JP7227797B2 - Machinability-enhancing film, laminate, and method of using machinability-enhancing film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a machinability-improving film, a laminate (a resin plate to which a machinability-improving film is attached), and a method of using the machinability-improving film.
In particular, the present invention relates to a machinability-improving film and laminate excellent in machinability, durability, and the like, and a method of using such a machinability-improving film, which are used when manufacturing touch panels, liquid crystal display devices, and the like.

Conventionally, there has been proposed a touch panel aimed at suppressing the generation of interference fringes due to light interference and enabling easy replacement of decorative films (see, for example, Patent Document 1).
More specifically, the touch panel has an operation area for receiving touch input and a non-operation area for not receiving touch input, and unevenness is formed on the lower surface of the decorative film corresponding to the operation area. It is a touch panel device characterized by the following.

Further, in a touch panel, a liquid crystal display device, etc., a pressure-sensitive adhesive sheet suitable for bonding a pair of uneven optical members has been proposed (see, for example, Patent Document 2).
More specifically, a base polymer (A), a monomer (B) having at least one polymerizable unsaturated group, a thermal cross-linking agent (C), a polymerization initiator (D), and a solvent (E ), and a pressure-sensitive adhesive layer (X) comprising a pressure-sensitive adhesive layer (X) obtained by semi-curing a pressure-sensitive adhesive composition containing and by heating.

Furthermore, an optical member has been proposed in which the adhesive is less likely to protrude during the punching process, less adhesion of the adhesive to the cut surface, and less likely to cause adhesive contamination or adhesive failure during handling (see, for example, Patent Document 3). ).
More specifically, it is an optical member in which the area of the adhesive that adheres to the portion other than the adhesive on the cut surface when punched is set to 20% or less of the area of the adhesive layer.

Japanese Patent Application Laid-Open No. 2018-5698 (Claims, etc.) WO2013-61938 (Claims etc.) Japanese Patent Application Laid-Open No. 2001-235626 (Claims, etc.)

However, the touch panel device disclosed in Patent Document 1 includes a predetermined exterior unit (metal sheet/adhesive layer/decorative film), and in such an exterior unit, the metal sheet and the adhesive layer are each processed into a predetermined shape. After that, it is laminated and manufactured. Therefore, it is difficult to obtain the exterior unit in that there are many manufacturing processes.
In addition, since the adhesive layer is designed so that the decorative film can be easily replaced, and no consideration is given to the adhesive strength, durability conditions (e.g., 85 ° C., 85% RH, 500 hours, etc.) ), there was also a problem that the adhesive layer was peeled off from the decorative film due to the occurrence of floating or peeling at the adhesive interface, resulting in poor durability.

In addition, the adhesive sheet disclosed in Patent Document 2 is intended only for bonding a pair of optical members having unevenness, and the adhesive sheet is sandwiched between the optical members and cut into a predetermined shape. Up until now, I hadn't considered anything.
Therefore, since the value of the gel fraction of the pressure-sensitive adhesive layer is not taken into consideration at all, the problem of poor machinability of the pressure-sensitive adhesive sheet has also been observed.

Furthermore, in the optical member disclosed in Patent Document 3, specifically, when punched, the area of the adhesive that adheres to the portion other than the adhesive on the cut surface is 20% of the area of the adhesive layer. There was a problem that the following control method was not described and that it was not practical.

Therefore, the present inventors have made earnest efforts in view of the above circumstances, and have made a machinability-improving film comprising a substrate and an active energy ray-curable machinability-improving layer, and an active energy ray By setting the gel fraction (G1) of the machinability-improving layer after irradiation to a value equal to or higher than a predetermined value, a cutting device or the like is used to cut the resin plate, which is one of the base materials. It has been found that good machinability and the like can be obtained even when the mechanical film and the machinability improving layer are cut.
Further, the adhesive strength (P1) of the machinability-improving layer before irradiation with active energy rays is set to a predetermined value or more, and the adhesive strength (P2) of the machinability-improving layer after irradiation with active energy rays is set to a predetermined value or more. The present inventors have also found that good durability can be obtained by this, and that the problem of durability as well as the above-described problem of machinability can be solved, thus completing the present invention.
That is, the present invention provides a machine capable of obtaining excellent machinability (cuttability) and durability when simultaneously machining (cutting, etc.) a base material together with a resin plate such as a touch panel or a liquid crystal display device. An object of the present invention is to provide a workability-improving film, a laminate obtained by attaching such a machinability-improving film to a resin plate, and an efficient method of using such a machinability-improving film.

According to the present invention, it is composed of a substrate and an active energy ray-curable machinability improving layer containing a reaction product of an active energy ray-curable component and a crosslinkable component, and adhesive strength before active energy ray irradiation. Let (P1) be a value of 1 N/25 mm or more.
At the same time, the adhesive strength (P2) after irradiation with active energy rays is set to a value of 10 N/25 mm or more, and the gel fraction (G1) of the machinability improving layer after irradiation of active energy rays is set to a value of 75% or more. A machinability-enhancing film characterized by is provided to solve the above-mentioned problems.
That is, the machinability-improving film is configured in this way, the adhesive strength (P1) before irradiation with active energy rays is set to a predetermined value or more, and the gel fraction of the machinability-improving layer after irradiation with active energy rays By setting (G1) to a value equal to or greater than a predetermined value, even when the machinability-improving film is cut at the same time while the resin plate is included, the gap between the machinability-improving film and the resin plate The interface is very clear and good machinability can be obtained.
In addition, by setting the adhesive strength (P2) after irradiation with active energy rays to a predetermined value or more, good durability is obtained when the machinability improving layer is attached to a resin plate such as a touch panel or a liquid crystal display device. can also be obtained.

In forming the machinability-improved film of the present invention, the reactant of the crosslinkable component is a (meth)acrylic acid ester copolymer derived from a reactive functional group-containing monomer and a (meth)acrylic acid alkyl ester monomer. and a thermal cross-linking agent.
By forming the reactant of the crosslinkable component in this manner, good reactivity can be maintained, and cohesive strength of the machinability-enhancing layer can be easily obtained.

In forming the machinability-improved film of the present invention, the reactive functional group-containing monomer is preferably a hydroxyl group-containing monomer or a carboxy group-containing monomer.
By having such a reactive functional group-containing monomer, the reactivity with the crosslinkable component can be made excellent, and a good crosslinked structure can be easily formed.
As a result, the resulting machinability-enhancing layer has relatively high film strength and good machinability.

Another aspect of the present invention is a laminate comprising any one of the machinability-improving films described above attached to a resin plate.
In the case of a laminate including such a resin plate and machinability-enhancing film, various functional films used in various devices can be precisely machined (cut) together with the resin plate through the machinability-enhancing layer. processing) to easily produce a laminate such as a functional film with a resin plate.

Moreover, in forming the laminate of the present invention, the resin plate is preferably an optical resin plate.
If it is a laminate containing such an optical resin plate, in optical devices such as touch panels and liquid crystal display devices, various functional films used in them can be precisely machined (cut) together with the optical resin plate. processing), and through the machinability improving layer, it can be produced as a functional film with an optical resin plate or the like.

Further, still another aspect of the present invention is a method of using any one of the machinability-improved films described above, wherein the machinability-improved film includes the following steps (1) to (3): How to use.
(1) Step of attaching a machinability-improving film to a resin plate (2) Step of irradiating an active energy ray to cure an active energy ray-curable component (3) Lamination including a machinability-improving layer and a resin plate By using the machinability improving film in this way, when manufacturing a resin plate with a functional film in a touch panel or a liquid crystal display device, a cutting device can be used. When the resin plate and the functional film are machined through the machinability-improving layer using a mechanical processing apparatus such as Good machinability (cuttability, durability, etc.) can be obtained.

FIGS. 1(a) and 1(b) are diagrams provided for explaining configuration examples of laminates each using a machinability-enhancing film. FIGS. 2A to 2E are diagrams provided for explaining a method for manufacturing a machinability-improved film including a thermal crosslinking step and a method for manufacturing a laminate using the machinability-improved film. . FIGS. 3(a) to 3(f) are diagrams provided for explaining the production process and the use process of a laminate using a functional film as a base material and a film for improving machinability (part 1 ). FIGS. 4(a) to 4(f) are diagrams provided for explaining the steps of creating and using another laminate using a release film as a base material and a machinability-improving film ( Part 2).

[First embodiment]
The first embodiment of the present invention, as exemplified in FIGS. It is a machinability-enhancing film 18 comprising a (functional film, etc.) 16 .
The adhesive strength (P1) of the machinability improving layer 14 in a state of being laminated on the resin plate 12 before the active energy ray irradiation is 1 N/25 mm or more, and the adhesive strength after the active energy ray irradiation. A machinability-improving film characterized by having (P2) a value of 10 N/25 mm or more and a gel fraction of a machinability-improving layer 14' after irradiation with an active energy ray of 75% or more. is 18.
Hereinafter, the machinability-enhancing film 18 of the first embodiment will be specifically described for each component with reference to the drawings as appropriate.
Note that FIG. 1(a) illustrates a mode of a laminate 10 composed of a resin plate 12 laminated with a machinability improving film 18, and FIG. 1(b) shows another laminate. 10, showing an example of a touch panel having a predetermined space 14a in a part of the machinability improving layer 14 (however, electric wiring etc. are omitted).

1. Resin Plate (1) Type The type of the resin plate 12 shown in FIG. It is preferable to use

Examples of such resin plates include polyester resin plates such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene resin plates, polypropylene resin plates, diacetylcellulose resin plates, triacetylcellulose resin plates, and acetylcellulose butyrate resin plates. , polyvinyl chloride resin plate, polyvinylidene chloride resin plate, polyvinyl alcohol resin plate, ethylene-vinyl acetate copolymer resin plate, polystyrene resin plate, polycarbonate resin plate, polymethylpentene resin plate, polysulfone resin plate, polyether ether ketone Resin plates, polyethersulfone resin plates, polyetherimide resin plates, polyimide resin plates, fluororesin plates, polyamide resin plates, acrylic resin plates, norbornene resin plates, cycloolefin resin plates, and the like.

Among these, polyester resin plate, polycarbonate resin plate, polymethylpentene resin plate, polysulfone resin plate, acrylic resin plate, and polyether resin plate have excellent optical properties and heat resistance and are excellent in dimensional stability. More preferably, it is at least one of an ether ketone resin plate, a polyimide resin plate, a norbornene resin plate, and a cycloolefin resin plate.
In addition, acrylic resin plates (MMA resin plates, etc.) and polycarbonate resin plates are particularly preferred because they are excellent in transparency, mechanical strength, flexibility, workability, weather resistance, and economic efficiency. More preferred.

