the area 1 cm outside from the outer edge of adhesive tape A are covered with water. Five minutes after the completion of dropping water, when the adhesive tape A is peeled off in accordance with Method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength P2 (N/10 mm) shows P2/PA of 0.2 or less.

1 and 2 are cross-sectional views showing one embodiment of the release laminate of the present invention.
1 and 2 has a hard coat layer 20, a layer 30 containing an inorganic compound, and a release layer 40, in this order, on a transparent plastic film 10. Also, the release laminate 100 in FIG. 2 has a hard coat layer 20, a layer 30 containing an inorganic compound, and a release layer 40 on both sides of the transparent plastic film 10.
The release laminate of the present invention is not limited to the embodiment shown in Fig. 1 and Fig. 2. For example, the layer 30 containing an inorganic compound and/or the hard coat layer 20 may not be present between the transparent plastic film 10 and the release layer 40. The release layer 40 does not need to be formed on the entire surface of the transparent plastic film 10, and may be present on at least a part of the transparent plastic film 10. The release laminate may also have other layers not shown.

The release laminate of the present invention is required to satisfy the following condition 1.
<Condition 1>
Prepare an adhesive tape A having a peel strength of PA (N/10 mm) according to method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate). When the adhesive tape A is attached to the surface of the release layer side of a release laminate and the adhesive tape A is peeled in accordance with method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength is expressed as P1 (N/10 mm), and P1/PA is 0.75 or more.

Satisfying condition 1 indicates that the adhesive tape is sufficiently adhered to the surface of the release layer side of the release laminate.
In addition, satisfying condition 1 and also satisfying condition 2 described below indicates that the adhesive tape adheres sufficiently well in the initial stage, while the adhesive tape can be easily peeled off by the simple task of dripping water.

The pressure-sensitive adhesive tape A used under conditions 1 to 4 is preferably one having a peel strength of 3 to 7 (N/10 mm) according to method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate).
Examples of the adhesive of the adhesive tape A used under conditions 1 to 4 include a rubber-based adhesive, an acrylic-based adhesive, a urethane-based adhesive and a silicone-based adhesive. The substrate of the adhesive tape A is preferably a film.

To make it easier to satisfy condition 1, it is preferable to form the release layer from a material described below, to set the thickness of the release layer within the range described below, and to improve the adhesion between the release layer and the layer in contact with the release layer.

The release laminate of the present invention is required to satisfy the following condition 2.
<Condition 2>
Adhesive tape A is attached to the surface of the release layer side of the release laminate. Water is dropped with a dropper so that at least the area of the surface of the release layer side of the release laminate where adhesive tape A is attached and the area 1 cm outside from the outer edge of adhesive tape A are covered with water. Five minutes after the completion of dropping water, when the adhesive tape A is peeled off in accordance with Method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength P2 (N/10 mm) shows P2/PA of 0.2 or less.

Satisfying condition 2 means that the peel strength of an adherend such as an adhesive tape is reduced by an extremely simple process of dripping water and waiting for a short period of time, and the adherend such as an adhesive tape can be easily peeled off.
In Condition 2 and Conditions 3 and 4 described below, the water to be dropped is preferably ion-exchanged water.

The releasable substrate of the transfer sheet is required to have the property of having good adhesion to the transfer layer formed on the releasable substrate, and is also required to have the property of being easily peeled off from the transfer layer after the transfer layer has been transferred to the adherend.
Furthermore, the process sheet is required to have the property of being able to adhere and fix electronic components, etc. via an adhesive or the like, and also to have the property of being able to easily peel the electronic components, etc. from the surface of the process sheet after the process is completed.
Furthermore, in showcases, show windows and windows, the adhesive tape must be able to affix advertisements and other display items, and the adhesive tape must also be able to be easily peeled off when changing the displayed items.
Therefore, the release laminate of the present invention that satisfies conditions 1 and 2 is useful as a release substrate for a transfer sheet and a process sheet. It is also useful to apply the release laminate of the present invention to the surfaces of showcases, show windows and windows.

To make it easier to satisfy condition 2, it is preferable to form the release layer from the material described below and to set the thickness of the release layer within the range described below.

It is preferable that the release laminate of the present invention further satisfies the following condition 3.
<Condition 3>
The surface of the release layer of the release laminate is rubbed back and forth 1000 times with a cotton 300 number flannel cloth at a load of 500 g/ ^cm2 to obtain the friction laminate 1. The adhesive tape A is attached to the surface of the release layer side of the friction laminate 1. Water is dropped with a dropper so that at least the area where the adhesive tape A is attached and the area 1 cm outside the outer edge of the adhesive tape A are covered with water on the surface of the release layer side of the friction laminate 1. Five minutes after the water dropping is completed, the adhesive tape A is peeled off according to JIS Z0237:2009 method 1 except that the test plate is not stainless steel but the friction laminate 1, and the peel strength is P3 (N/10 mm), and P3/PA is 0.2 or less.

Condition 3 indicates that the characteristics of condition 2 are maintained even if the surface of the release layer is rubbed many times with a flannel cloth. In other words, satisfying condition 3 means that the characteristic of the adhesive strength of an adhesive such as an adhesive tape decreasing when water is dropped on it can be maintained for a long period of time.

The releasable substrate of the transfer sheet and the process sheet are usually discarded after one use. However, when condition 3 is satisfied, the property that reduces the adhesive strength of the adherend is not reduced by friction, which is preferable in that the releasable substrate of the transfer sheet and the process sheet can be used repeatedly.
Furthermore, in showcases, show windows and windows, the surfaces are routinely cleaned, and by satisfying condition 3, it becomes possible to maintain the property of reducing the adhesive strength of the adherend even through repeated cleaning. Therefore, by satisfying condition 3, it is preferable in that the configuration in which the release laminate of the present invention is applied to the surfaces of showcases, show windows and windows can be made more useful.
In this specification, the term "showcase" refers to a box whose interior can be seen in a normal state, and is a concept that includes refrigerators and freezers.

In order to make it easier to satisfy condition 3, it is preferable to increase the scratch resistance of the surface of the release laminate (the surface of the release layer).
Specifically, it is preferable to dispose a layer containing an inorganic compound between the transparent plastic film and the release layer. It is also preferable that the layer containing an inorganic compound further contains a binder resin. Furthermore, it is preferable to subject the surface of the layer containing an inorganic compound to a treatment described below.

It is preferable that the release laminate of the present invention further satisfies the following condition 4.
<Condition 4>
The surface of the release layer of the release laminate is rubbed back and forth 5000 times with a cotton 300 number flannel cloth at a load of 500 g/ ^cm2 to obtain the friction laminate 2. The adhesive tape A is attached to the surface of the release layer side of the friction laminate 2. Water is dropped with a dropper so that at least the area where the adhesive tape A is attached and the area 1 cm outside the outer edge of the adhesive tape A are covered with water on the surface of the release layer side of the friction laminate 2. Five minutes after the water dropping is completed, when the adhesive tape A is peeled off in accordance with Method 1 of JIS Z0237:2009 except that the test plate is not stainless steel but the friction laminate 2, the peel strength is P4 (N/10 mm), and P4/PA is 0.2 or less.

