KR20190111755A - Direct bonding film, display element and method of producing display element - Google Patents

Abstract

The present invention relates to a direct bonding film which has an adhesive layer of an active energy ray hardness, wherein the ray transmittance of the adhesive layer in wavelength 380 nm is 40% or less, the gel fraction of an adhesive layer before active energy ray irradiation to the adhesive layer is 20 to 55%, the gel fraction of the adhesive layer after active energy ray irradiation to the adhesive layer is 40 to 90%, and the gel fraction of the adhesive layer after active energy ray irradiation with respect to the gel fraction of the adhesive layer before active energy ray irradiation is 1.05 or more.

Description

DIRECT BONDING FILM, DISPLAY ELEMENT AND METHOD OF PRODUCING DISPLAY ELEMENT}

TECHNICAL FIELD This invention relates to a direct bonding film, a display body, and a manufacturing method of a display body.

Direct bonding is a technique employ | adopted in manufacture of the display body (display) using the display module which has a liquid crystal element, a light emitting diode (LED) element, an organic electro luminescence (organic EL) element, etc.

In the display body, a protection panel for protecting the display module is disposed on the display module on which an image is displayed. Conventionally, the protection panel was arrange | positioned on the display module through the clearance gap (air gap) which consists of an air layer. Such a configuration facilitates the manufacture of the display body, but has a problem in that the display light from the display module is easily reflected in the air gap and the visibility of the image is deteriorated.

Therefore, direct bonding is performed in which the display module and the protective panel are bonded by an optically transparent adhesive, and the air gap between the display module and the protective panel is filled with an adhesive. By employing direct bonding, the contrast of the image can be increased, the visibility can be improved, and the non-glare can be reduced. In addition, since there is no air gap, the strength of the display becomes high, and condensation and the like can be prevented. The film-form adhesive used for such direct bonding is called a direct bonding film.

By the way, ultraviolet rays are not only harmful to the human body, but also deteriorate members and the like constituting the apparatus. Therefore, protecting a human body or an apparatus from ultraviolet rays by bonding a member having ultraviolet absorbing ability to a material (for example, glass) that transmits ultraviolet rays or by attaching the member in the apparatus. .

For example, Patent Document 1 discloses that a pressure-sensitive adhesive contains an ultraviolet absorber in a pressure-sensitive adhesive sheet bonded to window glass such as a vehicle or a building. The adhesive containing this ultraviolet absorber is obtained by the polymerization reaction using electron beam irradiation.

Moreover, as a device which should be protected from an ultraviolet-ray, various mobile electronic devices provided with display bodies, such as a mobile telephone, a smart phone, and a tablet terminal used outdoors, are illustrated. In the display body which a mobile electronic device is equipped with, a sensor is attached to a display body and the display body also serves as a touch panel in many cases.

As mentioned above, since the mobile electronic device is used outdoors, the structural member deteriorates under the influence of ultraviolet rays. In order to suppress such deterioration, the member which has an ultraviolet absorbing ability is mounted in an electronic device.

As such a member, it is known to give ultraviolet protection ability to the protective panel arrange | positioned at the surface side of an electronic device, and the adhesive which bonds another structural member. For example, Patent Literature 2 discloses that an adhesive sheet for bonding display member components constituting a display body has an ultraviolet absorbing layer.

Moreover, it is disclosed by patent documents 3-5 that the adhesive for bonding the display body structural members which comprise a display body is an ultraviolet curable type, and contains a ultraviolet absorber.

By the way, the adhesive for bonding display component members together has not only an ultraviolet absorbing ability but also a characteristic required from the shape of the display component member and the environment to which a display body is exposed.

For example, a frame-like printed layer is formed on the display module side of the protective panel, and may exist as a step in the thickness direction of the display. In the case of the direct bonding film which bonds a protective panel and a display module, when an adhesive layer which a direct bonding film has does not follow the step and bonds, an adhesive layer rises in the vicinity of a step | step, and a space | gap is formed. As a result, reflection loss of light occurs due to the voids, and the image quality of the display is deteriorated. Therefore, the step | following followability is calculated | required by the direct bonding film bonded to the protective panel which has a level | step difference.

Moreover, with thinning and weight reduction of an electronic device, the change of the protection panel from the conventional glass board to plastic boards, such as an acryl board and a polycarbonate board, is also examined. In the configuration in which the protective panel and the display module are bonded to each other by a direct bonding film, when the protective panel is changed to a plastic plate, outgas is generated from the plastic plate under high temperature and high humidity conditions, such as bubbles, floating, peeling, etc. There is a new problem of blistering. For this reason, in many cases, the blister resistance is calculated | required by the adhesive layer which the direct bonding film for bonding a display module and a protection panel has.

Japanese Unexamined Patent Publication No. 2013-249345 Japanese Laid-Open Patent Publication 2012-211305 Japanese Unexamined Patent Publication No. 2016-155981 Japanese Patent Publication 5307380 Japanese Patent Publication 5528861

Since the adhesive disclosed by patent document 1 is not an adhesive for bonding together the structural members of a display body, step difference followability is not considered at all.

Moreover, the adhesive sheet disclosed by patent document 2 has the structure which consists of a laminated | stacked adhesive layer and an ultraviolet absorber layer, and the structure which consists of an adhesive layer which has a ultraviolet absorber. However, when an adhesive layer contains a ultraviolet absorber, the adhesive is obtained by thermosetting an adhesive composition. This pressure-sensitive adhesive has a problem that the step tracking and the blister resistance are inferior.

The pressure-sensitive adhesive disclosed in Patent Literatures 3 to 5 had a problem that the step tracking and the blister resistance were not compatible at high levels.

This invention is made | formed in view of such a real thing, and an object of this invention is to provide the direct bonding film which can satisfy | fill favorable step difference tracking and favorable blister resistance, having ultraviolet absorbing power. Moreover, it aims at providing the display body comprised using the said direct bonding film, and its manufacturing method.

The first aspect of the present invention,

[1] A direct bonding film having an active energy ray curable pressure sensitive adhesive layer,

The light transmittance of the adhesive layer in wavelength 380nm is 40% or less,

Before active energy ray irradiation to an adhesive layer, the gel fraction of an adhesive layer is 20% or more and 55% or less,

After active energy ray irradiation to an adhesive layer, the gel fraction of an adhesive layer is 40% or more and 90% or less,

It is the direct bonding film characterized by the ratio of the gel fraction of the adhesive layer after active energy ray irradiation to the gel fraction of the adhesive layer before active energy ray irradiation being 1.05 or more.

[2] The direct bonding film according to [1], wherein the ratio of the storage elastic modulus of the pressure-sensitive adhesive layer after active energy ray irradiation to the storage elastic modulus of the pressure-sensitive adhesive layer before active energy ray irradiation is 1.20 or more.

[3] After the active energy ray irradiation to the pressure-sensitive adhesive layer, the storage elastic modulus of the pressure-sensitive adhesive layer is 0.05 MPa or more and 0.50 MPa or less, which is the direct bonding film according to [2].

[4] Before the active energy ray irradiation to the pressure-sensitive adhesive layer, the storage elastic modulus of the pressure-sensitive adhesive layer is 0.01 MPa or more and 0.20 MPa or less, The direct bonding film according to [2] or [3].

[5] The adhesive force of the pressure sensitive adhesive layer is 20 N / 25 mm or more after active energy ray irradiation to the pressure sensitive adhesive layer, which is the direct bonding film according to any one of [1] to [4].

[6] the pressure-sensitive adhesive layer,

A crosslinked structure composed of a (meth) acrylic acid ester copolymer and a thermal crosslinking agent,

An active energy ray curable component,

A photoinitiator whose absorbance at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass is 1.0 or more;

It is a direct bonding film in any one of [1]-[5] characterized by the adhesive which has a ultraviolet absorber.

[7] the direct bonding film has a release sheet,

Both main surfaces of an adhesive layer are comprised in contact with the peeling surface of a peeling sheet, It is a direct bonding film in any one of [1]-[6] characterized by the above-mentioned.

The second aspect of the present invention,

[8] a first display member,

A second indicator member,

A display body having a pressure-sensitive adhesive layer after curing bonding the first display member and the second display member to each other,

The adhesive layer after hardening is a display body characterized by hardening the adhesive layer which the direct bonding film in any one of [1]-[7] has hardened | cured.

[9] At least one of the first display member and the second display member has a step,

The adhesive layer after hardening is bonded together along the level | step difference, It is a display body as described in [8] characterized by the above-mentioned.

According to a third aspect of the present invention,

[10] a step of manufacturing a laminate formed by bonding the first display member and the second display member to each other via an adhesive layer included in the direct bonding film according to any one of [1] to [7]; ,

It is a manufacturing method of the display body characterized by having the process of irradiating an active energy ray to the adhesive layer of a laminated body, hardening an adhesive layer, and making it into an adhesive layer after hardening.

[11] At least one of the first display member and the second display member has a step,

An adhesive layer is a manufacturing method of the display body as described in [10] characterized by bonding together along a level | step difference.

ADVANTAGE OF THE INVENTION According to this invention, the direct bonding film which can satisfy favorable step tracking | following property and favorable blister resistance can be provided, having ultraviolet absorbing ability. Moreover, the display body comprised using the said direct bonding film and its manufacturing method can be provided.

1 is a cross-sectional view of a direct bonding film according to one embodiment of the present invention.
2 is a cross-sectional view of a laminate according to one embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on specific embodiment.

(1.direct bonding film)

As shown in FIG. 1, the direct bonding film 1 which concerns on this embodiment has the adhesive layer 11 and the peeling sheets 12a and 12b. This adhesive layer 11 is hardened | cured after active energy ray irradiation, and becomes an adhesive layer after hardening. The adhesive layer 11 consists of an adhesive mentioned later. Moreover, the two peeling sheets 12a and 12b are arrange | positioned so that the peeling surface may contact both main surfaces of the said adhesive layer. In other words, the adhesive layer 11 is clamped by two peeling sheets 12a and 12b. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability in a peeling sheet, and includes any of the surface which performed peeling process, and the surface which shows peelability, even without peeling process.