(2) Thickness It is preferable that the thickness of the resin plate 12 shown in FIG.
The reason for this is that if the thickness of the resin plate 12 is less than 200 μm, the strength of the resin plate 12 may be reduced, or the arrangement fixability of the touch panel including the resin plate 12 may be reduced. be.
On the other hand, when the thickness of the resin plate 12 exceeds 10000 μm, the resin plate 12 and the functional film or the like as the base material 16 are simultaneously machined through the machinability improving layers 14 and 14′. This is because it may be difficult to
Therefore, it is more preferable to set the thickness of the resin plate 12 to a value within the range of 500 to 5000 μm, and more preferably to a value within the range of 700 to 2000 μm.

(3) Optical Properties Regarding the optical properties of the resin plate 12, it is preferable that the resin plate 12 has transparency to the extent that it can be used for applications such as touch panels and liquid crystal display devices.
Specifically, if the visible light transmittance of the resin plate 12 is excessively low, the yield may be remarkably lowered, or the types of usable constituent materials may be excessively limited.
Therefore, the lower limit of the visible light transmittance of the resin plate 12 is preferably 60% or more, more preferably 75% or more, and even more preferably 85% or more.
On the other hand, the upper limit of the visible light transmittance of the resin plate 12 is usually 100% or less, preferably 99.9% or less, more preferably 99% or less, and 98% or less. is more preferable.

(4) Additives In the resin plate 12, antioxidants, hydrolysis inhibitors, ultraviolet absorbers, inorganic fillers, organic fillers, inorganic fibers, organic fibers, and conductive additives are added to improve the durability, physical properties, mechanical properties, and the like. It is also preferable to add at least one known additive such as a conductive material, an electrically insulating material, a metal ion scavenger, a weighting agent, a filler, an abrasive, a coloring agent, a viscosity modifier, and the like.
When these known additives are blended into the resin plate, the blending amount is usually set to 0 with respect to the total amount (100% by weight) of the resin plate 12, although it depends on the type of the additive. A value in the range of 1 to 30% by weight is preferable, a value in a range of 0.5 to 20% by weight is more preferable, and a value in a range of 1 to 10% by weight is preferable. More preferred.

2. Machinability-improving layer The machinability-improving layer 14 in the present embodiment includes a (meth)acrylic acid ester copolymer as a main agent (A), a crosslinkable component (B), and an active energy ray-curable component (C ) as an essential component and is derived from a composition for forming the machinability improving layer 14 (sometimes referred to as a precursor).
That is, the machinability-improving layer 14 is composed of a (meth)acrylic acid ester copolymer as the main agent (A) and a crosslinkable component (B), which is a reaction product composed of a crosslinked structure formed by heat, and It is composed of a curing active energy ray-curable component (C). The active energy ray-curable component (C) crosslinks the machinability-improving layer 14 by irradiating the active energy ray, thereby forming a crosslinked structure that is intricately entangled with the reaction product. A machinability improving layer 14' can be obtained.

In this specification, "(meth)acrylate" means both acrylate and methacrylate, and the same applies hereinafter, including other similar terms.
Components (A) to (E), etc., constituting the machinability improving layer 14 and its precursor will be specifically described below.

(1) Main agent (A)
The type of the main agent (A) that constitutes the machinability-improving layer 14 and its precursor is not particularly limited.
However, for example, since it is easily available and easily mixed (compatible) with the active energy ray-curable component (C) described later, a (meth)acrylic acid ester derived from a predetermined (meth)acrylic acid ester monomer component It is preferable that the copolymer is the main agent (A).

When the main agent (A) is a (meth)acrylic acid ester copolymer, a monomer having a reactive group in the molecule that reacts with the crosslinkable component (B) as a monomer unit constituting the copolymer ( It is preferable to contain a reactive functional group-containing monomer) and a (meth)acrylic acid alkyl ester.
The reason for this is that the reactive group derived from the reactive group-containing monomer reacts with the crosslinkable component (B) to form a crosslinked structure (three-dimensional network structure), thereby achieving the desired storage elastic modulus and gel fraction. is easily satisfied, it is possible to obtain the machinability improving layer 14 having a relatively high film strength.

(1)-1 Monomer 1 (reactive functional group-containing monomer)
Examples of reactive group-containing monomers constituting a part of the (meth)acrylic acid ester polymer as the main agent (A) include monomers having a hydroxyl group in the molecule (hereinafter sometimes referred to as hydroxyl group-containing monomers), molecules A monomer having a carboxy group in the molecule (hereinafter sometimes referred to as a carboxy group-containing monomer), a monomer having an amino group in the molecule (hereinafter sometimes referred to as an amino group-containing monomer), and the like.
Among these, from the viewpoint of excellent reactivity with the crosslinkable component (B) and less adverse effect on the adherend, even if the weight average molecular weight of the hydroxyl group-containing monomer and (meth)acrylic acid ester copolymer is relatively low A carboxyl group-containing monomer is preferred from the viewpoint that the desired cohesive force is exhibited and the adhesive force and the gel fraction easily satisfy the desired values.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and hydroxyalkyl (meth)acrylates such as 3-hydroxybutyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate.
Among these, from the viewpoint of the reactivity between the hydroxyl group and the crosslinkable component (B) in the obtained (meth)acrylic acid ester copolymer, and the copolymerizability with other monomers, (meth)acrylic acid 2 -hydroxyethyl and 4-hydroxybutyl (meth)acrylate are preferred, and 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferred. These may be used alone or in combination of two or more.

In addition, the amount of the hydroxyl group-containing monomer as a monomer unit is preferably 1% by weight or more, preferably 10% by weight or more, relative to the total amount of monomers (100% by weight, hereinafter the same). is more preferable, more preferably 15% by weight or more, and preferably 20% by weight or more from the viewpoint of achieving desired values of the gel fraction increase rate and the like.
Furthermore, the amount of such hydroxyl group-containing monomers is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less, relative to the total amount of monomers.
That is, when the (meth)acrylic acid ester copolymer contains a hydroxyl group-containing monomer in a predetermined range as a monomer unit, it becomes easier to react appropriately with the crosslinkable component (B), and a good crosslinked structure is formed. .
As a result, the obtained machinability-improving layer 14 easily satisfies the desired storage elastic modulus and gel fraction, and thus has relatively high film strength and good machinability.

Examples of carboxy group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid.
Among these, acrylic acid is preferable from the viewpoint of the reactivity between the carboxyl groups in the resulting (meth)acrylic acid ester copolymer and the crosslinkable component (B) and the copolymerizability with other monomers. These may be used alone or in combination of two or more.
Then, when a carboxy group-containing monomer is included as a monomer unit, the (meth)acrylic acid ester copolymer preferably contains 1% by weight or more of the carboxy group-containing monomer with respect to the total amount of the monomers. It is particularly preferably contained in an amount of 8% by weight or more, and more preferably 8% by weight or more.
Furthermore, the (meth)acrylic acid ester copolymer preferably contains 30% by weight or less, more preferably 20% by weight or less, of a carboxy group-containing monomer as a monomer unit constituting the polymer. It is more preferable to contain 15% by weight or less.
That is, by containing a carboxyl group-containing monomer as a monomer unit in a predetermined range, it becomes easier to react favorably with the crosslinkable component (B), and a good crosslinked structure is formed.
As a result, the resulting machinability-enhancing layer 14 easily satisfies the desired storage elastic modulus and gel fraction, and has good machinability.

It is also preferable that the monomer units contain a small amount of a carboxy group-containing monomer or do not contain any at all.
The reason for this is that the carboxyl group is an acid component, and by not containing a carboxyl group-containing monomer, the adhesive may cause problems due to the acid, such as a transparent conductive film such as tin-doped indium oxide (ITO). This is because even if there is a metal film or the like, it is possible to suppress the problems (corrosion, resistance value change, etc.) caused by the acid.
However, it is permissible to contain a predetermined amount of the carboxy group-containing monomer to the extent that such problems do not occur.
Specifically, in the (meth)acrylic acid ester copolymer, as a monomer unit, a carboxy group-containing monomer is 5% by weight or less, preferably 1% by weight or less, more preferably 0.1% by weight or less. Allowed to contain.

Examples of amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate.
These may be used alone or in combination of two or more.
Then, when an amino group-containing monomer is included as a monomer unit, the (meth)acrylic acid ester copolymer preferably contains 1% by weight or more of the amino group-containing monomer with respect to the total amount of the monomers. It is particularly preferably contained in an amount of 8% by weight or more, and more preferably 8% by weight or more.
Furthermore, the (meth)acrylic acid ester copolymer preferably contains 30% by weight or less, more preferably 20% by weight or less, of an amino group-containing monomer as a monomer unit constituting the polymer. It is more preferable to contain 15% by weight or less.
That is, by containing the amino group-containing monomer as a monomer unit in a predetermined range, it becomes easier to react favorably with the crosslinkable component (B), and a good crosslinked structure is formed.
As a result, the resulting machinability-enhancing layer 14 easily satisfies the desired storage elastic modulus and gel fraction, and has good machinability.

(1)-2 Monomer 2 ((meth)acrylic acid alkyl ester monomer)
The (meth)acrylic acid ester copolymer as the main agent (A) may contain a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the copolymer. preferable.
Thereby, the machinability improving layer 14 can exhibit preferable adhesiveness.
In addition, the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms preferably has a linear or branched structure from the viewpoint of exhibiting more preferable adhesiveness.

The (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms preferably has a glass transition temperature (Tg) of less than 0° C. as a homopolymer (hereinafter sometimes referred to as a low Tg alkyl acrylate). be.).
The reason for this is that the adhesiveness of the resulting machinability-improving layer 14 can be further improved by containing such a low-Tg alkyl acrylate as a constituent monomer unit.

Examples of low Tg alkyl acrylates include n-butyl acrylate (Tg-55°C), n-octyl acrylate (Tg-65°C), isooctyl acrylate (Tg-58°C), 2- ethylhexyl (Tg-70°C), isononyl acrylate (Tg-58°C), isodecyl acrylate (Tg-60°C), isodecyl methacrylate (Tg-41°C), n-lauryl methacrylate (Tg-65°C), tridecyl acrylate (
Tg-55°C), tridecyl methacrylate (Tg-40°C) and the like are preferred.
Among these, from the viewpoint of more effectively improving the adhesiveness, as the low Tg alkyl acrylate, it is more preferable that the Tg of the homopolymer is −25° C. or less, and −50° C. or less. It is even more preferable to have
Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

In addition, the (meth)acrylic acid ester copolymer preferably contains a low Tg alkyl acrylate as a monomer unit constituting the polymer in an amount of 30% by weight or more as a lower limit, particularly 40% by weight or more. is more preferable, and it is even more preferable to contain 50% by weight or more.
The reason for this is that when such a low-Tg alkyl acrylate is blended, the resulting machinability improving layer 14 can be improved in adhesion, and the adhesion to the resin plate 12 can be improved. Because we can.
Further, the (meth)acrylic acid ester copolymer preferably contains 99% by weight or less, particularly 90% by weight or less, of a low-Tg alkyl acrylate as a monomer unit constituting the polymer. is more preferable, and it is even more preferable to contain 80% by weight or less.
The reason for this is that by blending such a low Tg alkyl acrylate, it is possible to introduce a suitable amount of other monomer components (especially reactive functional group-containing monomers) into the (meth)acrylic acid ester polymer. be.