<Transparent plastic film>
The transparent plastic film can be formed from a resin such as polyester, triacetyl cellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl polymethacrylate, polycarbonate, polyurethane, and amorphous olefin (Cyclo-Olefin-Polymer: COP).
Among these transparent plastic films, from the viewpoint of mechanical strength and dimensional stability, stretched polyester films, particularly biaxially stretched polyester films, are preferred. Among polyester films, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferred.

The thickness of the transparent plastic film is preferably from 5 to 500 μm, and more preferably from 10 to 200 μm.
Furthermore, the transparent plastic film preferably has a total light transmittance according to JIS K7361-1:1997 of 80% or more, more preferably 90% or more, and even more preferably 95% or more.

In order to improve adhesion with a layer to be formed on the transparent plastic film, one or both sides of the transparent plastic film may be subjected to an easy-adhesion treatment, such as a physical or chemical surface treatment, such as an oxidation method or a roughening method. From the same viewpoint, it is also preferable to form an easy-adhesion layer on the transparent plastic film.

<Layer Containing Inorganic Compound>
It is preferable that the release laminate has a layer containing an inorganic compound between the transparent plastic film and the release layer. By adopting such a configuration, the adhesion between the transparent plastic film and the release layer becomes good, and conditions 1 to 4 can be easily satisfied.

The layers containing an inorganic compound can be roughly divided into those formed by a wet method and those formed by a dry method.
Examples of the wet method include a method of forming the layer by a sol-gel method using a metal alkoxide or the like, and a method of forming the layer by applying a coating liquid in which inorganic particles are contained in a binder resin composition.
Dry methods include physical vapor deposition and chemical vapor deposition using inorganic particles as a raw material.
The wet method is excellent in terms of production efficiency. In addition, the layer containing an inorganic compound formed by the wet method is preferable in terms of excellent coating suitability of the release layer. Furthermore, the layer containing an inorganic compound formed by the wet method is preferable in terms of easy to improve adhesion with the layer directly below (e.g., transparent plastic film, hard coat layer).
Among the wet methods, a method of applying and drying a coating liquid containing inorganic particles as an inorganic compound and a binder resin composition is preferred. That is, the layer containing an inorganic compound preferably contains inorganic particles as an inorganic compound and a binder resin.

The particle size of the inorganic particles is not particularly limited, but from the standpoint of transparency and suppression of particle shedding, the average primary particle size is preferably 5 to 200 nm, and more preferably 10 to 150 nm.

The average primary particle size of the inorganic particles can be calculated by the following steps (1) to (3).
(1) The cross section of the release laminate is photographed by a TEM or STEM. The acceleration voltage of the TEM or STEM is preferably 10 kV to 30 kV, and the magnification is preferably 50,000 to 300,000.
(2) Randomly extracting 10 primary particles from the observed image, and calculating the particle diameter of each primary particle. The particle diameter is measured as the distance between two parallel lines that is the maximum distance between the cross section of the primary particle.
(3) The same procedure is repeated five times on a separate observation image of the same sample, and the value obtained from the number average of a total of 50 particles is regarded as the average particle size of the primary particles.

Examples of inorganic particles include silica, magnesium fluoride, alumina, zirconia, and titania. Among these, from the viewpoint of reducing reflectance, low refractive index inorganic particles such as silica and magnesium fluoride are preferred. When the reflectance is reduced, it can be suitably used in applications where visibility is important, such as showcases, show windows, and windows.
In addition, the low refractive index inorganic particles are preferably those having voids from the viewpoint of reducing reflectance. The inorganic particles having voids have fine voids inside and contain air in the voids, so that they have a low refractive index. The inorganic particles having voids include porous inorganic particles and hollow inorganic particles, and among them, hollow inorganic particles are preferred. Among the hollow inorganic particles, hollow silica is preferred.

The hollow inorganic particles refer to particles that have an outer shell layer made of an inorganic compound, and the inside of the particle surrounded by the outer shell layer is hollow, containing air inside the particle.
The shape of the hollow inorganic particles may be any of a spherical shape, a spheroidal shape, a nearly spherical shape such as a polyhedral shape that can approximate a sphere, a chain shape, a needle shape, a plate shape, a flake shape, a rod shape, a fiber shape, etc. Among them, a spherical shape or a nearly spherical shape is preferable, and a spheroidal shape or a spherical shape is more preferable.

Hollow inorganic particles can reduce the refractive index, but tend to have poorer water resistance and scratch resistance than other low refractive index inorganic particles. In particular, when hollow particles having a large particle size and a high air ratio are used, the water resistance and scratch resistance of the layer containing an inorganic compound are likely to be reduced.
However, in the release laminate of the present invention, even when the layer containing an inorganic compound contains hollow inorganic particles, the release layer located on the layer containing an inorganic compound can compensate for the weak points of the hollow inorganic particles (reduction in water resistance and scratch resistance).Furthermore, when the layer containing an inorganic compound contains hollow inorganic particles, the surface of the layer containing an inorganic compound is treated as described below, which improves the adhesion between the layer containing an inorganic compound and the release layer, and is preferable in that the weak points of the hollow inorganic particles (reduction in water resistance and scratch resistance) can be further compensated for.

The low refractive index inorganic particles may be surface-treated, but from the viewpoint of improving adhesion between the layer containing the inorganic compound and the release layer, it is preferable that the surface is untreated.

The content of the inorganic particles is preferably from 20 to 250 parts by mass, more preferably from 30 to 230 parts by mass, and even more preferably from 40 to 200 parts by mass, per 100 parts by mass of the binder resin in the layer containing an inorganic compound.
By making the content of the inorganic particles 20 parts by mass or more, it is possible to easily improve the adhesion between the layer containing the inorganic compound and the release layer. In addition, when the inorganic particles are low refractive index inorganic particles, by making the content of the inorganic particles 20 parts by mass or more, it is possible to improve the antireflection properties.
Furthermore, by setting the content of inorganic particles to 250 parts by mass or less, it is possible to suppress a decrease in the coating strength of the layer containing an inorganic compound, and in turn to easily suppress a decrease in the scratch resistance of the release laminate.
In addition, the low refractive index inorganic particles may be used in combination with hollow inorganic particles and other low refractive index inorganic particles. In this case, the ratio of the hollow inorganic particles to the total amount of the low refractive index inorganic particles is preferably 50% by mass or more, more preferably 60% by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

The binder resin of the layer containing an inorganic compound preferably contains a cured product of a curable resin composition such as a thermosetting resin composition or an ionizing radiation curable resin composition, and from the viewpoint of improving scratch resistance, it is more preferable to contain a cured product of an ionizing radiation curable resin composition.