It is preferable that the thickness of the adhesive layer 11 is 20 micrometers or more, It is more preferable that it is 25 micrometers or more, It is further more preferable that it is 30 micrometers or more, It is especially preferable that it is 50 micrometers or more. On the other hand, the thickness is preferably 500 µm or less, more preferably 400 µm or less, still more preferably 300 µm or less, and particularly preferably 150 µm or less.

When thickness is too small, there exists a tendency for adhesive force to become small and it exists in the tendency for a step | following following traceability and a blister resistance to be inferior. On the other hand, when thickness is too big | large, there exists a tendency for workability to deteriorate.

(1.1.Adhesive)

In this embodiment, the adhesive layer 11 consists of an adhesive demonstrated below.

(1.2. Property of Adhesive)

In this embodiment, the adhesive which comprises the adhesive layer 11 has physical properties as shown below.

(1.2.1.light transmittance)

In this embodiment, the light transmittance of the adhesive in wavelength 380nm is 40% or less, 20% or less is preferable, and 10% or less is more preferable. The lower limit is not particularly limited, but is usually 0% or more. When the light transmittance of the pressure-sensitive adhesive is within the above range, at least a part of ultraviolet rays incident on the pressure-sensitive adhesive cannot penetrate the pressure-sensitive adhesive, so that the pressure-sensitive adhesive layer 11 made of the pressure-sensitive adhesive can exhibit good ultraviolet absorbing ability.

(1.2.2.Gel fraction before active energy irradiation)

In this embodiment, the gel fraction of an adhesive is changed before and after irradiation with an active energy ray. With the change of this gel fraction, the adhesive force and cohesiveness of an adhesive can be changed before and after active energy ray irradiation.

In this embodiment, it is preferable that the gel fraction of the adhesive before active energy ray irradiation is 20% or more, It is more preferable that it is 35% or more, It is still more preferable that it is 40% or more. Moreover, it is preferable that it is 55% or less, and, as for the said gel fraction, it is more preferable that it is 50% or less. The softness | flexibility of an adhesive becomes favorable because the gel fraction of the adhesive before active energy ray irradiation exists in the said range. As a result, it is possible to exhibit good step followability.

Therefore, when the adhesive layer which consists of an adhesive before active energy ray irradiation is bonded to the to-be-adhered body, it can fully follow the said step, and can suppress that a clearance gap or lifting arises between an to-be-adhered body and an adhesive.

(1.2.3.gel fraction after active energy ray irradiation)

Moreover, it is preferable that it is 40% or more, and, as for the gel fraction of the adhesive after active energy ray irradiation, ie, the gel fraction of the adhesive after hardening which comprises the adhesive layer after hardening, it is more preferable that it is 50% or more. Moreover, it is preferable that the said gel fraction is 90% or less, It is more preferable that it is 80% or less, It is preferable that it is 70% or less.

Since the gel fraction of the adhesive after hardening exists in the said range, there exists a tendency for the cohesion force of an adhesive layer after hardening to become high.

In addition, in this embodiment, the ratio of the gel fraction of the adhesive before active energy ray irradiation and the gel fraction of the adhesive after active energy ray irradiation is controlled to a predetermined range. Specifically, the ratio of the gel fraction of the pressure-sensitive adhesive after active energy ray irradiation to the gel fraction of the pressure-sensitive adhesive before active energy ray irradiation (gel fraction of pressure-sensitive adhesive after active energy ray irradiation / gel fraction of pressure-sensitive adhesive before active energy ray irradiation) is 1.05 or more. to be. That is, the gel fraction of the adhesive after hardening is higher than the gel fraction before irradiating an active energy ray. This is considered to be because an active energy ray curable component superposed | polymerized by irradiation of an active energy ray, and the superposition | polymerization structure was formed.

By setting the ratio of the gel fraction before and after active energy ray irradiation within the above range, the pressure-sensitive adhesive can exhibit good step-following properties before curing and can have a desirable cohesive force after curing. Therefore, in addition to the step tracking and blister resistance immediately after the adhesive layer is bonded to the adherend, the step tracking and the blister resistance under high temperature and high humidity conditions can be improved.

It is preferable that the ratio of the gel fraction before and behind said active energy ray irradiation is 1.08 or more, It is more preferable that it is 1.10 or more, It is further more preferable that it is 1.14 or more. On the other hand, the upper limit of the ratio of the gel fraction before and after active energy ray irradiation is not particularly limited, but in the present embodiment, it is preferably 5.0 or less, more preferably 2.0 or less, and even more preferably 1.50 or less.

In addition, what is necessary is just to measure the gel fraction of an adhesive by the method shown to the test example mentioned later.

(1.2.4.Storage modulus before irradiation with active energy rays)

In this embodiment, it is preferable that the storage elastic modulus of the adhesive before active energy ray irradiation measured by the frequency of 1 Hz is 0.20 Mpa or less, It is more preferable that it is 0.10 Mpa or less, It is further more preferable that it is 0.08 Mpa or less. On the other hand, the storage elastic modulus is preferably 0.01 MPa or more, more preferably 0.02 MPa or more, and even more preferably 0.04 MPa or more. Flexibility of an adhesive becomes favorable because the storage elastic modulus of the adhesive before active energy ray irradiation exists in the said range. As a result, it is possible to exhibit good step followability.

(1.2.5.Storage modulus after active energy radiation)

It is preferable that it is 0.50 Mpa or less, and, as for the adhesive after active energy ray irradiation measured by the frequency of 1 Hz, ie, the adhesive after hardening, it is more preferable that it is 0.20 Mpa or less. Moreover, it is preferable that the said storage elastic modulus is 0.05 Mpa or more, It is more preferable that it is 0.08 Mpa or more, It is still more preferable that it is 0.10 Mpa or more.

The storage elastic modulus of the adhesive after curing is about one order higher than the storage elastic modulus before irradiating an active energy ray. This is considered to be because the active energy ray curable component polymerized by irradiation of active energy rays to form a polymerized structure in the same manner as the gel fraction is increased. Since the storage elastic modulus of the adhesive after hardening exists in the said range, there exists a tendency for the cohesion force of an adhesive layer after hardening to become high.

Moreover, in this embodiment, it is preferable that the ratio of the storage elastic modulus of the adhesive before active energy ray irradiation, and the storage elastic modulus of the adhesive after active energy ray irradiation is in a predetermined range. Specifically, the ratio of the storage elastic modulus of the pressure-sensitive adhesive after active energy ray irradiation to the storage elastic modulus of the pressure-sensitive adhesive before active energy ray irradiation (the storage elastic modulus of the pressure-sensitive adhesive after active energy ray irradiation / active pressure-rays irradiation) is 1.20 It is preferable that it is above. That is, the storage elastic modulus of the adhesive after hardening is higher than the storage elastic modulus of the adhesive before irradiating an active energy ray.

By setting the ratio of the storage elastic modulus before and after active energy ray irradiation within the above range, the pressure-sensitive adhesive can exhibit good step-following properties before curing, and can have a desirable cohesive force after curing, in the same manner as the gel fraction described above. Therefore, in addition to the step tracking and blister resistance immediately after the adhesive layer is bonded to the adherend, the step tracking and the blister resistance under high temperature and high humidity conditions can be improved.

It is preferable that the ratio of storage elastic modulus before and behind said active energy ray irradiation is 1.20 or more, It is more preferable that it is 1.50 or more, It is further more preferable that it is 1.80 or more. On the other hand, the upper limit of the ratio of the storage elastic modulus before and after active energy ray irradiation is not particularly limited, but in this embodiment, it is preferable that it is 5.0 or less, It is more preferable that it is 3.0 or less, It is further more preferable that it is 2.0 or less. In addition, what is necessary is just to measure the storage elastic modulus of an adhesive by the method shown to the test example mentioned later.

(1.2.6.Adhesion after Activation Energy Ray Irradiation)

It is preferable that the lower limit of the adhesive force to the adhesive after active energy ray irradiation, ie, the soda-lime glass of the adhesive after hardening, is 20 N / 25 mm or more, It is more preferable that it is 30 N / 25 mm or more, It is 40 N / 25 mm or more More preferred. Moreover, although the upper limit of the said adhesive force is not specifically limited, Usually, it is preferable that it is 80 N / 25 mm or less, It is more preferable that it is 60 N / 25 mm or less, It is further more preferable that it is 50 N / 25 mm or less.

When the adhesive force of an adhesive after hardening is too small, it exists in the tendency for a blister resistance to fall. Moreover, it is easy to generate | occur | produce and peeling of an adhesive in a step vicinity vicinity, and there exists a tendency for the step | step traceability under high temperature, high humidity conditions to be inferior. The adhesive force in this specification basically means the adhesive force measured by the 180 degree peeling method based on JISZ0237: 2009, and the specific measuring method is as showing to the test example mentioned later.

(1.2.7.haze value after active energy ray irradiation)

It is preferable that the haze value of the adhesive after active energy ray irradiation, ie, the adhesive after hardening, is 5% or less, It is more preferable that it is 1% or less, It is further more preferable that it is 0.8% or less. If the haze value of the adhesive after hardening is 5% or less, transparency is high and it is preferable as an optical use (for a display body). Although the lower limit of the haze value of an adhesive after hardening is not specifically limited, Usually, it is 0% or more. In addition, the haze value in this specification is made into the value measured according to JISK7136: 2000, and the specific measuring method is as showing to the test example mentioned later.

(1.3.Structure and Composition of Pressure Sensitive Adhesive)

Although the structure and composition of an adhesive are not specifically limited, if the adhesive has said physical property, In this embodiment, it is preferable to have a structure and structural component shown below.