In addition, the (meth)acrylic acid ester polymer is a monomer having a glass transition temperature (Tg) exceeding 0 ° C. as a homopolymer (hereinafter sometimes referred to as a high Tg alkyl acrylate), which constitutes the polymer. It is also preferable to use them together.
The reason for this is that the obtained machinability-improving layer 14 is imparted with an appropriate cohesive force, the desired storage elastic modulus and gel fraction can be easily satisfied, and machinability can be improved.

However, the high Tg alkyl acrylate described here excludes alicyclic structure-containing monomers and nitrogen-containing monomers, which will be described later.
Examples of such high Tg alkyl acrylates include methyl acrylate (Tg: 10°C), methyl methacrylate (Tg: 105°C), ethyl methacrylate (Tg: 65°C), n-butyl methacrylate (Tg: 20°C), isobutyl methacrylate (Tg: 48°C), t-butyl methacrylate (Tg: 107°C), n-stearyl acrylate (Tg: 30°C), n-stearyl methacrylate (Tg: 38°C), etc. acrylic monomer, vinyl acetate (Tg: 32°C), styrene (Tg: 30°C), and the like.
Among these, methyl methacrylate is particularly preferred as the high-Tg alkyl acrylate because it can impart appropriate cohesiveness to the machinability-improving layer 14 and facilitate the expression of desired storage elastic modulus and gel fraction. is preferred.

That is, when the (meth)acrylic acid ester polymer contains the high Tg alkyl acrylate as a monomer unit constituting the polymer, the high Tg alkyl acrylate is added to 1% by weight with respect to the total amount of the monomer components. It is more preferable to contain at least 3% by weight, more preferably at least 3% by weight.
In addition, the (meth)acrylic acid ester polymer preferably contains 20% by weight or less, more preferably 12% by weight or less, of the high Tg alkyl acrylate as a monomer unit constituting the polymer. It is more preferable to contain 8% by weight or less.
The reason for this is that by using the high Tg alkyl acrylate together with the low Tg alkyl acrylate in the amounts described above, the obtained machinability improving layer 14 exhibits suitable adhesiveness and cohesive strength, and the adhesion This is because the desired values of the force and the gel fraction are easily satisfied, and the desired durability is easily satisfied.

(1)-3 Monomer 3 (alicyclic structure-containing monomer)
The (meth)acrylic acid ester copolymer as the main agent (A) contains a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) as a monomer unit constituting the copolymer. is preferred.
The reason for this is that the alicyclic structure-containing monomer is bulky in terms of molecular structure, and it is presumed that the presence of this in the copolymer widens the distance between the polymers. This is because, as a result, the resulting machinability improving layer 14 can have excellent flexibility.
Therefore, when the (meth)acrylic acid ester polymer contains an alicyclic structure-containing monomer as a monomer unit, the machinability-improving layer 14 obtained by cross-linking the composition easily exhibits desired adhesiveness. As a result, the bonding property to the resin plate 12 is excellent.

In addition, the carbon ring of the alicyclic structure in the alicyclic structure-containing monomer may have a saturated structure or may partially have an unsaturated bond.
Moreover, such an alicyclic structure may be a monocyclic alicyclic structure, or may be a polycyclic alicyclic structure such as bicyclic or tricyclic.
In the obtained (meth)acrylic acid ester copolymer, from the viewpoint of widening the distance between the polymers and effectively exhibiting the flexibility of the machinability improving layer 14, the above alicyclic structure is a polycyclic alicyclic structure. A cyclic structure (polycyclic structure) is preferred.
Furthermore, the above polycyclic structure is particularly preferably bicyclic to tetracyclic, because the (meth)acrylic acid ester copolymer has good compatibility with other components.

In the same manner as described above, from the viewpoint of effectively exhibiting the flexibility of the adhesive, the number of carbon atoms in the alicyclic structure (meaning the number of all carbon atoms in the portion forming the ring, and (meaning the total number of carbon atoms, if present) is usually preferably 5 or more, more preferably 7 or more.
On the other hand, although the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, it is preferably 15 or less, more preferably 10 or less, from the viewpoint of compatibility as described above.

Therefore, the alicyclic structure contained in the alicyclic structure-containing monomer includes, for example, a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isobornyl skeleton, a cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubane skeleton, basketane skeleton, hausan skeleton, spiro skeleton, and the like.

Among these, from the viewpoint of obtaining better durability, a dicyclopentadiene skeleton (the number of carbon atoms in the alicyclic structure: 10), an adamantane skeleton (the number of carbon atoms in the alicyclic structure: 10) or an isobornyl skeleton (alicyclic structure) Those containing 7 carbon atoms in the cyclic structure are preferred, and those containing an isobornyl skeleton are more preferred.
Therefore, as the alicyclic structure-containing monomer, a (meth)acrylic acid ester monomer containing the above skeleton is preferable. Specifically, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, (meth)acrylic acid At least one of dicyclopentenyloxyethyl and the like is included.
Moreover, among these, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, or isobornyl (meth)acrylate are preferred from the viewpoint of obtaining better durability, and isobornyl (meth)acrylate is preferred. More preferred, isobornyl acrylate is particularly preferred.

In addition, the (meth)acrylic acid ester copolymer preferably contains 1% by weight or more of an alicyclic structure-containing monomer with respect to the total amount of monomers as a monomer unit constituting the copolymer. It is more preferably contained in an amount of 8% by weight or more, and more preferably 8% by weight or more.
Similarly, the (meth)acrylic acid ester copolymer preferably contains 40% by weight or less of an alicyclic structure-containing monomer as a monomer unit constituting the copolymer, and may contain 30% by weight or less. More preferably, it is contained in an amount of 24% by weight or less, and from the viewpoint of exhibiting the desired adhesive strength, gel fraction, and storage elastic modulus to improve durability, it is contained in an amount of 18% by weight or less. is particularly preferred.
When the content of the alicyclic structure-containing monomer is within the above range, the resulting machinability improving layer 14 has good flexibility and is more excellent in bonding to the resin plate 12. Therefore, it becomes easier to satisfy the desired adhesive strength and storage elastic modulus, and it becomes easier to exhibit good durability.

(1)-4 Monomer 4 (nitrogen atom-containing monomer)
The (meth)acrylic acid ester copolymer as the main agent (A) preferably contains a monomer having a nitrogen atom in its molecule (nitrogen atom-containing monomer) as a monomer unit constituting the copolymer.
The amino group-containing monomers exemplified as reactive group-containing monomers are excluded from the nitrogen atom-containing monomers. By allowing the nitrogen atom-containing monomer to exist in the copolymer as a structural unit, the reaction between the acrylic acid ester copolymer and the crosslinkable component (B) can be promoted, and the machinability improving layer 14 has polarity. It is possible to increase the cohesive strength of the machinability improving layer 14 and facilitate the development of desired adhesive strength, gel fraction and storage elastic modulus.

Examples of the nitrogen atom-containing monomers include monomers having a tertiary amino group, monomers having an amide group, and monomers having a nitrogen-containing heterocyclic ring. Among these, monomers having a nitrogen-containing heterocyclic ring are preferred.
Monomers having such a nitrogen-containing heterocyclic ring include, for example, N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth) ) acryloylpyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide At least one such as
Among these, N-(meth)acryloylmorpholine is preferred, and N-acryloylmorpholine is more preferred, from the viewpoint of obtaining superior adhesive strength.

Nitrogen atom-containing monomers other than the above-mentioned nitrogen-containing heterocyclic ring-containing monomers include, for example, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl (meth)acrylamide, ) acrylamide, N,N-dimethyl (meth)acrylamide, N,N-ethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-phenyl (meth)acrylamide , dimethylaminopropyl (meth)acrylamide, N-vinylcaprolactam, dimethylaminoethyl (meth)acrylate, and the like.

Then, the (meth)acrylic acid ester copolymer preferably contains 1% by weight or more of the nitrogen atom-containing monomer, more preferably 2% by weight or more, based on the total amount of the monomer components, and 4% by weight. % or more is more preferable.
Further, the (meth)acrylic acid ester copolymer preferably contains 40% by weight or less, more preferably 30% by weight or less, of a nitrogen atom-containing monomer as a monomer unit constituting the copolymer. It is more preferable to contain 20% by weight or less, and the desired adhesive strength, gel fraction and storage elastic modulus are exhibited to make the durability more excellent, so it is particularly preferable to contain 10% by weight or less. preferable.
When the content of the nitrogen atom-containing monomer is within the above range, the resulting machinability-improving layer 14 has effectively improved cohesive strength, and desired adhesive strength, gel fraction, and storage elastic modulus. This is because it becomes easy to exhibit the above, and the durability becomes excellent.

(1)-5 Monomer 5 (other monomers)
The (meth)acrylic acid ester copolymer as the main component (A) may, if necessary, contain other monomers different from the monomer components described above as monomer units constituting the copolymer.
As such other monomers, monomers containing no reactive functional groups are preferred.
Examples include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, vinyl acetate, and styrene. These may be used alone or in combination of two or more.
The polymerization mode of the (meth)acrylic acid ester copolymer may be a random copolymer or a block copolymer.

(1)-6 Weight average molecular weight When the main component (A) constituting the precursor of the machinability improving layer 14 is a (meth)acrylic acid ester copolymer, the weight average molecular weight (Mw) is 50,000 to 50,000. A value within the range of 2.5 million is preferred.
The reason for this is that when the weight-average molecular weight of the (meth)acrylic acid ester copolymer is less than 50,000, the cohesive force is reduced, resulting in peeling from the resin plate 12 or markedly reduced adhesiveness. This is because
On the other hand, if the weight-average molecular weight of the (meth)acrylic acid ester copolymer exceeds 2,500,000, handling may become difficult, and bonding to the resin plate 12 may deteriorate.
Therefore, the weight average molecular weight of the (meth)acrylic acid ester copolymer is more preferably in the range of 100,000 to 1,800,000, more preferably in the range of 300,000 to 1,000,000, and 40 to 80 Values in the range of 10,000 are most preferred.
The weight-average molecular weight of the main component of the machinability-enhancing layer 14 can be determined by GPC (gel permeation chromatography) by comparing with a calibration curve prepared in advance for standard polystyrene particles.