It is preferred that the binder resin of the layer containing an inorganic compound does not substantially contain a fluorine component, from the viewpoints of adhesion to the release layer and the coatability of a coating solution for the release layer.
"Substantially free" means that the content of fluorine components, calculated as fluorine atoms, relative to the total amount of the binder resin in the layer containing an inorganic compound is 1 mass% or less, preferably 0.1 mass% or less, more preferably 0.01 mass% or less, and even more preferably 0 mass%.

The thermosetting resin composition is a composition that contains at least a thermosetting resin, and is a resin composition that is cured by heating.
Examples of the thermosetting resin include acrylic resin, urethane resin, phenol resin, urea melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, etc. In the thermosetting resin composition, a curing agent is added to the curable resin as required.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl group, vinyl group, and allyl group, as well as epoxy group, oxetanyl group, and the like. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferred, a compound having two or more ethylenically unsaturated bond groups is more preferred, and among them, a polyfunctional (meth)acrylate-based compound having two or more ethylenically unsaturated bond groups is even more preferred. As the polyfunctional (meth)acrylate-based compound, either a monomer or an oligomer can be used.
The ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Usually, ultraviolet rays (UV) or electron beams (EB) are used, but other types of radiation such as electromagnetic waves, such as X-rays and gamma rays, and charged particle beams, such as alpha rays and ion beams, can also be used.
In this specification, (meth)acrylate means acrylate or methacrylate, (meth)acrylic acid means acrylic acid or methacrylic acid, and (meth)acryloyl group means acryloyl group or methacryloyl group.

Among the polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate.
Examples of trifunctional or higher (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.
The (meth)acrylate monomer may have a part of its molecular skeleton modified, and may be modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, an alkyl, a cyclic alkyl, an aromatic, a bisphenol, or the like.

Examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.
The urethane (meth)acrylate can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate.
In addition, preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting a tri- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with (meth)acrylic acid, (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a polybasic acid and (meth)acrylic acid, and (meth)acrylates obtained by reacting a di- or higher functional aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a phenol and (meth)acrylic acid.
The above ionizing radiation curable compounds may be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet ray curable compound, the ionizing radiation curable composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator.
The photopolymerization initiator may be one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl dimethyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, and the like.
The photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and increase the curing speed, and examples of the accelerator include one or more types selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, and the like.

When the layer containing an inorganic compound contains inorganic particles as the inorganic compound and a binder resin, it is preferable that the inorganic particles are exposed on at least a part of the surface of the layer containing an inorganic compound (the surface of the layer containing an inorganic compound on the release layer side). By exposing the inorganic particles from the surface of the layer containing an inorganic compound, it is possible to easily improve the adhesion between the layer containing an inorganic compound and the release layer.
In order to expose the inorganic particles from the surface of the layer containing an inorganic compound, it is preferable to subject the surface of the layer containing an inorganic compound to a corona discharge treatment or a saponification treatment after the formation of the layer containing an inorganic compound. When the layer containing inorganic particles and a binder resin is formed, the surface of the inorganic particles is covered with the binder resin. Here, the thickness of the binder resin covering the surface of the inorganic particles is thick in some places and thin in others. Then, the thin skin of the binder resin is removed from the part of the surface of the inorganic particles that is thinly covered with the binder resin by the corona discharge treatment or saponification treatment described above, and the inorganic particles are exposed.

The layer containing an inorganic compound preferably contains a silane coupling agent from the viewpoints of further improving the adhesion to the release layer and maintaining the releasability of the bonded material by dropping water for a longer period of time.
Examples of the silane coupling agent include alkoxysilanes such as tetraethoxysilane and methyltriethoxysilane, vinyl-based silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, silane coupling agents containing a (meth)acryloyl group such as 3-methacryloxypropyltriemethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-acryloxypropyltriethoxysilane, epoxy-based silane coupling agents, amino-based silane coupling agents, etc. Among these, silane coupling agents containing a (meth)acryloyl group are preferred from the viewpoint of scratch resistance.

The content of the silane coupling agent is preferably 5 to 60 mass %, more preferably 7 to 45 mass %, and even more preferably 10 to 30 mass %, of the total solid content of the layer containing the inorganic compound.

The thickness of the layer containing an inorganic compound is not particularly limited, but when low refractive index particles are used as the inorganic compound, from the viewpoint of suppressing reflectance, the thickness is preferably 70 to 120 nm, more preferably 80 to 110 nm, and even more preferably 85 to 105 nm.
The thickness of the layer containing an inorganic compound can be calculated, for example, by measuring the thickness at 20 points on a cross-sectional image taken with a scanning transmission electron microscope (STEM) and averaging the values at the 20 points. The thicknesses of the release layer, hard coat layer, and high refractive index layer described later can be calculated in the same manner.

When low refractive index particles are used as the inorganic compound, the refractive index of the layer containing the inorganic compound (low refractive index layer) is preferably 1.26 to 1.37, more preferably 1.28 to 1.35, and even more preferably 1.30 to 1.33.
In this specification, the refractive index can be calculated, for example, by fitting a reflection spectrum measured by a reflectance photometer to a reflection spectrum calculated from an optical model of a multilayer thin film using Fresnel coefficients.

<Release layer>
The release layer is formed on the outermost surface of the release laminate.
The release layer must not swell or dissolve when water is dropped onto it under conditions 2 to 4.

The release layer is preferably a cured product of a release layer-forming composition containing a silica sol dispersed in an organic solvent.
The organic solvent-dispersed silica sol is a colloidal solution in which colloidal silica with a particle size of nano-order is dispersed in an organic solvent. A release layer-forming composition containing an organic solvent-dispersed silica sol is applied, and the silica sol is dehydrated and condensed by heating or the like, to obtain a cured product of the release layer-forming composition containing an organic solvent-dispersed silica sol. Examples of the organic solvent of the organic solvent-dispersed silica sol include alcohol, glycol, ester, ketone, ether, saturated hydrocarbon, and unsaturated hydrocarbon.
The particle size of the silica sol is preferably 1 to 20 nm, from the viewpoint of setting the thickness of the release layer within the range described below.

Specific examples of organic solvent-dispersed silica sols include Nissan Chemical Industries' products under the trade names IPA-ST (particle diameter: about 12 nm), IPA-ST-UP (particle diameter: about 9-15 nm), MIBK-ST (particle diameter: about 12 nm), PMA-ST (particle diameter: about 12 nm), PGM-ST (particle diameter: about 12 nm), and MIBK-SD (particle diameter: about 12 nm); Fuso Chemical Industries' products under the trade names PL-1-IPA (10-15 nm), PL-1-TOL (10-15 nm), PL-1-PGME (10-15 nm), and PL-1-MEK (10-15 nm); and JGC Catalysts and Chemicals' product under the trade name Sururia.