In the present embodiment, the pressure-sensitive adhesive has a crosslinked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B), and an active energy ray curable component (C) and aceto at a concentration of 0.1% by mass. It is preferable to contain the photoinitiator (D) whose ultraviolet absorbance of wavelength 380nm in a nitrile solution is 1.0 or more, and a ultraviolet absorber (E). In addition, in this specification, "(meth) acrylate" means both an acrylate and a methacrylate. Other similar terms are also the same.

This adhesive, Preferably, (meth) acrylic acid ester copolymer (A), a thermal crosslinking agent (B), an active energy ray curable component (C), and the wavelength 380 in the acetonitrile solution of 0.1 mass% of concentration. It is obtained by heat-processing and heat-crosslinking the adhesive composition containing the photoinitiator (D) and nm ultraviolet absorber (E) whose nm absorbance is 1.0 or more. Hereinafter, each component is demonstrated in detail.

(1.3.1. (Meth) acrylic acid ester copolymer)

It is preferable that the (meth) acrylic acid ester copolymer (A) contains the reactive group containing monomer which has a reactive group reacting with the heat crosslinking agent (B) mentioned later as a monomer unit which comprises the said copolymer in a molecule | numerator. The reactive group derived from this reactive group containing monomer reacts with a heat crosslinking agent (B), and a crosslinked structure (three-dimensional network structure) is formed, and the adhesive with comparatively high film strength can be obtained.

(1.3.1.1.Reactive group-containing monomers)

As said reactive group containing monomer, the monomer (hydroxyl group containing monomer) which has a hydroxyl group in a molecule | numerator is preferable. This is because the reactivity with the thermal crosslinking agent (B) is excellent and the adverse effects on the adherend are small.

As a hydroxyl-containing monomer, (meth) acrylic-acid 2-hydroxyethyl, (meth) acrylic-acid 2-hydroxypropyl, (meth) acrylic-acid 3-hydroxypropyl, (meth) acrylic acid 2-hydroxybutyl, (Meth) acrylic-acid hydroxyalkyl esters, such as 3-hydroxybutyl (meth) acrylic acid and 4-hydroxybutyl (meth) acrylic acid, etc. are mentioned.

Among these, from the viewpoint of the reactivity of the hydroxyl group in the (meth) acrylic acid ester copolymer (A) obtained, and the reactivity of the heat crosslinking agent (B), and another monomer, (meth) acrylic acid 2-hydroxyethyl and (meth) 1 or more types chosen from 4-hydroxybutyl acrylate are preferable, and 1 or more types chosen from 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferable. These may be used independently and may be used in combination of 2 or more type.

It is preferable that a (meth) acrylic acid ester copolymer (A) contains 3 mass% or more of hydroxyl-containing monomers as a monomer unit which comprises the said copolymer, It is more preferable to contain 10 mass% or more, 15 mass It is more preferable to contain more than%, and it is especially preferable to contain 18 mass% or more. Moreover, it is preferable that a (meth) acrylic acid ester copolymer (A) contains 50 mass% or less of hydroxyl-containing monomers as a monomer unit which comprises the said polymer, It is more preferable to contain 45 mass% or less, 40 It is more preferable to contain mass% or less.

When the (meth) acrylic acid ester copolymer (A) contains a hydroxyl group-containing monomer in the above range as the monomer unit, a good crosslinked structure is formed in the pressure-sensitive adhesive obtained, and a pressure-sensitive adhesive having a relatively high film strength is obtained. Excellent whitening. This is because a predetermined amount of hydroxyl groups remain in the pressure-sensitive adhesive.

When the hydroxyl group is a hydrophilic group and such a hydrophilic group is present in a predetermined amount of the pressure-sensitive adhesive, even when the pressure-sensitive adhesive is placed under high temperature and high humidity conditions, compatibility with moisture that has penetrated the pressure under the high temperature and high humidity conditions is good, and as a result, at room temperature and humidity The whitening of the adhesive at the time of return is suppressed.

As reactive group containing monomers other than a hydroxyl group containing monomer, the monomer (carboxy group containing monomer) which has a carboxy group in a molecule | numerator, the monomer (amino group containing monomer) which has an amino group in a molecule | numerator, etc. are mentioned. Among these, even if the weight average molecular weight of a (meth) acrylic acid ester copolymer (A) is comparatively low, a carboxyl group-containing monomer is preferable from a viewpoint that the desired cohesion force is exhibited.

As a carboxyl group-containing monomer, ethylenic unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, a citraconic acid, are mentioned, for example.

Among these, acrylic acid is preferable from the viewpoint of the reactivity of the carboxyl group in the obtained (meth) acrylic acid ester copolymer (A) with the heat crosslinking agent (B), and copolymerization with another monomer. These may be used independently and may be used in combination of 2 or more type.

When the (meth) acrylic acid ester copolymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the copolymer, the (meth) acrylic acid ester copolymer (A) is 5% by mass of the carboxyl group-containing monomer. It is preferable to contain more than, and it is more preferable to contain 10 mass% or more. Moreover, it is preferable that a (meth) acrylic acid ester copolymer (A) contains 30 mass% or less of monomers which comprise the said polymer, and it is more preferable to contain 15 mass% or less.

When the (meth) acrylic acid ester copolymer (A) contains a carboxyl group-containing monomer as a monomer unit in the said range, a favorable crosslinked structure is formed in the adhesive obtained, and the adhesive with a relatively high film strength is obtained.

Moreover, it is also preferable that a (meth) acrylic acid ester copolymer (A) contains a trace amount or does not contain a carboxyl group-containing monomer as a monomer unit which comprises the said copolymer. Since carboxyl group is an acid component, it does not contain a carboxyl group-containing monomer, and a problem arises with an acid to a sticking object of an adhesive, for example, transparent conductive films, such as tin dope indium oxide (ITO), and a metal Even when a film or the like is present, these problems due to acid (corrosion, resistance value change, etc.) can be suppressed.

However, it is acceptable to contain a predetermined amount of a carboxyl group-containing monomer so that the said problem does not arise. Specifically, in the (meth) acrylic acid ester copolymer (A), as the monomer unit, the carboxyl group-containing monomer is contained in an amount of less than 5% by mass, preferably 2% by mass or less, more preferably 0.1% by mass or less. Is allowed.

Examples of the amino group-containing monomers include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used independently and may be used in combination of 2 or more type.

(1.3.1.2. (Meth) acrylic acid alkyl ester)

It is preferable that the (meth) acrylic acid ester copolymer (A) contains the (meth) acrylic-acid alkylester whose carbon number of an alkyl group is 1-20 as a monomer unit which comprises the said copolymer. Thereby, an adhesive can express preferable adhesiveness. Moreover, it is preferable that the (meth) acrylic-acid alkylester whose carbon number of an alkyl group is 1-20 is a linear or branched structure from a viewpoint which can express more preferable adhesiveness.

Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate. N-pentyl acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, (meth) acrylic acid Myristyl, palmityl (meth) acrylate, stearyl (meth) acrylate, etc. are mentioned.

Among these, (meth) acrylic acid ester whose carbon number of an alkyl group is 1-8 from a viewpoint of improving adhesiveness further is preferable. Specifically, at least one selected from n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate is particularly preferable, and at least one selected from n-butyl acrylate and 2-ethylhexyl acrylate is particularly preferred. Do. In addition, these may be used independently and may be used in combination of 2 or more type.

(Meth) acrylic acid ester copolymer (A) is a monomer unit which comprises the said copolymer, It is preferable to contain 40 mass% or more of (meth) acrylic-acid alkylesters of 1-20 carbon atoms of an alkyl group, and 50 mass% It is more preferable to contain more, and it is still more preferable to contain 60 mass% or more. When 40 mass% or more of (meth) acrylic-acid alkylester is contained, preferable adhesiveness can be provided to the (meth) acrylic acid ester copolymer (A).

Moreover, it is preferable to contain 90 mass% or less of (meth) acrylic-acid alkylesters with 1-20 carbon atoms of an alkyl group, It is more preferable to contain 80 mass% or less, It is further more preferable to contain 70 mass% or less. By making content of a (meth) acrylic-acid alkylester into 90 mass% or less, the other monomer component for expressing a desired characteristic can be introduce | transduced in a (meth) acrylic acid ester copolymer (A) in a desired amount.

(1.3.1.3 monomer containing alicyclic structure)

It is preferable that the (meth) acrylic acid ester copolymer (A) contains the monomer (alicyclic structure containing monomer) which has an alicyclic structure in a molecule | numerator as a monomer unit which comprises the said copolymer. Since an alicyclic structure containing monomer is bulky, it exists in the copolymer, and it is estimated that the space | interval between polymers becomes wide. As a result, the adhesive obtained can be made excellent in flexibility. Therefore, when the (meth) acrylic acid ester polymer (A) contains an alicyclic structure containing monomer as a monomer unit, the adhesive obtained by crosslinking an adhesive composition is more excellent in an initial stage followability.

The carbon ring of the alicyclic structure in an alicyclic structure containing monomer may be a saturated structure, or may have a unsaturated bond in one part. In addition, the alicyclic structure may be a monocyclic alicyclic structure or may be a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. In the obtained (meth) acrylic acid ester copolymer (A), the alicyclic structure is polycyclic alicyclic structure (polycyclic structure) from the viewpoint of widening the interval between the polymers and effectively exhibiting the flexibility of the pressure-sensitive adhesive. desirable. Moreover, it is especially preferable that the said polycyclic structure is a 2 to 4 ring alicyclic structure from a compatible viewpoint of (meth) acrylic acid ester copolymer (A) and another component.

In addition, from the viewpoint of effectively exerting the flexibility of the pressure-sensitive adhesive in the same manner as described above, the carbon number of the alicyclic structure (all carbon number of the portion forming the ring, and when a plurality of rings are present independently, the carbon number of the sum It is preferable that it is normally 5 or more, and it is more preferable that it is 7 or more. On the other hand, the upper limit of the carbon number of the alicyclic structure is not particularly limited, but is preferably 15 or less, more preferably 10 or less from the viewpoint of compatibility as described above.