(1)-7 Polymerization of (meth)acrylic acid ester copolymer The (meth)acrylic acid ester copolymer as the main agent (A) is obtained by polymerizing a mixture of monomers constituting the polymer by a conventional radical polymerization method. It can be manufactured by
Polymerization of such a (meth)acrylic acid ester copolymer can be carried out by a solution polymerization method or the like using a polymerization initiator if desired.
Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of the polymerization initiator for polymerizing the (meth)acrylic acid ester copolymer include azo compounds and organic peroxides, and two or more of them may be used in combination.
More specifically, the azo compounds include, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane 1- carbonitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis(2- methyl propionate), 4,4′-azobis(4-cyanovaleric acid), 2,2′-azobis(2-hydroxymethylpropionitrile), 2,2′-azobis[2-(2-imidazoline -2-yl)propane] and the like.

Examples of organic peroxides include benzoyl peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, and di(2-ethoxyethyl). peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.
In addition, in the polymerization step, the weight average molecular weight of the obtained polymer can be adjusted to a desired value by blending a chain transfer agent such as 2-mercaptoethanol.

(2) Crosslinkable component (B)
When the composition containing the crosslinkable component (B) is heated, the crosslinkable component (B) undergoes a crosslink reaction with the (meth)acrylic acid ester copolymer as the main component (A) to form a crosslinked structure (three-dimensional network structure). Thereby, the machinability improving layer 14 having a relatively high film strength can be obtained.
The type of such a crosslinkable component (B) may be one that reacts with the main component (A) (for example, a (meth)acrylic acid ester copolymer, etc.), preferably the main component (A .
The crosslinkable component (B) may be one that reacts with heat, or one that reacts with active energy rays such as ultraviolet rays and electron beams. 14 is preferably a heat-crosslinkable component that undergoes a heat-crosslinking reaction with the main agent (A) (e.g., (meth)acrylic acid ester copolymer, etc.) from the viewpoint of facilitating the expression of the desired adhesive strength and gel fraction. .
Examples of the thermally crosslinkable component that undergoes a thermal crosslinking reaction with the main agent (A) (e.g., (meth)acrylic acid ester copolymer, etc.) include thermal crosslinking agents such as isocyanate-based crosslinking agents, epoxy-based crosslinking agents, Amine cross-linking agent, melamine cross-linking agent, aziridine cross-linking agent, hydrazine cross-linking agent, aldehyde cross-linking agent, oxazoline cross-linking agent, metal alkoxide cross-linking agent, metal chelate cross-linking agent, metal salt cross-linking agent, ammonium salt at least one such as a system cross-linking agent.
The type of these crosslinkable components (B) may be selected according to the reactivity of the reactive groups of the main component (A).
For example, when the reactive group of the main agent (A) is a hydroxyl group, it is preferable to blend an isocyanate-based cross-linking agent having excellent reactivity with the hydroxyl group.
Moreover, when the reactive group which the main agent (A) has is a carboxy group, it is preferable to use an epoxy-based cross-linking agent having excellent reactivity with the carboxy group.
In addition, a crosslinkable component (B) can be used individually by 1 type or in combination of 2 or more types.

Moreover, the isocyanate-based cross-linking agent preferably contains at least a polyisocyanate compound.
Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; Polyisocyanates, etc., their biuret forms, isocyanurate forms, and adduct forms which are reaction products with low-molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. mentioned. Among these, from the viewpoint of reactivity with hydroxyl groups, at least one of trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylene diisocyanate is preferable.

Examples of epoxy-based cross-linking agents include 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol di At least one of glycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine and the like can be mentioned.
Among these, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane is particularly preferred from the viewpoint of reactivity with carboxy groups.

Also, the amount of the crosslinkable component (B) to be blended is preferably within the range of 0.05 to 10 parts by weight with respect to 100 parts by weight of the main component (A).
The reason for this is that when the amount of the crosslinkable component (B) is less than 0.05 parts by weight, the reactivity with the hydroxyl groups and carboxy groups introduced into the main component (A) is significantly reduced, resulting in This is because the cohesive force of the machinability improving layer 14 cannot be obtained, and adhesiveness may not be exhibited in some cases.
As a result, the machinability improving layer 14 may be separated from the resin plate 12, or the adhesiveness may be remarkably lowered.
On the other hand, if the amount of the crosslinkable component (B) exceeds 10 parts by weight, it will react excessively with the hydroxyl groups and carboxyl groups introduced into the main component (A), resulting in the machinability improving layer 14. The cohesive force of is too high, and the adhesiveness may be significantly reduced.
Therefore, it is more preferable to set the amount of the crosslinkable component (B) in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the main component (A), and more preferably 0.3 to 1 part by weight. A value within the range is more preferable.

(3) Active energy ray-curable component (C)
The machinability improving layer 14 in this embodiment preferably contains an active energy ray-curable component (C).
When such a machinability improving layer 14 is applied to an adherend (resin plate 12) and then irradiated with an active energy ray, the photopolymerization initiator (D) described later is cleaved, and the active energy ray Polymerization of the curable component (C) is accelerated.
It is presumed that the polymerized active energy ray-curable component (C) is entwined with the crosslinked structure (three-dimensional network structure) formed by cross-linking the main agent (A) and the crosslinkable component (B).
Therefore, the machinability-improving layer 14' having such a higher-order structure easily satisfies the desired adhesive strength, storage elastic modulus and gel fraction, and has excellent durability under high-temperature and high-humidity conditions. become a thing.

Here, the active energy ray-curable component (C) is not particularly limited as long as it causes a curing reaction upon irradiation with an active energy ray and provides the above effects.
Moreover, the active energy ray-curable component (C) may be a monomer, an oligomer, a polymer, or a mixture thereof.
Among these, polyfunctional acrylate-based monomers having a weight-average molecular weight of less than 1,000, which are excellent in compatibility with the main agent (A) and the like, are preferred.

More specifically, the polyfunctional acrylate monomer having a weight average molecular weight of less than 1000 is preferably an acrylate monomer having 2 to 6 reactive functional groups.
Examples of acrylate-based monomers having two reactive functional groups include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate ) acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acryloyl At least one of oxyethoxy)phenyl]fluorene and the like can be mentioned.

Examples of acrylate-based monomers having three reactive functional groups include trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, and pentaerythritol tri(meth)acrylate. At least one of meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, etc. .

Furthermore, examples of acrylate-based monomers having four reactive functional groups include diglycerin tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate.
Examples of the acrylate-based monomer having five reactive functional groups include at least one such as propionic acid-modified dipentaerythritol penta(meth)acrylate.
Examples of the acrylate-based monomer having six reactive functional groups include at least one of dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like.

Among these, acrylate-based monomers having 3 to 6 reactive functional groups are particularly preferable from the viewpoint of durability of the machinability improving layer 14 .
Specifically, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate are particularly preferred.

As the active energy ray-curable component (C), it is also preferable to use an active energy ray-curable acrylate-based oligomer.
Examples of such acrylate oligomers include at least one of polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, silicone acrylate, and the like.
The weight average molecular weight of such an acrylate oligomer is preferably 50,000 or less, more preferably 500 to 50,000, even more preferably 3,000 to 40,000.

Moreover, as the active energy ray-curable component (C), it is also preferable to use an adduct acrylate polymer in which a group having a (meth)acryloyl group is introduced into the side chain.
Such an adduct acrylate polymer uses a copolymer of a (meth)acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and a part of the crosslinkable functional group of the copolymer is , (meth)acryloyl group and a compound having a group reactive with a crosslinkable functional group.
The weight average molecular weight of the adduct acrylate polymer is preferably about 50,000 to 900,000, more preferably about 100,000 to 500,000.

In the present embodiment, the active energy ray-curable component (C) is preferably the polyfunctional acrylate-based monomer described above, and one type is selected from the polyfunctional acrylate-based monomer, acrylate-based oligomer, and adduct acrylate-based polymer. or two or more of them may be used in combination, or these components may be used in combination with other active energy ray-curable components.

The amount of the active energy ray-curable component (C) is generally preferably in the range of 1 to 50 parts by weight per 100 parts by weight of the main component (A).
The reason for this is that when the amount of the active energy ray-curable component (C) is less than 1 part by weight, the reactivity becomes poor, making it difficult to achieve the desired storage elastic modulus and gel fraction. This is because good machinability may not be obtained.
On the other hand, if the amount of the active energy ray-curable component (C) exceeds 50 parts by weight, the reactivity cannot be controlled and the component reacts excessively with the main component (A), resulting in a dense crosslinked structure. This is because there is a case where the adhesive strength is lowered and good durability cannot be obtained.
Therefore, the lower limit of the amount of the active energy ray-curable component (C) is preferably 3 parts by weight or more, particularly preferably 6 parts by weight or more, relative to 100 parts by weight of the main component (A). , 10 parts by weight or more.
On the other hand, the upper limit of the amount of the active energy ray-curable component (C) is preferably 30 parts by weight or less, particularly preferably 20 parts by weight or less, and further preferably 13 parts by weight or less. .

(4) Photoinitiator (D)
Since the active energy ray-curable component (C) can be efficiently cured by irradiation with an active energy ray, it is preferable to contain a photopolymerization initiator (D) as desired.

Examples of such photoinitiators (D) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2 -phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio ) Phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichloro Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4- Diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide At least one such as

Among these, when ultraviolet rays are used as the active energy ray, it is preferable to contain a photopolymerization initiator (D) having an absorption wavelength outside the ultraviolet absorption wavelength range. ) more preferably contains a photopolymerization initiator (D) having an absorption wavelength in the wavelength region of 380 nm to 410 nm. preferably contains 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and the like.
The reason for this is as follows.
Since mobile electronic devices equipped with touch panels and the like are often used outdoors, there is a problem that their constituent members deteriorate due to the influence of ultraviolet rays.
In order to solve this problem, a method of suppressing deterioration due to the influence of ultraviolet rays is sometimes taken by incorporating a member having an ultraviolet absorbing ability (ultraviolet shielding member) into the electronic device.
When the ultraviolet shielding member is incorporated in an electronic device in this way and ultraviolet rays are irradiated from the side of the ultraviolet shielding member, the machinability improving layer 14 contains a photopolymerization initiator ( When D) is used, ultraviolet rays are shielded by the ultraviolet shielding member, making it impossible to cure the machinability improving layer 14 .
Conversely, in such a case, if a photopolymerization initiator (D) having absorption wavelengths outside the ultraviolet absorption wavelength region is used in the machinability improving layer 14, wavelengths outside the ultraviolet absorption wavelength region can be used. This is because it can be sufficiently hardened by

The amount of the photopolymerization initiator (D) is preferably within the range of 0.5 to 25 parts by weight with respect to 100 parts by weight of the active energy ray-curable component (C). A value in the range of up to 20 parts by weight is more preferable, and a value in the range of 5 to 15 parts by weight is even more preferable.

(5) Silane coupling agent (E)
The composition for forming the machinability improving layer 14 preferably further contains a silane coupling agent (E).
This is because, when the adherend includes a glass member or a resin member, the adhesion between the machinability improving layer 14 and the adherend is improved.
Therefore, the machinability-enhancing layer 14 containing the silane coupling agent (E) is more excellent in durability under high-temperature and high-humidity conditions.