The release layer is preferably a cured product of a release layer-forming composition containing a modified organic solvent-dispersed silica sol. The modified organic solvent-dispersed silica sol is prepared by reacting silanol of silica sol with a silane coupling agent represented by the following formula (I).
The cured product of the composition containing the modified product (produced by reacting the silanol of silica sol with a silane coupling agent represented by the following formula (I)) has a high level of hydrophilicity, while having adhesiveness to the adhesive tape due to the presence of an organic group, so that condition 1 can be easily satisfied. In addition, the cured product of the composition containing the modified product has a high level of hydrophilicity, and water penetrates between the adhesive tape attached to the release layer and the surface of the release layer, weakening the adhesive strength of the adhesive tape, making it easier to satisfy condition 2. In addition, the cured product of the composition containing the modified product has excellent adhesion to a layer containing an inorganic compound, and can improve the scratch resistance of the release laminate, making it easier to satisfy condition 3. Furthermore, the cured product of the composition containing the modified product has a low refractive index of about 1.4, making it easier to reduce the reflectance.
The above-mentioned action is considered to be caused by "having minute hydrophilic and hydrophobic domains on the surface of the cured product of the composition containing the modified substance" and "establishing the relationship that the coordination energy of water to the hydrophilic domain is greater than the bonding strength between the hydrophobic domain and the pen component." In addition, the reason why the release layer does not peel off when water is dropped is considered to be because the modified substance is chemically bonded to the inorganic compound in the layer containing the inorganic compound.

(W) _3-k (R) _k Si-R ¹ -(X-R ² ) _m -N ⁺ (R ³ )(R ⁴ )-R ⁵ -Y (I)
[In formula (I), W represents an alkoxy group having 1 to 3 carbon atoms, R represents an alkyl group having 1 to 3 carbon atoms, k represents 0 or 1, ^R1 represents an alkylene group having 1 to 5 carbon atoms, X represents -NHCOO-, -NHCONH- or -S-, m represents 0 or 1, ^R2 represents an alkylene group having 1 to 10 carbon atoms which may contain an ether bond, an _ester bond ^or an amide bond or _-CH2CH2N ⁺ ( _CH3 ){( _CH2 ) _nY )} _{CH2CH2OCH2CH2-} , _R3 ^and _R4 represent alkyl groups having 1 to 3 carbon atoms _which may be the same or different, ^R5 represents a methylene group, an ethylene group, a propylene group or a methylenephenylene group, and ^Y represents ^-COO- or _-SO3- .]

Examples of R (an alkyl group having 1 to 3 carbon atoms) in the above formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and the like, with the methyl group being preferred among these.
Examples of R ¹ (alkylene group having 1 to 5 carbon atoms) in the above formula (I) include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group, and among these, a trimethylene group is preferred.
As R ² in the above formula (I), an ethylene group, a trimethylene group, an ethyleneoxyethylene group, and --CH ₂ CH ₂ N ⁺ (CH ₃ ){(CH ₂ ) _n Y)}CH ₂ CH ₂ OCH ₂ CH ₂ -- are preferred.
Examples of the alkyl group having 1 to 3 carbon atoms for R ³ and R ⁴ in the above formula (I) include a methyl group, an ethyl group, etc., and among these, a methyl group is preferred.

Specific examples of the silane coupling agent of the above formula (I) include the following compounds.
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ OCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ N ⁺ (CH ₃ ) (CH ₂ COO ^- ) CH ₂ CH ₂ OCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCONHCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCONHCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ COOCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ^-
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ COO ^-
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ C ₆ H ₄ COO ^-
(C ₂ H ₅ O) ₂ Si(CH ₃ )CH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ COO ⁻
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CCH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ OCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCOOCH ₂ CH ₂ N ⁺ (CH ₃ ) (SO ₃ ⁻ ) CH ₂ CH ₂ OCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ^-
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCONHCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCONHCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ COOCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻
(C ₂ H ₅ O) ₂ Si(CH ₃ )CH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ ⁻

The silane coupling agent of formula (I) can be obtained by reacting a dialkylamino group-containing silicon compound (e.g., a dimethylamino group-containing silicon compound) with a haloacetic acid compound, a sultone ring compound, or a lactone ring compound.

The temperature at which the silane coupling agent of formula (I) is added is not limited, but is preferably between about 20° C. and the boiling point of the solvent.
The reaction temperature is not limited, but is preferably between about 20° C. and the boiling point of the solvent.
The reaction time is not limited, but is preferably from 10 minutes to 48 hours, and more preferably from 6 hours to 24 hours.

Solvents used in the reaction to obtain the silane coupling agent of formula (I) include ester solvents such as methyl acetate, ethyl acetate, and butyl acetate, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, tert-butanol, pentanol, ethylene glycol, propylene glycol, propylene glycol monomethyl ether, and 1,4-butanediol, ether solvents such as diethyl ether, tetrahydrofuran, and dioxane, ketone solvents such as acetone and methyl ethyl ketone, aprotic solvents such as dimethyl sulfoxide and N,N-dimethylformamide, aromatic hydrocarbon solvents such as toluene and xylene, and mixed solvents thereof.

The reaction temperature in obtaining the silane coupling agent of formula (I) is preferably the boiling point of the solvent used or higher, and the reaction may be carried out under pressure in order to maintain the temperature at or above the boiling point.
The reaction time is usually from 6 to 36 hours, preferably from 8 to 36 hours, and more preferably from 8 to 24 hours.

As the dimethylamino group-containing silicon compound which is the raw material of the silane coupling agent of the formula (I), a commercially available product can be used as it is.
Alternatively, a compound having an -NHCOO- group can be obtained by reacting a commercially available dimethylamino group-containing alcohol (for example, 2-dimethylaminoethanol, 3-dimethylaminopropanol, 4-dimethylaminobutanol, 2-dimethylaminoethoxyethanol, and N,N,N'-trimethyl-N'-(2-hydroxyethyl)-bis(2-aminoethyl ether) with a silane coupling agent having an isocyanate group (for example, 3-isocyanatepropyltriethoxysilane), or a commercially available dimethylamino group-containing amine (for example, N,N-dimethylethylenediamine, N,N-dimethyl-1,3-propanediamine) with a silane coupling agent having an isocyanate group (for example, 3-isocyanatepropyltriethoxysilane), and a compound having an -NHCONH- group can be obtained and used.
In addition, a thioether group-containing silicon compound can be obtained by reacting dimethylallylamine, 2-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl methacrylate, N-[3-(dimethylamino)propyl]acrylamide, N-[3-(dimethylamino)propyl]methacrylamide, or the like with a thiol group-containing silicon compound (e.g., 3-mercaptopropyltrimethoxy, 3-mercaptopropylmethyldimethoxysilane, or the like) and used.

Examples of the solvent used when reacting the silanol of the silica sol with the silane coupling agent of formula (I) include alcohol solvents: methanol, ethanol, isopropanol, n-butanol, t-butanol, pentanol, ethylene glycol, propylene glycol, 1,4-butanediol, and the like; ether solvents: diethyl ether, tetrahydrofuran, dioxane, and the like; ketone solvents: acetone, methyl ethyl ketone, and the like; aprotic solvents: dimethyl sulfoxide, N,N-dimethylformamide, and the like; water and mixed solvents thereof.
Of these, alcohol-based solvents and water are preferred, and these solvents can be used alone or in combination of two or more.