As an alicyclic structure, 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, cuvane skeleton, vasketein skeleton, Hausein skeleton, The structure containing a spiro skeleton etc. are mentioned.

Among them, from the viewpoint of obtaining more excellent durability, dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), adamantane skeleton (carbon number of alicyclic structure: 10) and isobornyl skeleton (carbon number of alicyclic structure) The structure containing 1 or more types chosen from: 7) is preferable, and the structure containing an isobornyl skeleton is more preferable.

Therefore, as said alicyclic structure containing monomer, the (meth) acrylic acid ester monomer containing said skeleton is preferable. Specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclo (meth) acrylate Pentenyloxyethyl etc. are mentioned.

Among these, 1 or more types selected from dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, and isobornyl (meth) acrylate are preferable from a viewpoint of obtaining more durable, and isoboryl (meth) acrylate. 1 or more types chosen from nil are more preferable, and isobornyl acrylate is especially preferable. These may be used individually by 1 type and may be used in combination of 2 or more type.

As a monomer unit which a (meth) acrylic acid ester copolymer (A) comprises the said copolymer, it is preferable to contain 1 mass% or more of alicyclic structure containing monomers, It is more preferable to contain 4 mass% or more, 8 It is more preferable to contain mass% or more. Moreover, it is preferable to contain 40 mass% or less of alicyclic structure containing monomers, and, as for the (meth) acrylic acid ester copolymer (A) as a monomer unit which comprises the said copolymer, it is more preferable to contain 25 mass% or less It is more preferable to contain 15 mass% or less. When content of an alicyclic structure containing monomer exists in said range, the softness | flexibility of the adhesive obtained becomes favorable and it becomes the thing excellent in the initial stage trackability.

(1.3.1.4.Nitrogen atom-containing monomers)

It is preferable that the (meth) acrylic acid ester copolymer (A) contains the monomer (nitrogen atom containing monomer) which has a nitrogen atom in a molecule | numerator as a monomer unit which comprises the said copolymer. In addition, the amino group containing monomer illustrated as a reactive group containing monomer is removed from the said nitrogen atom containing monomer. By providing a nitrogen atom containing monomer in a copolymer as a structural unit, reaction of an acrylate ester copolymer (A) and a thermal crosslinking agent (B) can be accelerated | stimulated, polarity can be provided to an adhesive, and cohesion force of an adhesive itself can be improved. .

As said nitrogen atom containing monomer, the monomer which has a tertiary amino group, the monomer which has an amide group, the monomer which has a nitrogen containing heterocyclic ring, etc. are mentioned. Among these, the monomer which has a nitrogen containing heterocyclic ring is preferable.

As a monomer which has a nitrogen-containing heterocyclic ring, N- (meth) acryloyl morpholine, N-vinyl-2-pyrrolidone, N- (meth) acryloyl pyrrolidone, N- (meth ) Acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloylaziridine, aziridinylethyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine, 2 -Vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. are mentioned.

Among these, N- (meth) acryloyl morpholine is preferable and N-acryloyl morpholine is more preferable from a viewpoint of obtaining more adhesive force.

As nitrogen atom containing monomers other than the monomer which has a nitrogen containing heterocyclic ring mentioned above, it is (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N-, for example. tert-butyl (meth) 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-vinyl caprolactam, dimethylaminoethyl (meth) acrylate, etc. are mentioned.

Said nitrogen atom containing monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that a (meth) acrylic acid ester copolymer (A) contains 1 mass% or more of nitrogen atom containing monomers as a monomer unit which comprises the said copolymer, It is more preferable that it contains 4 mass% or more, 8 mass% It is more preferable to contain more. Moreover, it is preferable that a (meth) acrylic acid ester copolymer (A) contains 40 mass% or less of nitrogen atom containing monomers as a monomer unit which comprises the said copolymer, It is more preferable to contain 25 mass% or less, It is more preferable to contain 15 mass% or less. When content of a nitrogen atom containing monomer exists in said range, the cohesion force of the adhesive obtained is improved effectively.

(1.3.1.5.Other)

The (meth) acrylic acid ester copolymer (A) may contain another monomer as needed as a monomer unit which comprises the said copolymer. As another monomer, the monomer which does not contain the reactive functional group is preferable. As such another monomer, (meth) acrylic-acid alkoxy alkyl esters, such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, vinyl acetate, styrene, etc. are mentioned, for example. These may be used independently and may be used in combination of 2 or more type.

The polymerization aspect of the (meth) acrylic acid ester copolymer (A) may be a random copolymer or a block copolymer.

It is preferable that the weight average molecular weight of a (meth) acrylic acid ester polymer (A) is 100,000 or more as a lower limit, It is especially preferable that it is 250,000 or more, Furthermore, it is preferable that it is 400,000 or more. When the lower limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is the above, the film strength of the pressure-sensitive adhesive obtained is higher. Moreover, it is preferable that the weight average molecular weight of a (meth) acrylic acid ester polymer (A) is 900,000 or less as an upper limit, It is preferable that it is especially 750,000 or less, Furthermore, it is preferable that it is 600,000 or less. If the upper limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is below the above, the level | step difference followability of the adhesive obtained is more excellent. In addition, the weight average molecular weight in this specification is a value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

In addition, in an adhesive composition, (meth) acrylic acid ester copolymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

(1.3.2.Heat crosslinking)

When the adhesive composition containing the heat crosslinking agent (B) is heated, the heat crosslinking agent (B) crosslinks with the (meth) acrylic acid ester copolymer (A) to form a crosslinked structure (three-dimensional network structure). Thereby, the adhesive with comparatively high film strength is obtained.

As said thermal crosslinking agent (B), what is necessary is just to react with the reactive group which the (meth) acrylic acid ester copolymer (A) has. For example, isocyanate crosslinking agent, epoxy crosslinking agent, amine crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent And ammonium salt-based crosslinking agents.

What is necessary is just to select these according to the reactivity of the reactive group which the (meth) acrylic acid ester copolymer (A) has. For example, when the reactive group which the (meth) acrylic acid ester copolymer (A) has is a hydroxyl group, it is preferable to use an isocyanate type crosslinking agent excellent in the reactivity with a hydroxyl group. When the reactive group which the (meth) acrylic acid ester copolymer (A) has is a carboxy group, it is preferable to use the epoxy type crosslinking agent excellent in the reactivity with a carboxy group. In addition, a thermal crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more type.

Isocyanate type crosslinking agent contains a polyisocyanate compound at least. As a polyisocyanate compound, For example, Aromatic polyisocyanate, such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate; Aliphatic polyisocyanates such as hexamethylene diisocyanate; Alicyclic polyisocyanate, such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, etc. are mentioned. Moreover, the adduct bodies etc. which are reactants of these biuret bodies, isocyanurate bodies, and also low molecular weight active hydrogen containing compounds, such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylol propane, castor oil, etc. are mentioned. Can be.

Among these, trimethylolpropane-modified aromatic polyisocyanate is preferable from a viewpoint of reactivity with a hydroxyl group, and especially 1 or more types chosen from trimethylolpropane modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are preferable.

As an epoxy type crosslinking agent, it is 1, 3-bis (N, N- diglycidyl aminomethyl) cyclohexane, N, N, N ', N'- tetraglycidyl-m-xylylenediamine, for example. , Ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidylamine and the like. Among these, 1,3-bis (N, N- diglycidylaminomethyl) cyclohexane is preferable from the viewpoint of reactivity with the carboxyl group.

It is preferable that content of the thermal crosslinking agent (B) in an adhesive composition is 0.01 mass part or more with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A), It is more preferable that it is 0.05 mass part or more, 0.1 mass part It is more preferable that it is above. When the lower limit of content of a thermal crosslinking agent (B) is said value, the adhesive obtained can exhibit favorable cohesion force and the adhesive with a comparatively high film strength is obtained. Moreover, it is preferable that the said content is 10 mass parts or less, It is more preferable that it is 5 mass parts or less, It is further more preferable that it is 0.4 mass parts or less. When the upper limit of content of a thermal crosslinking agent (B) is said value, the adhesive obtained will have sufficient flexibility, and the adhesive excellent in the initial stage followability is obtained.

(1.3.3. Active energy ray curable components)

The adhesive obtained by thermally crosslinking an adhesive composition contains the uncured active energy ray curable component (C). Therefore, the adhesive which concerns on this embodiment is an active energy ray curable adhesive. When an active energy ray is irradiated after this adhesive adheres to a to-be-adhered body, superposition | polymerization of an active-energy-ray-curable component (C) is accelerated by the cleavage of photoinitiator (D) mentioned later. The polymerized active energy ray curable component (C) is estimated to stick to the crosslinked structure (three-dimensional network structure) formed by thermal crosslinking of the (meth) acrylic acid ester copolymer (A) and the thermal crosslinking agent (B). The pressure-sensitive adhesive having such a higher order structure is excellent in step tracking and blister resistance under high temperature and high humidity conditions.

The active energy ray curable component (C) is not particularly limited as long as it is a component which is cured by irradiation of an active energy ray in the presence of a photopolymerization initiator (D) to be described later and the above effects are obtained. Any of a monomer, an oligomer, or a polymer may be sufficient, and their mixture may be sufficient. Among these, the polyfunctional acrylate monomer of less than 1,000 molecular weight which is excellent in compatibility with (meth) acrylic acid ester copolymer (A) etc. is preferable.

As a polyfunctional acrylate monomer of less than 1000 molecular weight, a bifunctional, trifunctional, tetrafunctional, 5-functional, and 6-functional acrylate monomer is preferable. As a bifunctional acrylate type monomer, 1, 4- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene, for example Glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxy pivalate neopentyl glycol di (meth) acrylate, dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopente Nyldi (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, ethoxylated bisphenol A diacrylate, 9, 9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene etc. are mentioned.

As a trifunctional acrylate-type monomer, a trimethylol propane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tree (meth ) Acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, ε-caprolactone modified tris- (2- (meth) acryloxyethyl) isocyanurate, etc. Can be mentioned.