Here, as the type of silane coupling agent (E), an organosilicon compound having at least one alkoxysilyl group in the molecule and having optical transparency is preferred.
Examples of such silane coupling agents (E) include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane; silicon compounds having an epoxy structure such as silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Mercapto group-containing silicon compound; amino such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane Group-containing silicon compound; 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these and alkyl such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane Examples include condensates with group-containing silicon compounds. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Also, the amount of the silane coupling agent (E) to be blended is preferably within the range of 0.01 to 5 parts by weight per 100 parts by weight of the main agent (A).
The reason for this is that if the amount of the silane coupling agent (E) to be blended is less than 0.01 part by weight, it may be difficult to obtain the blending effect.
On the other hand, when the amount of the silane coupling agent (E) exceeds 5 parts by weight, the silane coupling agent (E) causes the hydroxyl groups and carboxyl groups introduced into the main agent (A) to , and the crosslinkable component (B) may react excessively, resulting in a marked decrease in adhesiveness.
Therefore, the blending amount of the silane coupling agent (E) is preferably set to a value within the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the main agent (A), and 0.2 to 1 part by weight. It is more preferable to set the value within the range of

(6) Additives In order to further improve the machinability-enhancing properties and mechanical properties of the machinability-enhancing layer 14, in addition to the silane coupling agent (E) described above, inorganic fillers, organic fillers, inorganic fibers, and organic fibers are added. , conductive materials, electrically insulating materials, metal ion scavengers, lightening agents, thickeners, fillers, abrasives, coloring agents, antioxidants, hydrolysis inhibitors, ultraviolet absorbers, etc. It is also preferable to blend the additive of
When these known additives are blended, the blending amount is usually set to a value within the range of 0.1 to 50% by weight with respect to the total amount (100% by weight) of the main agent (A). is preferred, and a value within the range of 0.5 to 30% by weight is more preferred.

(7) Thickness The thickness of the machinability improving layer 14 is preferably set to a value within the range of 3 to 40 μm.
The reason for this is that if the thickness of the machinability-enhancing layer is less than 3 μm, the desired adhesiveness cannot be exhibited, and there is a tendency for the adhesion to the resin plate 12 to deteriorate.
On the other hand, if the thickness of the machinability-enhancing layer 14 exceeds 40 μm, machinability may deteriorate, or the adhesive strength before and after the active energy ray irradiation may be adjusted to a value within the desired range. This is because it may become difficult.
Therefore, the thickness of the machinability-enhancing layer 14 is more preferably set to a value within the range of 8 to 30 μm, and more preferably set to a value within the range of 10 to 20 μm.

3. Substrate Although the type of substrate 16 is not particularly limited, it is usually a resin film, and functional films and release films are typical among them.

When the base material 16 is a functional film, its types include a decorative film in a touch panel, a polarizing film in a liquid crystal display device, a retardation film, a light diffusion film, a light control film, an antiglare film, a photocatalytic film, At least one of ultraviolet shielding film, heat shielding film, antistatic film, conductive film, half-mirror film, hard coat film, decorative film, holographic film and the like can be mentioned.
The various functional films described above have various functions (decorative properties, light polarization properties, light phase properties, light diffusion properties, light control properties) on the surface of PET film, PEN film, acrylic film, polycarbonate film, or TAC film. , anti-glare properties, UV shielding properties, heat shielding properties, anti-static properties, conductivity, half-mirror properties, hard coating properties, decorative properties, holographic properties, etc.). is appropriately selected depending on the purpose.

The thickness of the functional film as the base material 16 is determined in consideration of the application, light transmittance, etc., and is usually preferably in the range of 10 to 300 μm.
The reason for this is that if the thickness of the functional film is less than 10 μm, the mechanical strength and durability may be remarkably lowered.
On the other hand, if the thickness of the functional film exceeds 300 μm, the sensitivity may be lowered and the transparency of active energy rays may be significantly lowered when used in a touch panel or the like.
Therefore, the thickness of the functional film is more preferably in the range of 20-250 μm, more preferably in the range of 30-190 μm.

When the base material 16 is a release film, its type is at least one of a polyester film having a release surface (PET film, etc.), an olefin film, an acrylic film, a urethane film, a polycarbonate film, a TAC film, a fluorine film, a polyimide film, and the like. One is mentioned.
The release surface in this specification includes both a surface that has been subjected to a release treatment and a surface that exhibits releasability without being subjected to a release treatment.

The thickness of the release film as the base material 16 is determined in consideration of the application, light transmittance, etc., but it is usually preferable to set the thickness within the range of 10 to 300 μm.
The reason for this is that if the release film has a thickness of less than 10 μm, the mechanical strength and durability may be significantly reduced.
On the other hand, if the thickness of the release film exceeds 300 μm, the release film may roll up or become difficult to handle.
Therefore, the thickness of the release film is more preferably in the range of 20 to 250 μm, more preferably in the range of 30 to 200 μm.

As for the optical properties of the base material (functional film, release film, etc.) 16, it is preferable to have transparency suitable for applications such as touch panels and liquid crystal display devices.
That is, the lower limit of the visible light transmittance of the resin plate 12 is preferably 60% or more, more preferably 75% or more, and even more preferably 85% or more.
The upper limit of the visible light transmittance of the resin plate 12 is usually 100% or less, preferably 99.9% or less, more preferably 99% or less, and 98% or less. is more preferable.

4. Various physical properties of the machinability-enhancing layer (1) Storage modulus (M1) before active energy ray irradiation
The machinability improving layers 14, 14' according to the present embodiment preferably have a storage elastic modulus (M1) before irradiation with active energy rays within a range of 0.01 to 1 MPa.
The reason for this is that by controlling the above-mentioned storage modulus (M1) within a predetermined range, the flexibility of the machinability-improving layer 14 before irradiation with active energy rays becomes appropriate, and the lamination property to the resin plate 12 is improved. It is because it becomes a good thing.
Therefore, it is more preferable to set the storage modulus (M1) before active energy ray irradiation to a value within the range of 0.04 to 0.20 MPa, and furthermore, to achieve both durability and machinability after active energy ray irradiation. It is more preferable to set the value within the range of 0.07 to 0.08 MPa because it is easy to
In this specification, unless otherwise specified, it means the storage elastic modulus (M1, M2) corresponding to a temperature of 25°C (the same shall apply hereinafter).

(2) Storage modulus after active energy ray irradiation (M2)
In the machinability improving layers 14 and 14' according to the present embodiment, it is preferable to set the storage elastic modulus (M2) after irradiation with active energy rays to a value of 0.10 MPa or more.
The reason for this is that by controlling the storage modulus (M2) to a value of 0.10 MPa or more, when the machinability improving film 18 is bonded to the resin plate 12 and cut using a cutting device, This is because the occurrence of chipping and protrusion derived from the machinability-enhancing layer is suppressed, and good machinability can be obtained.
Therefore, the lower limit of the storage modulus (M2) is preferably 0.20 MPa or more, more preferably 0.25 MPa or more, and even more preferably 0.30 MPa or more.
On the other hand, if the value of the storage elastic modulus (M2) mentioned above is excessively large, the durability may decrease. Therefore, the upper limit of the storage modulus (M2) is preferably 5 MPa or less, more preferably 2 MPa or less, particularly preferably 1 MPa or less, and 0.6 MPa or less. It is more preferable that

(3) Increase rate of storage modulus (M2/M1×100)
The machinability-improving layers 14 and 14' according to the present embodiment have an increase rate (=M2/M1 ×100) is usually preferably set to a value within the range of 320 to 30000%.
The reason for this is that by controlling the increase rate (%) of the storage elastic modulus described above to a value within a predetermined range, the bonding property to the resin plate 12 before the active energy ray irradiation and the durability before and after the active energy ray irradiation are improved. This is because it is easy to achieve both of the durability and the machinability.
Therefore, the increase rate (%) of storage elastic modulus is more preferably set to a value within the range of 350 to 10000%, and more preferably set to a value within the range of 380 to 1000%.

(4) Gel fraction before active energy ray irradiation (G1)
The machinability-enhancing layers 14, 14' in the present embodiment preferably have a gel fraction (G1) before irradiation with active energy rays, usually within a range of 40 to 78%.
The reason for this is that by controlling the gel fraction (G1) to a value within a predetermined range, the adhesion to the resin plate 12 can be improved.
More specifically, when the gel fraction (G1) is less than 40%, the machinability-improving film 18 may be difficult to handle due to insufficient cohesion of the machinability-improving layer 14 .
On the other hand, when the gel fraction (G1) described above exceeds 78%, the machinability improving layer 14 becomes too hard, and the adhesion to the resin plate 12 may deteriorate.
Therefore, it is more preferable to set the gel fraction to a value within the range of 50 to 76%, and more preferably to a value within the range of 60 to 70%.

(5) Gel fraction after active energy ray irradiation (G2)
The machinability improving layers 14 and 14' according to the present embodiment are characterized by having a gel fraction (G2) of 75% or more after irradiation with active energy rays.
The reason for this is that if the gel fraction (G2) is less than 75%, the machinability may be remarkably lowered and adhesive residue may occur.
Therefore, the lower limit of the gel fraction (G2) is more preferably 77% or more, particularly preferably 79% or more, and even more preferably 80% or more.
The upper limit of the gel fraction (G2) is not particularly limited, but it may be 100%, but from the viewpoint of achieving both machinability and durability, it is preferably 95% or less, and 90% or less. Especially preferred.
A method for measuring the gel fraction (G2) will be described in detail in the examples below.

(6) Increase rate of gel fraction (G2/G1×100)
In the machinability improving layers 14 and 14' according to the present embodiment, the increase rate (=G2/G1 ×100) is usually preferably set to a value within the range of 110 to 250%.
The reason for this is that by controlling the increase rate of the gel fraction to a value within a predetermined range, the bonding property to the resin plate 12 before the active energy ray irradiation becomes suitable, and after the active energy ray irradiation This is because the durability and the machinability in are easily compatible with each other.
More specifically, when the increase rate of the gel fraction is less than 110%, the machinability deteriorates, chipping occurs in the machinability improving layers 14 and 14', and the durability deteriorates. sometimes.
On the other hand, if the increase rate of the gel fraction exceeds 250%, the machinability improving layers 14, 14' may become brittle and crack.
Therefore, the increase rate of the gel fraction is more preferably in the range of 114 to 200%, more preferably in the range of 120 to 160%, and more preferably in the range of 128 to 140%. value is particularly preferred.