The amount of raw silica sol per 100 parts by weight of solvent is preferably 1 to 50 parts by weight, and more preferably 1 to 30 parts by weight.

The amount of the silane coupling agent of formula (I) relative to the silica sol is preferably 0.1 to 10.0 mmol, more preferably 0.5 to 5.5 mmol, relative to 1 g of silica sol.
By setting the amount to 0.1 mmol or more, the hydrophilicity of the cured product can be easily improved, and by setting the amount to 10.0 mmol or less, self-condensation between the silane coupling agents can be suppressed, and the hardness of the cured product can be prevented from being insufficient due to a lack of silanol groups in the silica sol, resulting in a decrease in the scratch resistance of the release layer.

The modified silica sol dispersed in an organic solvent (obtained by reacting the silanol of the silica sol with the silane coupling agent of formula (I)) is modified with a functional group shown in formula (II) below.
(-O-) _3-k (R) _k Si-R ¹ -(X-R ² ) _m -N ⁺ (R ³ )(R ⁴ )-R ⁵ -Y (II)
The embodiments of each symbol (k, R, Y, etc.) in formula (II) are the same as the embodiments of each symbol in formula (I) above.

Further, examples of modified organic solvent-dispersed silica sol include those obtained by reacting silanol of silica sol with a silane coupling agent containing a (meth)acryloyl group.
Examples of such silane coupling agents containing a (meth)acryloyl group include 3-methacryloxypropyltriemethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltriethoxysilane.

The release layer-forming composition containing the modified organic solvent-dispersed silica sol may further contain other curable components such as a normal organic solvent-dispersed silica sol and a curable resin composition.
The curable resin composition contained in the release layer-forming composition can be the same as the curable resin composition exemplified in the layer containing an inorganic compound. By including the curable resin composition in the release layer-forming composition, the adhesion with the layer containing an inorganic compound can be further improved.
The content of the curable resin composition is preferably 5 to 30 parts by mass per 100 parts by mass of the active ingredient of the silica sol, from the viewpoint of the balance between the hydrophilicity of the release layer and the adhesion to the layer containing an inorganic compound.

The release layer forming composition can be applied to a plastic film or a layer containing an inorganic compound, dried, and then cured by dehydration condensation of the silica sol. The dehydration condensation of the silica sol can also proceed by heat treatment, but it is preferable to use a catalyst such as a base or an acid to promote the dehydration condensation. The catalyst may be added to the release layer forming composition, or the release layer may be exposed to a catalytic atmosphere after the release layer is formed.
The temperature conditions for the dehydration condensation of the silica sol are not particularly limited, and may be appropriately determined within the range of 20 to 250°C.
In addition, when the release layer-forming composition contains a curable resin composition, curing of the silica sol and curing of the curable resin composition may be carried out simultaneously, or one of them may be carried out first.

The thickness of the release layer is preferably from 1 to 25 nm, more preferably from 3 to 20 nm, and even more preferably from 5 to 15 nm.
By making the thickness of the release layer 1 nm or more, the scratch resistance of the release layer can be easily improved. Also, by making the thickness of the release layer 25 nm or less, the deterioration of anti-reflection performance can be suppressed. Furthermore, by making the thickness of the release layer 25 nm or less, the molecules constituting the release layer are arranged in an orderly manner, and the release layer has a high degree of hydrophilicity, which is thought to make it easier to satisfy condition 2.

The refractive index of the release layer is preferably 1.49 or less, and more preferably 1.46 or less. By making the refractive index of the release layer 1.49 or less, it is possible to further suppress the deterioration of the antireflection performance when the refractive index of the layer containing an inorganic compound is reduced.
The lower limit of the refractive index of the release layer is about 1.30.

<Hard Coat Layer>
It is preferable to have a hard coat layer between the transparent plastic film and the release layer in order to improve scratch resistance. When a layer containing an inorganic compound is present between the transparent plastic film and the release layer, it is preferable to have a hard coat layer between the transparent plastic film and the layer containing an inorganic compound.

The hard coat layer preferably contains a cured product of a curable resin composition such as a thermosetting resin composition or an ionizing radiation curable resin composition, and from the viewpoint of improving scratch resistance, it more preferably contains a cured product of an ionizing radiation curable resin composition.
The heat-curable resin composition and ionizing radiation-curable resin composition for the hard coat layer may be the same as the heat-curable resin composition and ionizing radiation-curable resin composition for the layer containing an inorganic compound described above.

The thickness of the hard coat layer is preferably 0.1 to 100 μm, more preferably 0.5 to 20 μm, and even more preferably 1 to 10 μm. By setting the thickness of the hard coat layer within the above range, it is possible to improve scratch resistance while making it easier to suppress curling.

The refractive index of the hard coat layer is preferably adjusted in the range of 1.45 to 1.70. In addition, when the layer containing an inorganic compound is made to have a low refractive index, and a high refractive index layer is in contact with the transparent plastic film side of the layer containing the inorganic compound with a low refractive index, the refractive index of the hard coat layer is preferably lower than that of the high refractive index layer, more preferably 1.50 to 1.65, and even more preferably 1.55 to 1.60. If the refractive index of the hard coat layer is in this range, the hard coat layer acts as a medium refractive index layer, and interference action is possible between the three layers of the hard coat layer (medium refractive index layer), the high refractive index layer, and the low refractive index layer (layer containing an inorganic compound with a low refractive index), so the reflectance can be reduced.

As a means for imparting the role of a medium refractive index layer to the hard coat layer, there are a means for blending a resin having a high refractive index into the hard coat layer coating liquid and a means for blending particles having a high refractive index.
Examples of the resin having a high refractive index include the above-mentioned thermosetting resin or ionizing radiation curable compound into which a group containing sulfur, phosphorus, or bromine, an aromatic ring, etc. are introduced. Examples of the particles having a high refractive index include the same particles as those used in the high refractive index layer described later.

<High refractive index layer>
When the layer containing an inorganic compound has a low refractive index, from the viewpoint of further reducing the reflectance of the release laminate, it is preferable to have a high refractive index layer in contact with the transparent plastic film side of the layer containing the inorganic compound with a low refractive index.
The high refractive index layer can be formed, for example, from a high refractive index layer coating liquid containing high refractive index particles and a binder resin composition.

Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.
The average particle size of the primary particles of the high refractive index particles is preferably from 3 to 200 nm, more preferably from 5 to 100 nm, and even more preferably from 7 to 50 nm.

From the viewpoint of achieving a balance between the high refractive index of the coating film and the strength of the coating film, the content of the high refractive index particles is preferably 50 to 1,000 parts by mass, more preferably 100 to 750 parts by mass, and even more preferably 200 to 500 parts by mass, per 100 parts by mass of the binder resin.