Diglycerol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. are mentioned as a tetrafunctional acrylate-type monomer. A propionic acid modified dipentaerythritol penta (meth) acrylate etc. are mentioned as a 5-functional acrylate-type monomer. Examples of the difunctional acrylate monomer include dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like.

Among these, di (acryloxyethyl) isocyanurate, tris (acryloxyethyl) isocyanurate, and (epsilon) -caprolactone modified tris- (in terms of step tracking and blister resistance under high temperature and high humidity conditions of the resulting pressure-sensitive adhesive) Polyfunctional acrylate monomers containing an isocyanurate structure in a molecule such as 2- (meth) acryloxyethyl) isocyanurate are preferable. Among these, the polyfunctional acrylate monomer which contains an isocyanurate structure more than trifunctional type and a molecule | numerator is more preferable. Specifically, ε-caprolactone modified tris- (2- (meth) acryloxyethyl) isocyanurate is particularly preferable. These may be used individually by 1 type and may be used in combination of 2 or more type.

As an active energy ray curable component (C), you may use an active energy ray hardening-type acrylate oligomer. Examples of such acrylate oligomers include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, and silicone acrylates.

It is preferable that it is 50,000 or less, as for the weight average molecular weight of said acrylate oligomer, it is more preferable that it is 500-50,000, and it is still more preferable that it is 3,000-40,000. These acrylate oligomers may be used individually by 1 type, or may be used in combination of 2 or more type.

Moreover, as an active energy ray curable component (C), the adduct acrylate polymer in which the group which has a (meth) acryloyl group was introduce | transduced into the side chain can also be used. Such adduct acrylate polymer is a (meth) acryloyl group and a part of the crosslinkable functional groups of the said copolymer, using the copolymer of (meth) acrylic acid ester and the monomer which has a crosslinkable functional group in a molecule | numerator. It can obtain by making the compound which has group which react with a crosslinkable functional group react.

It is preferable that it is about 50,000-900,000, and, as for the weight average molecular weight of said adduct acrylate polymer, it is more preferable that it is about 100,000-500,000.

As an active energy ray curable component (C), although the above-mentioned polyfunctional acrylate monomer is preferable, you may select and use 1 type from a polyfunctional acrylate monomer, an acrylate oligomer, and an adduct acrylate polymer. , May be used in combination of 2 or more type, and may be used in combination with these components and another active energy ray curable component.

Content of the active energy ray curable component (C) in an adhesive composition is a (meth) acrylic acid ester copolymer (A) 100 from a viewpoint which can make ratio of the gel fraction of the adhesive mentioned above and ratio of storage elastic modulus preferable. It is preferable that it is 1 mass part or more with respect to mass part, It is more preferable that it is 2 mass parts or more, It is further more preferable that it is 4 mass parts or more. Thereby, it can be made more excellent in the step | follower followable | trackability and blister resistance under the high temperature, high humidity conditions of the adhesive obtained. On the other hand, when the said content is too large, the crosslinking of the adhesive after active energy ray hardening will become too dense, adhesive force falls, and it exists in the tendency for a blister resistance to deteriorate and durability to worsen. From this viewpoint, it is preferable that the upper limit of content of an active energy ray curable component (C) is 30 mass parts or less, It is more preferable that it is 15 mass parts or less, It is further more preferable that it is 10 mass parts or less.

(1.3.4.Photopolymerization Initiator)

In this embodiment, as a photoinitiator (D), the photoinitiator whose absorbance of wavelength 380nm in acetonitrile solution of 0.1 mass% of concentration is 1.0 or more is used. That is, since the light absorption of a photoinitiator (D) generate | occur | produces also in the comparatively long wavelength side, even if the ultraviolet absorber (E) mentioned later is contained in the adhesive which concerns on this embodiment, than the wavelength of the light which the said ultraviolet absorber (E) absorbs The energy of light having a long wavelength can be used to polymerize the adhesive sufficiently or to be a post-curing adhesive having ultraviolet absorbing ability.

Moreover, it is preferable that it is 1.1 or more, and, as for the absorbance of wavelength 380nm of a photoinitiator (D), it is more preferable that it is 1.3 or more. Although the upper limit of the said absorbance is not specifically limited, Usually, it is preferable that it is 2.5 or less, and it is more preferable that it is 2.0 or less. When absorbance is too big | large, the hardening reaction of the active energy ray curable component (C) by a photoinitiator (D) may advance with environmental light, such as a fluorescent lamp, at the time of direct bonding film formation or storage. In addition, what is necessary is just to measure the absorbance of a photoinitiator (D) by the method shown to the Example mentioned later.

Moreover, in a photoinitiator (D), it is preferable that the absorption maximum wavelength of the absorbance of wavelength 200-500 nm in the acetonitrile solution of density | concentration 0.1 mass% exists in 350 nm or more, and it is more in 370 nm or more. It is preferable and it is more preferable to exist in 380 nm or more. In addition, when two or more absorption maximum wavelengths of the absorbance of wavelength 200-500 nm exist, at least 1 absorption maximum wavelength should just be in the said range.

When absorption maximum wavelength exists in the said range, the energy of the grade which can fully photopolymerize the adhesive which concerns on this embodiment can be supplied to an adhesive. As a result, it is possible to obtain a post-curing pressure-sensitive adhesive which is more excellent in step tracking and blister resistance while having ultraviolet absorbing ability.

On the other hand, the upper limit of the absorption maximum wavelength is not particularly limited, but in the same manner as the absorbance, it is preferably 450 nm or less, more preferably 410 nm or less, from the viewpoint of preventing the progress of the polymerization reaction caused by ambient light. It is more preferable that it is nm or less.

As such a photoinitiator (D), 2,4,6-trimethylbenzoyl-diphenyl- phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide etc. are mentioned, for example. have. These may be used independently and may be used in combination of 2 or more type.

It is preferable that it is 0.1 mass part or more with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A), and, as for content of the photoinitiator (D) in an adhesive composition, it is more preferable that it is 0.3 mass parts or more. Since the lower limit of content of a photoinitiator (D) is the said, even if it contains the ultraviolet absorber in an adhesive, when an active energy ray is irradiated, a photoinitiator (D) will become easy to be cleaved, and this is an active energy Polymerization of a precurable component (C) is accelerated | stimulated and the adhesive after hardening fully obtained can be obtained.

Moreover, it is preferable that it is 3.0 mass parts or less with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A), and, as for content of a photoinitiator (D), it is more preferable that it is 1.0 mass part or less. When there is too much content of a photoinitiator (D), a photoinitiator will remain in an adhesive after hardening easily, and foam | bubble etc. generate | occur | produce, for example by volatilization of the photoinitiator which remained under high temperature, high humidity conditions, for example. It is easy to lead to the deterioration of the step followingability and the deterioration of blister resistance under high temperature and high humidity conditions. Therefore, when the upper limit of content of a photoinitiator (D) is said value, the adhesive which has the outstanding level | step difference followability and blister resistance can be obtained.

Moreover, it is preferable that it is 1 mass part or more with respect to 100 mass parts of active energy ray curable components (C), and, as for content of the photoinitiator (D) in an adhesive composition, it is more preferable that it is 5 mass parts or more. Since the lower limit of content of a photoinitiator (D) is the said, even if it contains the ultraviolet absorber in an adhesive, when an active energy ray is irradiated, a photoinitiator (D) will become easy to be cleaved, and this is an active energy Polymerization of a precurable component (C) is accelerated | stimulated and the adhesive after hardening fully obtained can be obtained.

Moreover, it is preferable that it is 30 mass parts or less with respect to 100 mass parts of active energy ray curable components (C), and, as for content of a photoinitiator (D), it is more preferable that it is 15 mass parts or less. When the upper limit of content of a photoinitiator (D) is said value, before hardening, since the advancing of the polymerization reaction resulting from environmental light can be prevented, the adhesive excellent in the initial stage followability can be obtained. Moreover, after hardening, since a photoinitiator does not remain | survives well in the adhesive after hardening, it is excellent in the level | step difference followability and blister resistance under high temperature, high humidity conditions.

(1.3.5.UV absorbers)

An adhesive composition contains a ultraviolet absorber (E). As mentioned above, even if the adhesive obtained by heat-crosslinking an adhesive composition contains a ultraviolet absorber (E), the adhesive hardened | cured fully can be obtained by making a photoinitiator (D) into said thing. As a result, although the sclerosis | hardenability of the adhesive after hardening which an adhesive hardens | cures is favorable, for example, even if the material of the protective panel of a display body consists of glass which permeate | transmits an ultraviolet-ray, the said post-curing adhesive can absorb an ultraviolet-ray. have. Therefore, deterioration of the member which comprises a display body can be suppressed.

As a ultraviolet absorber (E), a benzophenone type ultraviolet absorber, a benzotriazole type ultraviolet absorber, a triazine type ultraviolet absorber, a salicylic acid type ultraviolet absorber, an oxalic acid anhydride type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, etc. are mentioned, for example. have. These ultraviolet absorbers can be used individually by 1 type or in combination of 2 or more type.

As a benzophenone type ultraviolet absorber, 2, 4- dihydroxy benzophenone, 2-hydroxy-4- methoxy benzophenone, 2-hydroxy-4- octoxy benzophenone, 2-hydroxy, for example. 4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydrate benzophenone, 2,2 ' -Dihydroxy-4-methoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 '-Dihydroxy-4,4'-dimethoxy-5-sodium sulfoxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2-hydroxy-4-n- Dodecyloxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, and the like.

As a benzotriazole type ultraviolet absorber, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- ( 2-hydroxy-3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylene Bis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-tert- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-di-tert- Amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2- Hydroxy-4-octoxyphenyl) benzotriazole, 2,2'-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis (1,3-benzojade Photo-4-one, 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimideme ) -5-methylphenyl] benzotriazole, and the like.