(7) Adhesive strength before active energy ray irradiation (P1)
The machinability-enhancing film 18 according to the present embodiment is characterized by having an adhesive strength (P1) of 1 N/25 mm or more before irradiation with active energy rays.
The reason for this is that the adhesion to the resin plate 12 is improved by controlling the adhesive force (P1) to a value within a predetermined range.
If the adhesive strength (P1) is less than 1 N/25 mm, it becomes difficult to bond the resin plate 12 in the first place. In some cases, problems such as peeling off may easily occur.
On the other hand, such adhesive strength (P1) is preferably 60 N/25 mm or less.
This is because when the adhesive strength (P1) exceeds 60 N/25 mm, the handleability tends to deteriorate.
Therefore, it is more preferable to set the adhesive strength (P1) to a value within the range of 8 to 40 N/25 mm, and more preferably to a value of 15 to 30 N/25 mm.
The adhesive strength (P1) can be measured by a 180-degree peeling method according to JIS Z0237:2009 before irradiation with active energy rays, but a more specific measuring method is described in Examples described later. As shown.

(8) Adhesive strength after active energy ray irradiation (P2)
The machinability-enhancing film 18' according to the present embodiment is characterized by having an adhesive strength (P2) of 10 N/25 mm or more after irradiation with active energy rays.
The reason for this is that by controlling the adhesive strength (P2) to a value of 10 N/25 mm or more, good adhesion can be obtained and excellent durability can be exhibited.
Therefore, the lower limit of the adhesive strength (P2) is preferably 15 N/25 mm or more, more preferably 20 N/25 mm or more, and even more preferably 24 N/25 mm or more.
On the other hand, the upper limit of the adhesive strength (P2) is preferably 200 N/25 mm or less, more preferably 120 N/25 mm or less, and even more preferably 60 N/25 mm or less. A value of 40 N/25 mm or less is particularly preferred.
The adhesive strength (P2) can be measured by a 180-degree peeling method according to JIS Z0237:2009 after irradiation with active energy rays, but a more specific measuring method is described in Examples described later. As shown.

(9) Increase rate of adhesive strength (= P2 / P1 × 100)
The machinability-improving films 18 and 18' according to the present embodiment have an increase rate (=P2/P1×100 ) is preferably set to a value of 80 to 300%.
The reason for this is that by controlling the rate of increase in adhesive strength to a value within a predetermined range, both the bonding property to the resin plate 12 before irradiation with active energy rays and the durability after irradiation with active energy rays are more compatible. This is because it becomes easier.
Therefore, it is more preferable to set the rate of increase in adhesive strength to a value within the range of 100 to 200%, and more preferably to a value within the range of 120 to 140%.

(10) maximum stress (S2)
The machinability-improving film 18' according to the present embodiment preferably has a maximum stress (S2) of 1.5 N/mm ² or more when the tensile stress after irradiation with active energy rays is measured. .
The reason for this is that by setting the maximum stress (S2) to a value of 1.5 N/mm ² or more, chipping of the machinability improving layer 14′ tends to be suppressed during machining, and machinability is good. This is because
Therefore, the maximum stress (S2) is more preferably set to a value of 2.0 N/mm ² or more, and more preferably set to a value of 2.5 N/mm ² or more from the viewpoint of compatibility with durability.
On the ^other hand, the ^upper limit of the maximum stress (S2) is not particularly limited. is more preferable, and it is particularly preferable to set the value to 4 N/mm ² or less.

(11) Stress at 100% elongation (E2)
The machinability-improving film 18' according to the present embodiment preferably has a stress (E2) at 100% elongation after irradiation with active energy rays of generally 10 N/mm ² or less.
The reason for this is that by setting the stress at 100% elongation (E2) to a value of 10 N/mm ² or less, the machinability-improving layer 14′ tends to be difficult to stretch during machining, and machinability after cutting. This is because it is possible to obtain a cut surface in which the improvement layer 14' does not protrude, thereby improving machinability.
Therefore, it is more preferable to set the upper limit of the stress at 100% elongation (E2) to a value of 6 N/mm ² or less, and from the viewpoint of compatibility with durability, it is preferable to set the value to 1 N/mm ² or less. More preferred.
On the other hand, the lower limit of the stress at 100% elongation (E2) is not particularly limited, but from the viewpoint of achieving both durability and machinability, a value of 0.1 N / mm ² or more is preferable, and 0.4 N /mm ² or more, and particularly preferably 0.7 N/mm ² or more.

5. Laminate The laminate 10, 10' using the machinability-improving films 18, 18' according to the present embodiment is formed by laminating the machinability-improving films 18, 18' shown in FIG. As long as it is a laminate composed of the resin plates 12, it is not particularly limited.
Therefore, various functional films used in various devices are precisely machined (cut) together with the resin plate 12 through the machinability improving layer 14', and the functional film with the resin plate is laminated. It can easily be manufactured as a body 10, 10'.
Hereinafter, aspects of such laminates 10 and 10' will be specifically described.

(1) Laminate before active energy ray curing Laminate 10 before active energy ray curing is shown in FIGS. , a functional film as a substrate 16, a machinability improving film 18, and a resin plate 12 are sequentially laminated.
2 to 4 will be specifically described as a method of using the machinability improving films 18, 18', which will be described later.

(2) Laminate after active energy ray curing The laminate 10′ after active energy ray curing is obtained by applying an active energy ray from the base material 16 of the laminate 10 before active energy ray curing or the resin plate 12 side. By irradiating, the machinability-improving layer 14 can be made into a machinability-improving layer 14' after curing.
That is, as shown in FIGS. 2(d) and 2(e), FIGS. 3(e) and 3(f), FIGS. 4(e) and 4(f), the functional film as the substrate 16 , a cured machinability improving layer 14 ′, and a resin plate 12 are sequentially laminated to form a laminate 10 ′.

The cured machinability-improving layer 14' is obtained by curing the machinability-improving layer 14 of the machinability-improving film 18 described above by irradiation with active energy rays.
In the present embodiment, the cured machinability-improving layer 14′ has a crosslinked structure formed by heat of the (meth)acrylic acid ester copolymer as the main agent (A) and the crosslinkable component (B). It is composed of a pressure-sensitive adhesive containing a reaction product and a structure (polymerized structure) in which the active energy ray-curable component (C) is polymerized and cured.
It is presumed that the polymerized structure is entwined with a crosslinked structure composed of the (meth)acrylic acid ester copolymer as the main agent (A) and the crosslinkable component (B).
By having a structure in which a plurality of three-dimensional structures are intertwined, the machinability-improving layer 14' after curing has a high cohesive force, and easily satisfies the desired adhesion and gel fraction values. Become.
Therefore, the hardened machinability-enhancing layer 14' exhibits excellent machinability as well as excellent durability.

As long as the effects of the present invention can be obtained, the post-curing machinability-improving layer 14' contains a photopolymerization initiator (D) that has not been cleaved by active energy ray irradiation. good too.
In this embodiment, the residual amount of the photopolymerization initiator in the machinability improving layer 14' after curing is preferably 0.1% by mass or less, and more preferably 0.01% by mass or less. .

6. Method of use As a method of using the machinability-improving film 18, the desired machinability-improving film 18 is obtained in the preparatory step, as illustrated in FIGS. ) to (3) are preferably included.
(1) A step of attaching the obtained machinability-improving film 18 to the resin plate 12 (2) A step of irradiating an active energy ray from the resin plate 12 or base material 16 side to activate the machinability-improving layer 14 Step (3): Curing the energy ray-curable component to form a cured machinability-enhancing layer 14'; Step of Machining Treatment A method of using the machinability improving film 18 will be specifically described below with reference to the drawings as appropriate.

6-1: Preparation process (1)
The preparation step (1) is a step of preparing a composition for forming the machinability improving layer 14 .
Therefore, the resin layer 13 derived from the composition for forming the machinability improving layer 14 shown in FIG. , a composition comprising a crosslinkable component (B) and an active energy ray-curable component (C) as main components.
The composition may contain a photopolymerization initiator (D), a silane coupling agent (E), an organic solvent, etc., as necessary, and the resin layer 13 is formed by uniformly mixing these. A coating liquid can be obtained.

6-2: Preparation process (2)
The preparation step (2) is a step of applying a coating liquid containing the predetermined composition described above.
Therefore, as shown in FIG. 2( a ), the surface of a substrate (functional film or the like) 16 is coated with the coating liquid of the composition described above to form the substrate 16 and the machinability improving layer 14 . A laminate is obtained in which the resin layer 13 derived from the composition for the purpose is laminated.
The method of applying the coating liquid is not particularly limited, and can be performed by a known method. Examples include bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and the like. be done.
Then, as shown in FIG. 2(b), a predetermined heat treatment (H) is applied to cause a thermal cross-linking reaction between the functional groups contained in the main component (A) and the cross-linkable component (B), and the activation energy is A machinability-improving film 18 is obtained by forming the line-curing machinability-improving layer 14 .
The heat treatment (H) can also serve to remove scattering of the solvent or the like contained in the coating liquid of the composition described above.
At that time, specifically, the heating temperature of the heat treatment (H) is preferably 50 to 160°C, more preferably 70 to 140°C.
The heating time is preferably 10 seconds to 10 minutes, more preferably 50 seconds to 2 minutes.
Furthermore, after the heat treatment, it is preferable to provide a curing period of about 1 to 2 weeks at normal temperature (eg, 23° C., 50% RH).
By such heat treatment (and curing), the (meth)acrylate copolymer is satisfactorily crosslinked via the crosslinkable component (B) to form a crosslinked structure.
That is, through such steps, the machinability-improving layer 14 is obtained by thermally cross-linking the resin layer 13 derived from the composition for forming the machinability-improving layer 14, and the machinability-improving layer 14 is obtained. A property-enhancing film 18 is obtained.
Note that other components contained in the composition for forming the machinability improving layer 14 (active energy ray-curable component (C), photopolymerization initiator (D), coupling agent (E), etc.) The content, properties, etc. do not change before and after thermal crosslinking.

6-3: Step (1)
Next, step (1) is a step of laminating the machinability improving film 18 on the resin plate 12 .
Therefore, as shown in FIG. 2(c), the resin plate 12 and the machinability improving layer 14 of the machinability improving film 18 are bonded and laminated.
For bonding the resin plate 12 and the machinability improving film 18 as described above, a known bonding method such as a lamination method can be used.
Thereby, the laminate 10 in which the active energy ray-curable machinability improving layer 14 is sandwiched between the substrate (functional film or the like) 16 and the resin plate 12 can be obtained.

6-4: Step (2)
Next, step (2) is a step of irradiating active energy rays.
Therefore, as shown in FIG. 2(d), active energy rays (L) such as ultraviolet rays are irradiated from the surface of the substrate 16 opposite to the side in contact with the machinability improving layer.
As a result, the active energy ray-curable component (C) in the machinability-enhancing layer 14 is cured to form a cured machinability-enhancing layer 14'.
That is, it is possible to obtain the laminate 10 ′ in which the cured machinability improving layer 14 ′ is sandwiched between the substrate (functional film or the like) 16 and the resin plate 12 .
In FIG. 2D, the active energy ray (L) is irradiated from the back side of the resin plate 12, but the side on which the substrate (functional film, etc.) 16 is provided, that is, the resin side The active energy ray (L) may be irradiated from the opposite side, and further, from both the back side of the resin plate 12 and the substrate (functional film etc.) 16 side, the active energy ray (L) may be irradiated.