The binder resin for the high refractive index layer may be a cured product of a curable resin composition. As the curable resin composition, the same ones as those exemplified for the layer containing an inorganic compound may be used, and an ionizing radiation curable resin composition is preferable.

The refractive index of the high refractive index layer is preferably from 1.55 to 1.85, and more preferably from 1.56 to 1.75.
The thickness of the high refractive index layer is preferably 200 nm or less, and more preferably 50 to 180 nm.

<Other demographics>
The release laminate of the present invention may have other layers.
For example, the transparent plastic film may have an adhesive layer, an antistatic layer, a printed layer, etc. on the surface opposite to the layer containing an inorganic compound.

<Other physical properties>
When the release laminate is used in a showcase, a show window, a window, or the like, from the viewpoint of improving visibility, the haze according to JIS K7136:2000 is preferably less than 2.0%, more preferably 1.5% or less, and even more preferably 1.0% or less.
In addition, the term "light-transmitting areas" is intended to exclude areas where light transmittance has been reduced (areas where the total light transmittance is 50% or less), for example, due to the formation of a printed layer on the side of the transparent plastic film opposite the layer containing an inorganic compound.

The surface of the release layer side of the release laminate preferably has an arithmetic mean roughness Ra (JIS B0601:1994) of 0.02 μm or less with a cutoff value of 0.08 mm, and more preferably 0.01 μm or less.

The reflectance of the surface of the release layer side of the release laminate is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. By lowering the reflectance, visibility is improved, making it suitable for use in showcases, show windows, windows, etc.

In this specification, the reflectance refers to the luminous reflectance Y value of the CIE 1931 standard color system, and is the average value of measurements at 10 points.
In this specification, the reflectance of the surface on the release layer side of the release laminate is measured by preparing a sample by bonding a black plate to the opposite side of the release laminate from the surface on which the reflectance is to be measured via a transparent adhesive layer, and illuminating the release layer side of the sample with light at an incident angle of 5°. The light source used for measuring the reflectance is preferably D65.
The refractive index difference between the transparent adhesive layer and a member (e.g., a transparent plastic film) in contact with the sample's transparent adhesive layer is preferably within 0.15, more preferably within 0.10. The black plate preferably has a total light transmittance of 1% or less, more preferably 0%, according to JIS K7361-1:1997. The refractive index difference between the resin constituting the black plate and the transparent adhesive layer is preferably within 0.15, more preferably within 0.10.

<Size, shape, etc.>
The release laminate may be in the form of a sheet or a roll.
The size of the sheet is not particularly limited, but is generally about 2 to 500 inches diagonally. The width and length of the roll are not particularly limited, but generally, the width is about 500 to 3000 mm, and the length is about 500 to 5000 m.
The shape of the sheets is not particularly limited either, and may be, for example, polygonal (triangle, square, pentagon, etc.) or circular, or may be a random, indeterminate shape.

<Application>
The above-mentioned release laminate of the present invention can be used, for example, as a release substrate for a transfer sheet and a process sheet, and can also be used as a surface member for a showcase, a show window, and a window.

[Transfer sheet]
The transfer sheet of the present invention comprises a transfer layer on the release layer of the above-mentioned release laminate of the present invention.
That is, the transfer sheet of the present invention uses the above-mentioned releasable laminate as a releasable substrate of the transfer sheet.

The transfer sheet of the present invention allows the release layer to be sufficiently adhered to the release laminate (releasable substrate) before the initial transfer, and after the transfer layer is adhered to the adherend, the release laminate (releasable substrate) can be easily peeled off from the transfer layer by the simple process of dripping water.

The transfer layer of the transfer sheet may, for example, have a functional layer and an adhesive layer. In this configuration, the functional layer is disposed on the side of the releasable laminate (releasable substrate). Examples of the functional layer include a hard coat layer, an anti-reflection layer, and an anti-fouling layer.

[Process sheet]
The process sheet of the present invention has, on its outermost surface, the release layer of the release laminate of the present invention described above.

The process sheet of the present invention adheres electronic components and the like with sufficient adhesive strength via the adhesive, and after the process is completed, the processed electronic components and the like can be easily peeled off from the process sheet by the simple process of dripping water on them.

[Goods]
The article of the present invention is obtained by disposing the release layer of the above-mentioned release laminate of the present invention so that it faces the front surface.

The article includes a showcase, a show window, and a window. That is, the article of the present invention includes a showcase, a show window, and a window in which the release layer of the release laminate is arranged so as to face the surface.
The article of the present invention allows displays such as advertisements to be fixed with sufficient adhesive strength using the adhesive tape, and when the display needs to be changed, the display can be easily peeled off by the simple process of dropping water on it.

The present invention will be specifically described below with reference to examples and comparative examples. Note that the present invention is not limited to the embodiments described in the examples.

The release laminates obtained in the Examples and Comparative Examples were subjected to the following measurements and evaluations. The results are shown in Table 1.

1-1. Check conditions 1 to 3 (1)
An adhesive tape A1 having a peel strength of 3N/10mm according to method 1 (180° peeling from a stainless steel test plate) of JIS Z0237:2009 was prepared, and the peel strengths P1 (N/10mm), P2 (N/10mm), and P3 (N/10mm) under conditions 1 to 3 were measured to confirm whether conditions 1 to 3 were met. Those that met each condition were rated as "A," and those that did not were rated as "C." A Tensilon universal testing machine manufactured by Orientec Co., Ltd. was used to measure the peel strength, and the peel speed was 300mm/min.
The atmosphere during conditions 1 to 3 was set to a temperature of 23° C.±5° C. and a humidity of 40 to 65%. Before carrying out conditions 1 to 3, each sample was left in the above atmosphere for 10 minutes or more.
In addition, under conditions 3 and 4, the reciprocating friction was performed using a Gakushin type friction tester conforming to JIS L0849:2013, at a speed of 30 mm one way and 1 second per reciprocating motion.
In conditions 2 and 3, ion-exchanged water was used as the water. In conditions 1 to 3, the width of the adhesive tape was 10 mm, and the length of the area of the adhesive tape that was attached to the release laminate was 50 mm. In conditions 2 and 3, the amount of water dropped was 20 ml.

1-2. Check conditions 1 to 3 (2)
An adhesive tape A2 having a peel strength of 7 N/10 mm according to Method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate) was prepared, and in the same manner as in 1-1 above, it was confirmed whether or not the conditions 1 to 3 were satisfied.