As a triazine ultraviolet absorber, 2- (2-hydroxy-4- methoxyphenyl) -4,6-diphenyl- 1,3,5-triazine, 2- (2-hydroxy-, for example 4-ethoxyphenyl) -4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-propoxyphenyl) -4,6-diphenyl-1,3,5 -Triazine, 2- (2-hydroxy-4-butoxyphenyl) -4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-hexyloxyphenyl)- 4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-octyloxyphenyl) -4,6-diphenyl-1,3,5-triazine, 2- ( 2-hydroxy-4-dodecyloxyphenyl) -4,6-diphenyl-1,3,5-triazine, 2- (2-hydroxy-4-benzyloxyphenyl) -4,6-diphenyl -1,3,5-triazine, 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3-5-triazine, 2 To 4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine, 2- (2-hydroxy-4- [1-octyloxycarbonyl Methoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3-dodecyl Cipropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3- Tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy- 3- (2'-ethyl) hexyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2 , 4-dimethylphenyl) -6- [2-hydroxy-4- (3-octyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine, 2,4-bis ( 2,4-dimethylphenyl) -6- [2-hydroxy-4- (3-nonyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (3-decyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine, 2- ( 2-hydroxy-4-acryloyloxyethoxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine etc. are mentioned.

As a salicylic acid type ultraviolet absorber, a phenyl salicylate, p-tert- butylphenyl salicylate, p-octylphenyl salicylate, etc. are mentioned, for example.

As a cyanoacrylate type ultraviolet absorber, 2-ethylhexyl-2-cyano-3,3'- diphenyl acrylate, ethyl-2-cyano-3,3'- diphenyl acrylate, for example Etc. can be mentioned.

Among these, at least one selected from a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and a triazine ultraviolet absorber is preferable, and at least one selected from a benzophenone ultraviolet absorber and a benzotriazole ultraviolet absorber is more preferable. desirable.

It is preferable that content of a ultraviolet absorber (E) is 1 mass part or more with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A), It is more preferable that it is 2 mass parts or more, It is further more preferable that it is 4 mass parts or more. . Moreover, it is preferable that content of a ultraviolet absorber (E) is 25 mass parts or less, It is more preferable that it is 15 mass parts or less, It is further more preferable that it is 8 mass parts or less. When there is too little content of a ultraviolet absorber (E), absorption of an ultraviolet-ray will become inadequate and there exists a tendency which cannot suppress deterioration of the member which comprises a display body. On the other hand, when there is too much content of an ultraviolet absorber (E), the light used for hardening of an adhesive will also be absorbed to some extent, and there exists a tendency for hardening of the said adhesive to be insufficient, and the step | following followability and blister resistance under high temperature, high humidity conditions are sufficient. This gets worse.

Moreover, it is preferable that content of an ultraviolet absorber (E) is 1 mass part or more with respect to 1 mass part of photoinitiators (D), It is more preferable that it is 5 mass parts or more, It is further more preferable that it is 8 mass parts or more.

Moreover, it is preferable that it is 50 mass parts or less with respect to 1 mass part of photoinitiators (D), It is more preferable that it is 30 mass parts or less, It is further more preferable that it is 15 mass parts or less. When content of the ultraviolet absorber (E) with respect to a photoinitiator (D) is in the said range, while the absorptivity of an ultraviolet-ray is sufficient, the adhesive which can fully open | cure a photoinitiator and can harden | cure can be obtained. As a result, the adhesive after hardening can suppress deterioration of the member which comprises a display body.

(1.3.6.Silane coupling agent)

It is preferable that an adhesive composition contains a silane coupling agent (F) further. Thereby, when a glass member is contained in a to-be-adhered body, adhesiveness of an adhesive and a post-hardening adhesive and the said glass member improves. Moreover, even when a plastic member is contained in a to-be-adhered body, the adhesiveness of an adhesive and a post-curing adhesive and a plastic plate improves. Therefore, the pressure-sensitive adhesive containing the silane coupling agent (F) and the pressure-sensitive adhesive after curing become more excellent in step followability under high temperature and high humidity conditions.

In this embodiment, as an silane coupling agent (F), it is preferable to have light transmittance as an organosilicon compound which has at least 1 alkoxysilyl group in a molecule | numerator.

As such a silane coupling agent (F), For example, polymeric unsaturated-group containing silicon compounds, such as vinyl trimethoxysilane, vinyl triethoxysilane, and methacryloxypropyl trimethoxysilane; Silicon compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; Mercapto group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane; Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane ; 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of them, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. And condensates of alkyl group-containing silicon compounds. These may be used individually by 1 type and may be used in combination of 2 or more type.

It is preferable that content of a silane coupling agent (F) is 0.05 mass part or more with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A), It is more preferable that it is 0.1 mass part or more, It is further more preferable that it is 0.2 mass part or more. Do. Moreover, it is preferable that the said content is 3 mass parts or less, It is more preferable that it is 1 mass part or less, It is further more preferable that it is 0.5 mass part or less.

(1.3.7.Other additives)

The adhesive which concerns on this embodiment may contain various additives as needed. As such an additive, an antistatic agent, a tackifier, antioxidant, a light stabilizer, a softener, a filler, a refractive index regulator, etc. are illustrated, for example.

(1.3.8. Preparation of Adhesive Composition)

An adhesive composition manufactures a (meth) acrylic acid ester copolymer (A), and heat-crosslinks (B), an active energy ray curable component (C), and photopolymerization to the solution of the obtained (meth) acrylic acid ester copolymer (A). It can manufacture by adding an initiator (D) and a ultraviolet absorber (E), and fully mixing. You may add a silane coupling agent (F), an additive, etc. as needed. What is necessary is just to manufacture a (meth) acrylic acid ester copolymer (A) as follows.

A (meth) acrylic acid ester copolymer (A) can be manufactured by superposing | polymerizing the mixture of the monomer which comprises a polymer by a normal radical polymerization method. The polymerization of the (meth) acrylic acid ester copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as desired. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use two or more types together.

As a polymerization initiator, an azo compound, an organic peroxide, etc. are mentioned, You may use two or more types together. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane 1-). Carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl2,2 ' -Azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2 ' -Azobis [2- (2-imidazolin-2-yl) propane] etc. are mentioned.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di (2-ethoxyethyl) peroxydi Carbonate, t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

Moreover, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercaptoethanol.

(1.3.9. Preparation of Adhesive)

An adhesive is obtained by heat-crosslinking the (meth) acrylic acid ester copolymer (A) in an adhesive composition with a heat crosslinking agent (B). That is, heat crosslinking of an adhesive composition is performed by heat processing. In addition, this heat processing can also serve as the drying process after application | coating of an adhesive composition.

It is preferable that it is 50-150 degreeC, and, as for the heating temperature of heat processing, it is more preferable that it is 70-120 degreeC. Moreover, it is preferable that they are 10 second-10 minutes, and, as for heating time, it is more preferable that they are 50 second-2 minutes. Moreover, it is especially preferable to form the curing period of about 1 to 2 weeks at normal temperature (for example, 23 degreeC, 50% RH) after heat processing.

By the above heat treatment (and curing), the (meth) acrylic acid ester copolymer (A) is preferably crosslinked via the heat crosslinking agent (B) to form a crosslinked structure. Through such a process, the adhesive which concerns on this embodiment is obtained.

In addition, content and a property of the other components (active energy ray curable component (C), photoinitiator (D), ultraviolet absorber (E), etc.) contained in an adhesive composition do not change before and after thermal crosslinking.

(1.4. Peeling Sheet)

The peeling sheets 12a and 12b protect the adhesive layer 11 until the use of the direct bonding film 1, and are peeled off when the direct bonding film 1 (adhesive layer 11) is used. In the direct bonding film 1 which concerns on this embodiment, one or both of the peeling sheets 12a and 12b is not necessarily required.

As the release sheets 12a and 12b, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene Naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, ethylene (meth) acrylic acid ester copolymer film, polystyrene film, poly Carbonate film, a polyimide film, a fluororesin film, etc. are used. Moreover, these crosslinked films are also used. Moreover, these laminated | multilayer film may be sufficient.

It is preferable that the peeling process is given to the peeling surface (especially the surface which contact | connects the adhesive layer 11) of the said peeling sheets 12a and 12b. As a peeling agent used for a peeling process, alkyd type, silicone type, fluorine type, unsaturated polyester type, polyolefin type, wax type peeling agent is mentioned, for example.

Moreover, it is preferable to make one peeling sheet into the heavy peeling type peeling sheet with a large peeling force, and to make the other peeling sheet a light peeling type peeling sheet with small peeling force among peeling sheets 12a and 12b.

Although there is no restriction | limiting in particular about the thickness of release sheet 12a, 12b, Usually, they are 20 micrometers or more and 200 micrometers or less.

(2.Manufacture of direct bonding film)

It does not restrict | limit especially as a method of manufacturing the direct bonding film 1, What is necessary is just to manufacture by a well-known method. For example, an application layer having a predetermined thickness is applied to a release surface of one release sheet 12a (or 12b) by applying the coating liquid of the above adhesive composition, and performing heat treatment to heat crosslink the adhesive composition. Form. The peeling surface of the other peeling sheet 12b (or 12a) is superimposed on the formed application layer. When a curing period is required, the coating layer becomes the pressure-sensitive adhesive layer 11 by curing. When a curing period is not necessary, the said application layer becomes the adhesive layer 11. Thereby, the said direct bonding film 1 is obtained.

As another example of manufacture of the direct bonding film 1, the coating liquid of said adhesive composition is apply | coated to the peeling surface of one peeling sheet 12a, heat-processes, heat-crosslinks an adhesive composition, and an application layer To form a release sheet 12a with a coating layer. Moreover, the coating liquid of said adhesive composition is apply | coated to the peeling surface of the other peeling sheet 12b, it heat-processes, heat-crosslinks the adhesive composition, and forms a coating layer, and the peeling sheet with a coating layer 12b To get. And the peeling sheet 12a with a coating layer and the peeling sheet 12b with a coating layer are bonded together so that both coating layers may contact each other. When a curing period is required, curing is performed, whereby the laminated coating layer becomes the pressure-sensitive adhesive layer 11. When the curing period is not necessary, the laminated coating layer is the pressure-sensitive adhesive layer (11). Thereby, the said direct bonding film 1 is obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it becomes possible to manufacture stably.