Here, the active energy ray refers to an electromagnetic wave or a charged particle beam that has energy quanta, and specifically includes ultraviolet rays, electron beams, and the like.
The active energy ray in this embodiment is preferably an active energy ray containing light having a wavelength of 200 to 450 nm.
In order to obtain an active energy ray that satisfies the above conditions, for example, a light source capable of irradiating ultraviolet rays, such as a high-pressure mercury lamp, a fusion H lamp, and a xenon lamp, may be used.
As for the irradiation amount of active energy rays, the illuminance is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less.
The amount of light is preferably 50 mJ/cm ² or more, more preferably 80 mJ/cm ² or more, and even more preferably 200 mJ/cm ² or more.
Also, the amount of light is preferably 10000 mJ/cm ² or less, more preferably 5000 mJ/cm ² or less, and even more preferably 2000 mJ/cm ² or less.

6-5: Step (3)
Finally, step (3) is the machining process step.
Therefore, as shown in FIG. 2(e), a resin plate 12 laminated with a substrate (functional film or the like) 16 and a machinability improving layer 14' is subjected to a predetermined machining process (for example, Cutting processing in the direction indicated by the arrow A) is performed.
Since the machinability-enhancing film 18 of the present embodiment has excellent machinability, it is possible to easily obtain a laminate 10' having a desired shape by a single cutting process.
Furthermore, since the machinability-enhancing layer 14' does not chip or stretch during the cutting process, the cut surface after processing is good, and the obtained laminate 10' has excellent appearance quality.
In addition, since the laminate 10' obtained has excellent durability, it can also be applied to optical components (for example, an in-vehicle touch panel, a liquid crystal display device, etc.) used in severe environments.
Therefore, by using the machinability-improving film 18 of the present embodiment as described above, a functional film having the machinability-improving layer 14 ′ interposed therebetween can be applied to optical components such as touch panels and liquid crystal display devices. It is possible to easily manufacture a resin plate with the .

7. Other Usage 7-1 Modification 1
The steps illustrated in FIGS. 3(a) to 3(f) are examples of steps in the case of using the substrate (release film, etc.) 16 in the preparation step (1) described above.
Therefore, for example, when using the base material (release film, etc.) 16, as illustrated in FIGS. The workability improving film 18 can be suitably used for machining processing (cutting processing).

(1) Preparatory step (1')
The preparation step (1') is a step of applying the resin layer 13 to the substrate and a heat treatment step.
That is, as shown in FIGS. 3A and 3B, a resin layer 13 derived from a composition for forming a machinability improving layer 14 is formed on the surface of a substrate (release film, etc.) 16. In this step, the machinability-enhancing film 18 ′ including the machinability-enhancing layer 14 is formed by coating and heat-treating (H).
Here, the preparation step and application step of the composition for forming the machinability improving layer 14 conform to the preparation step (1) and preparation step (2) described above.
In addition, although not shown, in FIG. 3B, a base material (release film, etc.) 16 may be provided on the exposed surface of the machinability improving layer 14 .
With such a configuration, the risk of contamination of the machinability-enhancing layer 14 before use is reduced.

(2) Step (1')
Next, step (1') is a step of laminating the machinability improving film 18' on the resin plate 12. As shown in FIG.
That is, as shown in FIGS. 3(c) and 3(d), the exposed surface of the machinability-improving layer 14 of the machinability-improving film 18′ and the base material (functional film) 16 are laminated. and stack them.
Then, the base material (separation film, etc.) 16 is peeled off, and the resin plate 12 is laminated.
As a result, the laminate 10 in which the active energy ray-curable machinability improving layer 14 is sandwiched between the substrate (functional film or the like) 16 and the resin plate 12 can be obtained.

(3) Step (2')
Next, step (2') is an active energy ray irradiation step.
Therefore, as shown in FIG. 3(e), the active energy ray (L) is irradiated to cure the active energy ray-curable component (C) contained in the machinability improving layer 14, thereby improving the machinability. Layer 14'. That is, it is possible to obtain the laminate 10 ′ in which the cured machinability improving layer 14 ′ is sandwiched between the substrate (functional film or the like) 16 and the resin plate 12 .
In addition, the irradiation conditions of the active energy ray and the like conform to the step (2) described above.

(4) Step (3')
Finally, step (3') is a machining process step.
Therefore, as shown in FIG. 3( f ), a resin plate 12 laminated with a substrate (functional film or the like) 16 and a machinability improving layer 14 ′ is subjected to a predetermined machining process (for example, arrow Cutting processing in the direction indicated by A) is performed.
Also in the steps (1′) to (3′) described above, the machinability improving films 18 and 18′ of the present embodiment can be suitably used in the same manner as in the steps (1) to (3) described above. can be done.
Therefore, also in Modification 1, it is possible to easily manufacture a resin plate with a functional film through the machinability improving layer 14', which is applicable to optical parts such as touch panels and liquid crystal display devices.

7-2 Modification 2
The steps illustrated in FIGS. 4A to 4F are examples of steps in which the machinability improving film 18' is laminated in a different order in the step (1') of Modification 1 described above.
That is, as shown in FIG. 4C, the exposed surface of the machinability improving layer 14 of the machinability improving film 18' shown in FIG. .
Then, as shown in FIG. 4D, the base material (separation film or the like) 16 is peeled off, and the base material (functional film) 16 is laminated. In addition, except for the step (1') described above, it conforms to the modified example 1 described above.
Therefore, in the modified example 2 as well, the machinability improving films 18 and 18' of the present embodiment are used in the same manner as the above-described steps (1) to (3) and the above-described steps (1') to (3'). It can be used preferably.
Therefore, even in the steps (1′) to (3′), a resin plate with a functional film, which is applicable to optical parts such as touch panels and liquid crystal display devices, is easily formed via the machinability improving layer 14′. can be manufactured to

Hereinafter, the machinability-improving film of the present embodiment and the method of using the machinability-improving film will be described in further detail with reference to examples.
However, the present embodiment is not limited to the description of these examples for no particular reason.

[Example 1]
1. Preparation and use of machinability-improved film 1-(1) Preparation of main agent (A) As monomer components, 30 parts by weight of n-butyl acrylate, 25 parts by weight of 2-ethylhexyl acrylate, and 10 parts by weight of isobornyl acrylate , 5 parts by weight of methyl methacrylate, 5 parts by weight of N-acryloylmorpholine, and 25 parts by weight of 2-hydroxyethyl acrylate are solution-polymerized to form a (meth)acrylic ester copolymer as the main agent (A). Adjusted coalescence.
The weight average molecular weight (Mw) of the obtained (meth)acrylic acid ester copolymer was measured by the method described below and found to be 500,000.

The weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
(Measurement condition)
・ GPC measurement device: HLC-8020 manufactured by Tosoh Corporation
・ GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
TSK gel G2000HXL
・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

Details such as abbreviations in Table 1 are as follows.
(Main agent (A): ((meth)acrylate copolymer))
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate IBXA: isobornyl acrylate MMA: methyl methacrylate ACMO: N-acryloylmorpholine HEA: 2-hydroxyethyl acrylate AA: 4HBA acrylic acid 4HBA: 4-hydroxy acrylate Butyl HEMA: 2-hydroxyethyl methacrylate

1-(2) Adjustment of composition for forming machinability-improving layer 0.3 parts by weight of trimethylolpropane-modified tolylene diisocyanate as (B) and 8 parts by weight of ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate as active energy ray-curable component (C). and 0.8 parts by weight of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as a photopolymerization initiator (D) and 3-glycidoxypropyltrimethoxy as a silane coupling agent (E). Silane was blended at a ratio of 0.3 parts by weight, stirred until uniform, and diluted with methyl ethyl ketone to obtain a coating solution having a solid content concentration of 30% by weight.

Details such as abbreviations in Table 1 are as follows.
(Crosslinkable component (B))
B1: trimethylolpropane-modified tolylene diisocyanate B2: trimethylolpropane-modified xylene diisocyanate B3: 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (active energy ray-curable component (C))
C1: ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate C2: trimethylolpropane triacrylate C3: dipentaerythritol hexaacrylate

1-(3) Step of Forming Machinability-Enhancing Layer The resulting coating solution was applied to a heavy-release type release film (manufactured by Lintec Corporation, product name "SP-PET752150 ”) was applied using a bar coater to a thickness of 15 μm after drying.
Then, the coating layer is heat-treated at 90° C. for 1 minute to promote a thermal cross-linking reaction. A machinability improving layer having a crosslinked structure was formed.

Next, the coated layer on the heavy release release film obtained above and a light release release film (manufactured by Lintec, product name “SP-PET382120”) obtained by releasing the polyethylene terephthalate film on one side with a silicone release agent. is laminated so that the release-treated surface of the light release release film is in contact with the machinability improving layer, and cured for 7 days under conditions of 23 ° C. and 50% RH to obtain a heavy release release. A machinability-improving film for evaluation consisting of a film/a machinability-improving layer (thickness: 15 μm)/lightly peelable release film was prepared.
The thickness of the machinability-enhancing layer is a value measured using a constant-pressure thickness gauge (manufactured by Teclock, product name "PG-02") in accordance with JIS K7130.

2. Evaluation of machinability-improving film 2-(1) Measurement of adhesive strength (P1) before irradiation with active energy ray Of the machinability-improving film for evaluation, peel off the light release type release film from the machinability-improving layer. , A polyethylene terephthalate (PET) film having an easy-adhesive layer (manufactured by Toyobo Co., Ltd., product name “PET A4300”, thickness: 100 μm). 15 μm)/PET film laminate was obtained.
The laminate thus obtained was cut into a piece having a width of 25 mm and a length of 150 mm, which was used as a sample.
In an environment of 23 ° C. and 50% RH, peel off the heavy release type release sheet from the sample obtained above, attach the exposed machinability improving layer to the glass plate, and then reciprocate a 2 kg roller once. crimped by
Then, after leaving it for 24 hours under the conditions of 23 ° C. and 50% RH, using a tensile tester (manufactured by Orientec, Tensilon), the adhesive strength (P1 , N/25 mm) were measured.
In addition, the conditions other than those described here were measured according to JIS Z 0237:2000. Table 2 shows the results.