1-3. Steel wool resistance (SW resistance)
The release laminates of the Examples and Comparative Examples were cut to a size of 5.0 cm x 5.0 cm, and then a sample (5.0 cm x 5.0 cm) was produced by bonding a 25 μm thick transparent adhesive layer (manufactured by PANAC Corporation, product name: Panaclean PD-S1) and a 2 mm thick transparent glass plate to the transparent plastic film side.
The surface of the release layer side of the sample was pressed against #0000 steel wool, and rubbed 10 times with a load of 500 g/ ^cm2. A black plate was placed on the back of the sample, and the sample was visually evaluated under fluorescent lighting to see whether scratches were visible from the release layer side. Those with no visible scratches were rated as "A," and those with visible scratches were rated as "C." Furthermore, for those with an evaluation of A at ^a load of 500 g/cm2, those with no visible scratches were rated as "AA" when the same evaluation was performed at a load of 700 g/ ^cm2 .

1-4. Reflectance (visible reflectance Y value)
A sample (5 cm x 5 cm) was prepared by bonding a black plate (manufactured by Kuraray Co., Ltd., product name: COMOGLAS DFA2CG 502K (black) series, total light transmittance 0%, thickness 2 mm, refractive index 1.49) to the transparent plastic film side of the release laminate of the examples and comparative examples via a 25 μm thick transparent adhesive layer (manufactured by PANAC Corporation, product name: PANACLEAN PD-S1, refractive index 1.49).
When the direction perpendicular to the surface of the release laminate was defined as 0 degrees, light was incident on the sample from a direction of 5 degrees, and the reflectance of the sample (visual reflectance Y value) was measured based on the specular reflection of the incident light.
The reflectance was measured by measuring the 5° regular reflectance in the wavelength range of 380 to 780 nm using a spectral reflectance meter (Shimadzu Corporation, product name: MPC3100), and then calculating the luminous reflectance using software (built into the MPC3100) that converts the reflectance into the brightness perceived by the human eye. The reflectance was measured at 10 points for each sample, and the average value was taken as the reflectance of each sample.

2. Preparation of Coating Solution The following coating solutions were prepared.
<Coating solution for hard coat layer>
Urethane acrylate (product name "UX5005", manufactured by Nippon Kayaku Co., Ltd., 9 functional) 50 parts by mass Pentaerythritol triacrylate 25 parts by mass Acrylate monomer (product name "R684", manufactured by Nippon Kayaku Co., Ltd., 2 functional) 25 parts by mass Photopolymerization initiator (product name "Irgacure 184", manufactured by BASF Corporation) 4 parts by mass Leveling agent (product name "Megafac F477", manufactured by DIC Corporation) 0.2 parts by mass Methyl ethyl ketone 125 parts by mass Propylene glycol monomethyl ether acetate 25 parts by mass

<Coating Solution for Layer Containing Inorganic Compound (Low Refractive Index Layer)>
Propylene oxide modified pentaerythritol tetraacrylate (trade name "ATM-4P", manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100%) 75 parts by mass Pentaerythritol triacrylate 25 parts by mass Hollow silica fine particle-containing dispersion (solid content 20%, average primary particle diameter 60 nm) 800 parts by mass Reactive silica fine particle-containing dispersion (trade name "MIBK-SD", manufactured by Nissan Chemical Industries, Ltd., solid content 30%, average primary particle diameter 12 nm) 83 parts by mass Photopolymerization initiator (trade name "Irgacure 127", manufactured by BASF) 7 parts by mass Methyl isobutyl ketone 9300 parts by mass Propylene glycol monomethyl ether acetate 1100 parts by mass

<Release layer coating liquid 1>
- 5 parts by mass of a solution containing the following modified silica sol dispersed in an organic solvent (solid content: approximately 0.08% by mass)
Ion-exchanged water 45 parts by weight Isopropyl alcohol 5 parts by weight

<Solution containing modified silica sol dispersed in organic solvent>
4.39 g of 1,2-oxathiolane 2,2-dioxide (Tokyo Chemical Industry Co., Ltd.) and 7.26 g of N,N-dimethyl-3-aminopropyltrimethoxysilane (Tokyo Chemical Industry Co., Ltd.) were dissolved in 40 ml of dehydrated ethyl acetate and stirred at room temperature for 24 hours. The resulting white precipitate was filtered to obtain 8.5 g of N-propyltrimethoxysilane-N,N-dimethyl-N-(3-sulfopropyl)ammonium betaine.
Next, 4.0 g of N-propyltrimethoxysilane-N,N-dimethyl-N-(3-sulfopropyl)ammonium betaine and 13.2 g of organic solvent-dispersed silica sol (Nissan Chemical Industries, IPA-ST (solid content 30%)) were dissolved in a solvent (a mixed solvent of 80 ml of ethanol and 140 ml of water) and heated under reflux overnight. After cooling, 520 mg of lithium hydroxide monohydrate (Nacalai Tesque) was dissolved in a small amount of water and added to the reaction solution for neutralization. Water was added to the resulting reaction solution to adjust it to 500 g, thereby obtaining 500 g of a solution containing a modified organic solvent-dispersed silica sol modified with (-O-) ₃ SiCH ₂ CH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ SO ₃ - groups (solid content about 1.6% by mass).

<Release layer coating liquid 2>
- 4 parts by mass of a solution containing the modified silica sol dispersed in an organic solvent (solid content: approximately 0.064 parts by mass)
_Si5O4 ( _OC2H5 ) ₁₂ (product _name "Ethyl Silicate 40", manufactured by Colcoat Co. _, Ltd.) 0.02 parts by mass (solid content equivalent)
0.002 parts by weight of 3-methacryloxypropyltrimethoxysilane 45 parts by weight of ion-exchanged water 5 parts by weight of isopropyl alcohol

3. Preparation of a release laminate [Example 1]
The coating solution for hard coat layer having the above-mentioned formulation was applied onto a 100 μm-thick polyethylene terephthalate film (refractive index 1.65), dried (70° C., 1 min), and irradiated with ultraviolet light (100 mJ/cm ² ) to form a hard coat layer having a thickness of 10 μm. Next, the coating solution for inorganic compound-containing layer (low refractive index layer) having the above-mentioned formulation was applied onto the hard coat layer, dried (90° C., 1 min), and irradiated with ultraviolet light (200 mJ/cm ² ) to form an inorganic compound-containing layer having a thickness of 90 nm and a refractive index of 1.35.
Next, the surface of the layer containing the inorganic compound was subjected to a corona discharge treatment, and then the coating solution 1 for the release layer having the above-mentioned formulation was applied, dried (100° C., 1 minute), and further heat-treated at 110° C. for 15 minutes to harden (dehydrate and condense) the silica sol, forming a release layer, thereby obtaining the release laminate of Example 1. The theoretical thickness of the release layer based on the amount of application was 10 nm.
The release layer coating solution 1 was applied to a thickness that allowed the refractive index to be measured, and the refractive index was measured to be 1.43.

[Example 2]
A release laminate of Example 2 was obtained in the same manner as in Example 1, except that the thickness of the release layer was changed to 15 nm.

[Example 3]
A release laminate of Example 3 was obtained in the same manner as in Example 1, except that the thickness of the release layer was changed to 7 nm.