As a method of apply | coating the coating liquid of an adhesive composition, the bar coat method, the knife coat method, the roll coat method, the blade coat method, the die coat method, the gravure coat method etc. are illustrated, for example.

In the direct bonding film 1 which concerns on this embodiment, since the adhesive layer 11 has a crosslinked structure, the film strength of the adhesive layer 11 is comparatively high. As a result, when cutting the direct bonding film 1 or the like, it is suppressed that problems such as an adhesive stick out from the cut surface and the adhesive adheres to the blade. Moreover, also when the direct bonding film 1 is stored, it is suppressed that an adhesive leaks out from the adhesive layer 11 is suppressed.

(3. Use of direct bonding film)

The direct bonding film 1 which concerns on this embodiment is used as follows. First, the adhesive layer 11 of the direct bonding film 1 is bonded to a 1st display body structural member and a 2nd display body structural member. Subsequently, a predetermined active energy ray is irradiated to the pressure-sensitive adhesive layer 11 via the first display member or the second display member, and the pressure-sensitive adhesive layer 11 is cured to cure the pressure-sensitive adhesive layer (to be described later). In FIG. 2, it is set as the adhesive layer 11 'after hardening.

Before irradiation of an active energy ray, in this embodiment, since the adhesive which comprises the adhesive layer 11 contains both a crosslinked structure and an uncured active energy ray curable component, it is an adhesive, having predetermined cohesion force. The layer is relatively soft. Therefore, when the direct bonding film 1 is affixed on the display structure structural member which has a level | step difference, the adhesive layer 11 fully follows a level | step difference, and generation | occurrence | production of a clearance gap, a lift, etc. in the vicinity of a level | step difference is suppressed.

And after bonding an adhesive layer to a display body structural member in a comparatively soft state, predetermined | prescribed active energy ray is irradiated to an adhesive layer, and an adhesive layer is hardened. At this time, even if the pressure-sensitive adhesive layer contains an ultraviolet absorber, the wavelength at which the photopolymerization initiator can be cleaved is relatively long, so that the photopolymerization initiator is sufficiently cleaved and curing is sufficiently promoted. As a result, the cohesion force of the adhesive layer after hardening can be improved in the state which has the step | step traceability, while having ultraviolet absorbing ability. Therefore, the blister resistance becomes good.

In particular, even when the obtained laminated body (display) is placed for 72 hours under high temperature and high humidity conditions, for example, at 85 ° C. and 85% RH, generation of bubbles, lifting, peeling, etc. in the vicinity of the step is suppressed. Moreover, generation | occurrence | production of blisters, such as a bubble, a float, and peeling in the interface of a display body structural member and an adhesive layer after hardening, is also suppressed. That is, the direct bonding film 1 which concerns on this embodiment is excellent in not only the step difference tracking property of an initial stage, but also the step | following followability and blister resistance under high temperature, high humidity conditions, while having ultraviolet absorbing ability.

(4.indicator)

As shown in FIG. 2, the display body 2 which concerns on this embodiment is located between the 1st display body structural member 21 and the 2nd display body structural member 22 which have a level | step difference, and It has the post-hardening adhesive layer 11 'which bonds the 1st display body structural member 21 and the 2nd display body structural member 22 to each other. The adhesive layer 11 'after hardening is a hardened | cured material which hardened the adhesive layer 11 shown in FIG. 1 by active energy ray irradiation, and is bonded along the level | step difference of the 1st display member 21. This step is caused by the thickness of the printing layer 3 formed in the first display member 21.

(4.1.Adhesive layer after curing)

The adhesive layer 11 'after hardening hardens the adhesive layer 11 which the said direct bonding film 1 has by active energy ray irradiation. In this embodiment, this adhesive layer 11 'after hardening has a crosslinked structure which consists of a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B), and is active energy ray curable component (C) It consists of an adhesive which contains the structure (polymerization structure) hardened | cured by superposition | polymerization, the photoinitiator (D), and a ultraviolet absorber (E). It is assumed that the polymerization structure is stuck to a crosslinked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B). By having a structure in which a plurality of three-dimensional structures are entangled with each other, the pressure-sensitive adhesive layer after curing has high cohesion. Therefore, not only the normal blister resistance but also the blister resistance under high temperature, high humidity conditions are favorable.

Moreover, as long as the effect of this invention is acquired, the photoinitiator (D) which is not cleaved also by active energy ray irradiation may be contained in the post-curing adhesive which comprises the said post-curing adhesive layer 11 '. In this embodiment, in the adhesive after hardening, it is preferable that it is 0.1 mass% or less, and, as for the remainder of a photoinitiator, it is more preferable that it is 0.01 mass% or less.

(4.2. Other configurations of the indicator)

As the display body 2, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescent (organic EL) display, an electronic paper, etc. are mentioned, for example, A touch panel may be sufficient. Moreover, as the display body 2, the member which comprises one part of them may be sufficient.

It is preferable that the 1st display member 21 is a protective panel which consists of laminated bodies etc. which contain them other than a glass plate, a plastic plate, etc. In this case, it is common that the printing layer 3 is formed in frame shape on the adhesive layer 11 'side after hardening in the 1st display body structural member 21.

As mentioned above, in this embodiment, even if the protective panel as the 1st display body structural member 21 is comprised by the glass plate in the display body 2, the adhesive layer 11 'after hardening absorbs an ultraviolet-ray. Because of this, deterioration of the other display member can be suppressed. Moreover, in the display body 2, even if the protective panel as the 1st display body structural member 21 is comprised by the plastic board, the adhesive layer 11 'after hardening has the outstanding blister resistance. In the case where the protective panel is made of a plastic plate, the plastic plate easily permeates moisture in the air, and therefore, when placed under high temperature and high humidity conditions, for example, moisture easily enters the adhesive. As a result, when returning to normal temperature and humidity, whitening of an adhesive tends to arise due to the invasive water | moisture content. Even in such a case, when the hydroxyl group-containing monomer is included as the reactive group-containing monomer constituting the (meth) acrylic acid ester copolymer (A), the pressure-sensitive adhesive according to the present embodiment has good compatibility with invasive water. As a result, the whitening of the adhesive at the time of returning to normal temperature and humidity is suppressed, and it is excellent in moisture-heat-whitening resistance.

It does not specifically limit as said glass plate, For example, chemically strengthened glass, an alkali free glass, quartz glass, soda-lime glass, barium strontium containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass Etc. can be mentioned. Although the thickness of a glass plate is not specifically limited, Usually, it is 0.1 mm or more, Preferably it is 0.2 mm or more. Moreover, the said thickness is 5 mm or less normally, Preferably it is 2 mm or less.

It does not specifically limit as said plastic board, For example, an acryl board, a polycarbonate board, etc. are mentioned. Although the thickness of a plastic plate is not specifically limited, Usually, it is 0.2 mm or more, Preferably it is 0.4 mm or more. Moreover, the said thickness is 5 mm or less normally, Preferably it is 3 mm or less.

In addition, various functional layers (transparent conductive film, a metal layer, a silica layer, a hard coat layer, an antiglare layer, etc.) may be formed in the single side | surface or both surfaces of said glass plate and a plastic plate, and the optical member may be laminated | stacked. In addition, the transparent conductive film and the metal layer may be patterned.

The second display member 22 is an optical member to be attached to the first display member 21, a display module (e.g., a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electrophoresis). It is preferable that it is a laminated body containing a luminescence (organic EL) module, an optical member as a part of a display module, or a display module.

As said optical member, a scattering prevention film, a polarizing plate (polarizing film), a polarizer, a retardation plate (retardation film), a viewing angle compensation film, a brightness improving film, a contrast improving film, a liquid crystal polymer film, a diffusion film, semi-transmission A reflective film, a transparent conductive film, etc. are mentioned. As a scattering prevention film, the hard coat film etc. which a hard coat layer is formed in the single side | surface of a base film are illustrated.

The material which comprises the printing layer 3 is not specifically limited, The well-known material for printing is used. The thickness of the printing layer 3, that is, the height of the step is preferably 3 µm or more, preferably 5 µm or more, more preferably 7 µm or more, still more preferably 10 µm or more, and particularly preferably 20 µm or more. . Moreover, it is preferable that it is 50 micrometers or less, and, as for the said height, it is more preferable that it is 35 micrometers or less.

(4.4. Preparation of Indicator)

An example of the method of manufacturing the said display body 2 is shown. First, one peeling sheet 12a of the direct bonding film 1 is peeled off, and the adhesive layer 11 in which the direct bonding film 1 is exposed is printed layer 3 of the first display member 21. ) Is bonded to the surface of the side on which there is. At this time, since the adhesive layer 11 is excellent in the initial stage followable | trackability, generation | occurrence | production of a clearance gap and a float in the vicinity of the step | step by the printing layer 3 is suppressed.

Subsequently, the other peeling sheet 12b is peeled from the adhesive layer 11 of the direct bonding film 1, and the adhesive layer 11 and the 2nd display member 22 in which the direct bonding film 1 was exposed are shown. Is bonded together to obtain a laminate. As another example, the bonding order of the first display member 21 and the second display member 22 may be changed.

After that, the active energy ray is irradiated to the pressure-sensitive adhesive layer 11 in the laminate. In this embodiment, the said active energy ray curable component (C) in the adhesive layer 11 superposes | polymerizes by this, the adhesive layer 11 hardens, and it becomes the adhesive layer 11 'after hardening.

An active energy ray means what has energy both in an electromagnetic wave or a charged particle beam, Specifically, an ultraviolet-ray, an electron beam, etc. are mentioned. In this embodiment, it is preferable that it is an active energy ray containing the light which has a wavelength of 200-450 nm as an active energy ray.