2-(2) Measurement of adhesive strength (P2) after irradiation with active energy ray In an environment of 23 ° C. and 50% RH, the heavy release type release sheet was peeled off from the sample obtained above, and the exposed machinability After the improvement layer was attached to the glass plate, it was pressure-bonded by reciprocating a 2 kg roller once, and irradiated with ultraviolet rays as active energy rays from the PET film side under the following conditions.
Then, after leaving it for 24 hours under conditions of 23 ° C. and 50% RH, using a tensile tester (manufactured by Orientec, Tensilon), active energy ray irradiation was performed under the conditions of a peel speed of 300 mm / min and a peel angle of 180 degrees. Post adhesion (P2, N/25 mm) was measured.
In addition, the conditions other than those described here were measured according to JIS Z 0237:2000. Table 2 shows the results.
<Ultraviolet irradiation conditions>
・Using a high-pressure mercury lamp ・Illuminance 200mW/cm ² , Light intensity 2000mJ/cm ²
・Using “UVPF-A1” manufactured by Eye Graphics Co., Ltd. for UV illuminance and photometer

2-(3) Calculation of increase rate of adhesive strength Increase rate of adhesive strength (P2) after active energy ray irradiation with respect to adhesive strength (P1) before active energy ray irradiation measured above (= P2 / P1 × 100 , %) were calculated. Table 2 shows the results.

2-(4) Measurement of gel fraction (G1) before irradiation with active energy ray Of the obtained machinability-improving film for evaluation, only the machinability-improving layer was wrapped in a polyester mesh (mesh size 200), The mass was weighed with a precision balance, and the mass of the mesh alone was subtracted to calculate the mass of the machinability improving layer alone. Let the mass at this time be m1.
Next, the machinability-improving layer wrapped in the polyester mesh produced by the above method was immersed in ethyl acetate at room temperature (23° C.) for 72 hours.
After that, the machinability-enhancing layer wrapped in a polyester mesh was taken out, air-dried for 24 hours in an environment with a temperature of 23°C and a relative humidity of 50%, and further dried in an oven at 80°C for 12 hours. .
After drying, the mass was weighed with a precision balance to calculate the mass (m2) of the machinability-improving layer before irradiation with active energy rays.
Based on the mass calculated above, the gel fraction (G1) (=(m2/m1)×100, %) of the machinability improving layer before irradiation with active energy rays was derived. Table 2 shows the results.

2-(5) Measurement of Gel Fraction (G2) after Irradiation with Active Energy Rays After peeling off the light release type release film from the obtained machinability-improving film for evaluation, the exposed machinability-improving layer was subjected to The active energy ray was directly irradiated under the conditions described above to cure the machinability improving layer.
The mass of the cured machinability-improving layer was weighed with a precision balance, and the mass (m3) of the machinability-improving layer after irradiation with active energy rays was calculated.
Based on the mass calculated above, the gel fraction (G2) (=(m3/m1)×100, %) of the machinability-improving layer after irradiation with active energy rays was derived. Table 2 shows the results.

2-(6) Calculation of gel fraction increase rate Increase rate (= G2/ G1×100, %) was calculated. Table 2 shows the results.

2-(7) Measurement of maximum stress (S2) and stress at 100% elongation (E2) Peel off the light release type release film from the obtained machinability-improving film for evaluation, and measure the exposed machinability-improving layer. Then, an active energy ray was directly irradiated under the conditions described above to cure the machinability improving layer.
The maximum stress (S2, N/mm ² ) and the stress at 100% elongation (E2, N/mm ² ) of only this cured machinability-enhancing layer were measured using a tensile tester (manufactured by Orientec, Tensilon, peeling was measured using a speed of 200 mm/min).
The measurement was performed under conditions other than those described here in accordance with JIS K 7162-2:2014. Table 2 shows the results.

2-(8) Measurement of storage modulus (M1) before irradiation with active energy ray Of the obtained machinability-improved film for evaluation, only the machinability-improved layer was measured according to JIS K7244-4: 1999, Measure the storage modulus (M1, MPa (25°C)) of the machinability-enhancing layer before irradiation with active energy rays using a viscoelasticity measuring device (manufactured by TA Instruments, ARES, frequency 1 Hz). bottom. Table 2 shows the results.

2-(9) Measurement of storage elastic modulus (M2) after irradiation with active energy ray After peeling off the light-release type release film from the obtained machinability-improving film for evaluation, the exposed machinability-improving layer was subjected to The active energy ray was directly irradiated under the conditions described above to cure the machinability improving layer.
The storage elastic modulus (M2, MPa (25° C.)) of the machinability-improving layer after irradiation with active energy rays was measured under the same conditions as above for only this cured machinability-improving layer. Table 2 shows the results.

2-(10) Calculation of increase rate of storage elastic modulus Increase rate (= M2/ M1×100, %) was calculated. Table 2 shows the results.

2-(11) Evaluation of Machinability The light release type release sheet of the obtained film for improving machinability for evaluation was peeled off, and the exposed machinability improving layer was attached to a PET film (100 μm).
Furthermore, the heavy release type release sheet was peeled off, and the exposed machinability improving layer was attached to a PET film (100 μm) to obtain a test piece.
After curing the machinability improving layer by irradiating the active energy ray under the conditions described above, the test piece was cut vertically with respect to one PET film surface of the test piece using a cutter.
Then, the cut surface was observed under a microscope, and machinability was evaluated according to the following criteria.
A: No chipping or elongation of the machinability-enhancing layer was observed, and the cut surface was good.
◯: Slight chipping and elongation of the machinability-enhancing layer were observed, but the cut surface was practically satisfactory.
Δ: Chipping and elongation of the machinability-improving layer were observed, and the cut surface was practically not preferable.
x: Chipping and elongation of the machinability-enhancing layer were observed, and the cut surface was unusable.

2-(12) Evaluation of Durability The light release type release sheet of the obtained film for improving machinability for evaluation was peeled off, and the exposed machinability improving layer was treated with polymethyl methacrylate (PMMA) and polycarbonate (PC). was attached to the surface of the polycarbonate side of the laminated resin plate (thickness: 1 mm, containing an ultraviolet absorber).
Furthermore, a test piece was obtained by peeling the heavy-release type release sheet from the machinability-improving film for evaluation and attaching the exposed machinability-improving layer to a TAC film (thickness: 100 μm) as a functional film. rice field. The obtained test piece was autoclaved under conditions of 50° C. and 0.5 MPa for 30 minutes, and then allowed to stand at normal pressure, 23° C. and 50% RH for 24 hours.
Then, under the conditions described above, the resin plate side was irradiated with active energy rays to cure the machinability improving layer, and then stored under high temperature and high humidity conditions of 85° C. and 85% RH for 500 hours.
After that, lifting and peeling at the interface between the machinability-enhancing layer and the adherend was visually confirmed, and the durability was evaluated according to the following criteria. Table 2 shows the results.
⊚: Neither air bubbles nor floating and peeling can be observed.
◯: Although minute air bubbles are slightly generated, no large air bubbles or peeling can be confirmed.
x: Large air bubbles or floating peeling can be confirmed.

[Examples 2 to 9, Comparative Examples 1 to 4]
Composition and molecular weight of (meth)acrylic acid ester copolymer as main agent (A), type and amount of crosslinkable component (B), type and amount of active energy ray-curable component (C), initiation of photopolymerization A film with improved machinability was obtained in the same manner as in Example 1, except that the blending amount of the agent (D) and the blending amount of the silane coupling agent (E) were changed as shown in Table 1. An evaluation of the enhancement film was performed. Table 2 shows the results obtained.

As described in detail above, according to the machinability-improving film of the present invention, the adhesive strength (P1) of the machinability-improving layer before active energy ray irradiation, and the machinability after active energy ray irradiation By setting the gel fraction (G2) of the improving layer to a predetermined value or more, even when the machinability improving layer is cut at the same time while containing the resin plate using a mechanical processing device. , good machinability can be obtained.
In addition, in a predetermined machinability-improving film, by setting the adhesion (P2) of the machinability-improving layer after irradiation with active energy rays to a predetermined value, it is possible to obtain good durability to the resin plate. Became.

Then, a machinability-improving film provided with such a machinability-improving layer, a laminate including such a machinability-improving layer (resin plate to which the machinability-improving film is attached), and such a machine It has become possible to provide an efficient method of using the workability-enhancing film.
Therefore, the machinability-improving film of the present invention is expected to contribute to production efficiency improvement and quality improvement in touch panels, liquid crystal display devices, and the like.

10, 10': laminate 12: resin plate 13: resin layer 14: machinability-improving layer 14': machinability-improving layer after curing 16: base material 18, 18': machinability-improving film

Claims (8)

At least a substrate, a machinability improving layer (wherein the pressure-sensitive adhesive layer is a first pressure-sensitive adhesive layer as an outer layer on one side, a second pressure-sensitive adhesive layer as an outer layer on the other side, Except for the case where a third pressure-sensitive adhesive layer is positioned as an intermediate layer between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer), and can be,
and,
A machinability-improving film that is machined while being attached to a resin plate having a thickness of 200 to 10000 μm through the machinability-improving layer,
Contains an active energy ray-curable component and a reaction product of a crosslinkable component (however, when a photopolymerization initiator is included, a molecule having a structural site represented by the following formula (1) and a hydroxyl group in the molecule Excludes hydrogen-abstracting photopolymerization initiators.

[In the formula, R is any one atom or group selected from the group consisting of a halogen atom, a hydroxyl group, an alkoxy group, an alkyl group, and a phenyl group, and n is an integer of 0 to 5. However, when n is 2 or more, each R may be the same or different. ]) ,
The adhesive strength before irradiation with active energy rays is 1 N / 25 mm or more, and the adhesive strength after irradiation with active energy rays is 15 N / 25 mm or more,
and a machinability-improving film having an active energy ray-curable machinability-improving layer having a gel fraction of 75% or more when irradiated with the active energy ray. 2. The machinability-improving film according to claim 1, wherein the resin plate has a thickness in the range of 700 to 10,000 μm. The reaction product of the crosslinkable component is a reaction product of a (meth)acrylic acid ester copolymer derived from a reactive functional group-containing monomer and a (meth)acrylic acid alkyl ester monomer, and a thermal crosslinking agent. The machinability improving film according to claim 1 or 2 . 4. The machinability-improving film according to claim 3, wherein the reactive functional group-containing monomer is a hydroxyl group-containing monomer or a carboxy group-containing monomer. 4. The method according to claim 3, wherein the amount of the crosslinkable component is set to a value within the range of 0.05 to 10 parts by weight with respect to 100 parts by weight of the (meth)acrylic acid ester copolymer. Machinability improvement film. A laminate comprising the machinability-enhancing film according to any one of claims 1 to 5 attached to the resin plate. 7. The laminate according to claim 6, wherein the resin plate is an optical resin plate. A method of using the machinability-improving film according to any one of claims 1 to 5 , comprising the following steps (1) to (3).
(1) A step of attaching the machinability-improving film to the resin plate (2) A step of irradiating an active energy ray to cure the active energy ray-curable component (3) The machinability-improving layer and the resin A process of applying a machining treatment to a laminate including a plate

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