[Example 4]
A release laminate of Example 4 was obtained in the same manner as in Example 1, except that the coating liquid for the layer containing an inorganic compound (low refractive index layer) was changed from "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 60 nm)" to "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 75 nm)."

[Example 5]
A release laminate of Example 5 was obtained in the same manner as in Example 1, except that the coating liquid for the layer containing an inorganic compound (low refractive index layer) was changed from "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 60 nm)" to "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 50 nm)."

[Example 6]
A release laminate of Example 6 was obtained in the same manner as in Example 1, except that the coating liquid for the layer containing an inorganic compound (low refractive index layer) was changed from "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 60 nm)" to "a dispersion containing hollow silica microparticles (solid content 20%, average primary particle diameter 100 nm)."

[Example 7]
A release laminate of Example 7 was obtained in the same manner as in Example 1, except that a high refractive index layer (refractive index 1.65, thickness 165 nm) was formed between the hard coat layer and the layer containing an inorganic compound.
The high refractive index layer was formed by applying the following coating solution for high refractive index layer, drying (90° C., 1 minute), and irradiating with ultraviolet light (200 mJ/cm ² ).
<Coating solution for high refractive index layer>
Pentaerythritol triacrylate (trade name PET30, manufactured by Nippon Kayaku Co., Ltd., solid content 100%) 100 parts by mass Antimony pentoxide-containing dispersion (trade name "V-4564", manufactured by JGC Catalysts and Chemicals Co., Ltd., solid content 40%, average primary particle size 20 nm) 1100 parts by mass Fluorine-based leveling agent (trade name "Megafac F568", manufactured by DIC Corporation, solid content 5%) 300 parts by mass Photopolymerization initiator (trade name "Irgacure 127", manufactured by BASF Corporation) 8 parts by mass

[Example 8]
The release laminate of Example 8 was obtained in the same manner as in Example 1, except that the coating liquid for the layer containing an inorganic compound (low refractive index layer) was changed to the coating liquid for the layer containing an inorganic compound (low refractive index layer) of Example 8 described below.
<Coating Solution for Layer Containing Inorganic Compound (Low Refractive Index Layer) of Example 8>
Silane coupling agent 1 (tetraethoxysilane) 25 parts by weight Silane coupling agent 2 (3-methacryloxypropyltrimethoxysilane) 25 parts by weight Pentaerythritol triacrylate 50 parts by weight Hollow silica fine particle-containing dispersion (solid content 20%, average primary particle diameter 60 nm) 800 parts by weight Photopolymerization initiator (product name "Irgacure 127", manufactured by BASF) 7 parts by weight Methyl isobutyl ketone 9300 parts by weight IPA 1100 parts by weight

[Example 9]
In the same manner as in Example 1, a hard coat layer and a layer containing an inorganic compound were formed on a polyethylene terephthalate film (refractive index: 1.65).
Next, the surface of the layer containing the inorganic compound was subjected to a corona discharge treatment, and then the coating solution 2 for the release layer having the above-mentioned formulation was applied and dried (100°C, 1 minute), and the silica sol was cured (dehydration condensation) by heat treatment at 110°C for 15 minutes, and then irradiated with ultraviolet rays (200 mJ/ ^cm2 ) to obtain a release laminate of Example 9. The theoretical thickness of the release layer based on the amount of application was 10 nm.
The release layer coating solution 2 was applied to a thickness that allowed the refractive index to be measured, and the refractive index was measured to be 1.43.

[Comparative Example 1]
A release laminate of Comparative Example 1 was obtained in the same manner as in Example 1, except that no release layer was formed on the layer containing an inorganic compound.

[Reference example 1]
A release laminate of Reference Example 1 was obtained in the same manner as in Example 1, except that a layer containing an inorganic compound was not formed on the hard coat layer, and a release layer was formed directly on the hard coat layer.

As is clear from Table 1, the release laminates of Examples 1 to 9 have a certain adhesive strength to the adhesive, while allowing the adhered material to be easily peeled off by the simple process of dropping water, and it can be confirmed that this performance can be maintained for a long period of time. Although not evaluated in the table, the release laminate of Example 8 met condition 4 in the specification and was able to maintain this performance for an extremely long period of time.

10: Transparent plastic film 20: Hard coat layer 30: Layer containing an inorganic compound 40: Release layer 100: Release laminate

Claims (9)

A release laminate having a release layer on a transparent plastic film, the release layer being located on the outermost surface of the laminate and satisfying the following conditions 1 and 2, the release layer being a cured product of a release layer-forming composition comprising an organic solvent-dispersed silica sol modified with a silane coupling agent .
<Condition 1>
Prepare an adhesive tape A having a peel strength of PA (N/10 mm) according to method 1 of JIS Z0237:2009 (180° peeling from a stainless steel test plate). When the adhesive tape A is attached to the surface of the release layer side of a release laminate and the adhesive tape A is peeled in accordance with method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength is expressed as P1 (N/10 mm), and P1/PA is 0.75 or more.
<Condition 2>
Adhesive tape A is attached to the surface of the release layer side of the release laminate. Water is dropped with a dropper so that at least the area of the surface of the release layer side of the release laminate where adhesive tape A is attached and the area 1 cm outside from the outer edge of adhesive tape A are covered with water. Five minutes after the completion of dropping water, when the adhesive tape A is peeled off in accordance with Method 1 of JIS Z0237:2009 except that the test plate is a release laminate instead of stainless steel, the peel strength P2 (N/10 mm) shows P2/PA of 0.2 or less. The release laminate according to claim 1 , further satisfying the following condition 3:
<Condition 3>
The surface of the release layer of the release laminate is rubbed back and forth 1000 times with a cotton 300 number flannel cloth at a load of 500 g/ ^cm2 to obtain the friction laminate 1. The adhesive tape A is attached to the surface of the release layer side of the friction laminate 1. Water is dropped with a dropper so that at least the area where the adhesive tape A is attached and the area 1 cm outside the outer edge of the adhesive tape A are covered with water on the surface of the release layer side of the friction laminate 1. Five minutes after the water dropping is completed, the adhesive tape A is peeled off according to JIS Z0237:2009 method 1 except that the test plate is not stainless steel but the friction laminate 1, and the peel strength is P3 (N/10 mm), and P3/PA is 0.2 or less. The release laminate according to claim 1 or 2, wherein the release layer is provided on both sides of the transparent plastic film. The release laminate according to any one of claims 1 to 3, wherein the thickness of the release layer is 1 to 25 nm. The release laminate according to any one of claims 1 to 4, having a layer containing an inorganic compound between the transparent plastic film and the release layer. The release laminate according to any one of claims 1 to 5, having a hard coat layer between the transparent plastic film and the release layer. A transfer sheet comprising a transfer layer on the release layer of the release laminate according to any one of claims 1 to 6 . A process sheet having, on its outermost surface, a release layer of the release laminate according to any one of claims 1 to 6 . An article comprising the release layer of the release laminate according to any one of claims 1 to 6 arranged so that the release layer faces the front surface.