An active energy ray that satisfies the above conditions is obtained by using a light source capable of irradiating ultraviolet rays such as a high pressure mercury lamp, a fusion H lamp, and a xenon lamp. In the case of the high-pressure mercury lamp, the main wavelength is 365 nm, but since the light having wavelengths of 405 nm and 436 nm is also irradiated, the light having a longer wavelength side than the main wavelength can be used for curing the pressure-sensitive adhesive layer 11.

The irradiation amount of the active energy ray is preferably 50 mW / cm 2 or more and 1000 mW / cm 2 or less. It is preferable that light quantity is 50 mJ / cm <2> or more, It is more preferable that it is 80 mJ / cm <2> or more, It is still more preferable that it is 200 mJ / cm <2> or more. Moreover, it is preferable that light quantity is 10000 mJ / cm <2> or less, It is more preferable that it is 5000 mJ / cm <2> or less, It is more preferable that it is 2000 mJ / cm <2> or less.

The display body 2 is obtained through the above process. In the display body 2, since the adhesive layer 11 'after hardening is excellent in step | following traceability also under high temperature, high humidity conditions, the display body 2 is high temperature, high humidity conditions (for example, 85 degreeC, 85% RH). , 72 hours), the occurrence of bubbles, lifting, peeling, etc. in the vicinity of the step is suppressed.

In addition, in the said display body 2, since the adhesive layer 11 'after hardening is excellent in blister resistance, the display body 2 is high-temperature, high-humidity conditions (for example, 85 degreeC, 85% RH, 72 hours), even when outgas is generated from the display member consisting of a plastic plate or the like, bubbles and floating at the interface between the adhesive layer 11 'and the display member 21, 22 after curing. It is suppressed that blisters, such as peeling, generate | occur | produce.

(5. Effect in the present embodiment)

In the present embodiment, the gel fraction of the pressure-sensitive adhesive layer before and after active energy ray irradiation is predetermined by lowering the light transmittance in the predetermined wavelength range of the pressure-sensitive adhesive layer of the direct bonding film and imparting ultraviolet absorbing ability to the pressure-sensitive adhesive layer. By controlling within the range, good step tracking and good blister resistance are achieved. Moreover, the said effect is further heightened by making the storage elastic modulus of the adhesive layer before and behind active energy ray irradiation and the adhesive force of the adhesive layer after active energy ray irradiation into a predetermined range.

As a specific structure of the adhesive which comprises the adhesive layer which implement | achieves such a characteristic, in the said adhesive, a (meth) acrylic acid ester copolymer and a thermal crosslinking agent harden | cure by a crosslinking reaction, and exist the crosslinked structure (three-dimensional network structure) formed, and In addition to being present, the active energy ray curable component is present as it is without polymerization (curing). In other words, hardened | cured material and an unhardened | cured material coexist in an adhesive.

A crosslinked structure is hardened | cured material, and predetermined cohesion force is obtained when an adhesive has a crosslinked structure. On the other hand, it is thought that the active energy ray curable component is present in the gap of the crosslinked structure as it is without curing (curing) as an uncured product. As a result, the pressure sensitive adhesive has a predetermined strength resulting from the crosslinked structure, and the active energy ray curable component, which is an uncured product, acts as a component that improves the plasticity of the pressure sensitive adhesive. Therefore, in the case where the adhesive is bonded to the adherend, even if there is a step in the adherend, the adhesive sufficiently follows the step, and even in the vicinity of the step, no gap such as a gap or lifting occurs between the adherend and the adhesive. .

And after an adhesive is bonded to a to-be-adhered body, an active energy ray is irradiated to the said adhesive. At this time, although the ultraviolet absorber contained in the adhesive absorbs an active energy ray, the wavelength range of the light which has sufficient absorbance for the photoinitiator to advance a polymerization reaction, and the wavelength range of the light which an ultraviolet absorber absorbs are shift | deviating. Therefore, the said photoinitiator is cleaved by the active energy ray which is not absorbed by a ultraviolet absorber, and the superposition | polymerization (curing) of the active energy ray curable component which exists without hardening is accelerated | stimulated. As a result, it is thought that a polymerization structure is formed so that it may become entangled with a crosslinked structure. Since the curing of the active energy ray-curable component is carried out in a state where it is sufficiently bonded to the adherend, the crosslinked structure and the polymerized structure interact appropriately after curing by the active energy ray, so that the step difference can be exhibited in a state before curing that is satisfactory. It can show an undeniable cohesion.

As described above, in the above-described embodiment, in the pressure-sensitive adhesive, by combining hardening (thermal curing) before bonding to the adherend and curing after bonding (active energy ray curing), the step tracking and the blister resistance are at a very high level. Can be achieved. Moreover, since an adhesive contains a ultraviolet absorber, the deterioration of the member which comprises a display body can be suppressed effectively.

Therefore, the display body which bonded together the structural member which has a level | step difference and another structural member using this adhesive can fully be protected from an ultraviolet-ray, and can maintain favorable image quality.

(6. Variation)

In the above-mentioned embodiment, although the direct bonding film has two peeling sheets 12a and 12b, any one or both of the peeling sheets 12a and 12b in the direct bonding film 1 may be abbreviate | omitted.

In addition, the first display member 21 may have a step other than the printing layer 3. Further, not only the first display member 21 but also the second display member 22 may have a step on the pressure-sensitive adhesive layer 11 'side after curing.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment at all, It may change into various aspects within the scope of this invention.

Example

Hereinafter, although an Example is used and this invention is demonstrated in detail, this invention is not limited to these Examples.

(Example 1)

1. Preparation of (meth) acrylic acid ester copolymer

60 mass parts of 2-ethylhexyl acrylate, 10 mass parts of isobornyl acrylate, 10 mass parts of N-acryloyl morpholine, and 20 mass parts of 2-hydroxyethyl acrylate are copolymerized, and a (meth) acrylic acid ester copolymer (A ) Was prepared. The molecular weight of the obtained (meth) acrylic acid ester copolymer (A) was measured by the method shown below, and the weight average molecular weight (Mw) was 500,000.

The weight average molecular weight (Mw) is the weight average molecular weight of polystyrene conversion measured (GPC measurement) on condition of the following using gel permeation chromatography (GPC).

(Measuring conditions)

GPC measuring device: manufactured by Tosoh Corporation, HLC-8020

GPC column (passed in the following order): manufactured by Tosoh Corporation

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

Measurement solvent: tetrahydrofuran

Measurement temperature: 40 ℃

2. Preparation of Adhesive Composition

100 mass parts (solid content conversion value; the same below) of (meth) acrylic acid ester copolymer (A) obtained above, 0.2 mass part of trimethylolpropane modified tolylene diisocyanate as a thermal crosslinking agent (B), and an active energy ray curable component ( C) 5.0 mass parts of ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate and 0.5 mass of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as photopolymerization initiator (D) And 3.0 parts by mass of 2-dihydroxy-4-methoxybenzophenone as the ultraviolet absorber (E), and 0.3 parts by mass of 3-glycidoxypropyltrimethoxysilane as the silane coupling agent (F), It stirred and diluted with methyl ethyl ketone, and obtained the coating solution of the adhesive composition of 50 mass% of solid content concentration.

3. Preparation of Direct Bonding Film

The coating solution of the obtained adhesive composition was apply | coated to the peeling process surface of the heavy peeling type peeling sheet (The Lintec company make, product name "SP-PET752150") which peeled the single side | surface of a polyethylene terephthalate film with a silicone type peeling agent with the knife coater. And a coating layer which consists of an adhesive which heat-processes at 90 degreeC for 1 minute and advances a thermal crosslinking reaction with respect to an application layer, and has a crosslinked structure comprised from a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B) Formed.

Subsequently, the light peeling type peeling sheet (The Lintec company make, product name "SP-PET382120") which peeled and treated the coating layer on the heavy peeling type peeling sheet obtained above, and the single side | surface of a polyethylene terephthalate film with a silicone type peeling agent is the said light peeling type peeling sheet. It is bonded so that the peeling process surface of a contact surface may contact a coating layer, and it cures under 23 degreeC and 50% RH conditions for 7 days, and the direct bonding film which has an adhesive layer of 50 micrometers in thickness, ie, a heavy peeling type peeling sheet / adhesive layer (thickness : 50 micrometers) / The direct bonding film which consists of a structure of a light peeling type peeling sheet was manufactured. In addition, the thickness of an adhesive layer is the value measured using the static-pressure thickness meter (The Tekla company make, product name "PG-02") based on JISK7130.

(Examples 2-9, Comparative Examples 1-4)

The direct bonding film was manufactured like Example 1 except having changed the kind and compounding quantity of a photoinitiator (D), and the kind and compounding quantity of a ultraviolet absorber (E) as shown in Table 1.

The details, such as the symbol of Table 1, are as follows.

((Meth) acrylic acid ester copolymer (A))

2EHA: 2-ethylhexyl acrylate

IBXA: isobornyl acrylate

ACMO: N-acryloyl morpholine

HEA: 2-hydroxyethyl acrylate

(Thermal crosslinking agent (B))

B1: trimethylolpropane modified tolylene diisocyanate

B2: trimethylolpropane modified xylene diisocyanate

(Active energy ray curable component (C))

C1: epsilon -caprolactone modified tris- (2-acryloxyethyl) isocyanurate

(Photoinitiator (D))

D1: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

D2: Mixing 1-hydroxycyclohexylphenyl ketone and benzophenone at a mass ratio of 1: 1.

(Ultraviolet absorber (E))

E1: 2-dihydroxy-4-methoxybenzophenone

E2: 2-methoxy-1-methylethyl acetate, benzenepropanoic acid, 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy, C7-9 Side and straight chain alkyl esters

E3: Octyl-3- (3-t-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl) propionate + 2-ethylhexyl-3- (3 -t-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl) propionate

(Silane coupling agent (F))

F1: 3-glycidoxypropyltrimethoxysilane

In addition, an acetonitrile solution having a concentration of 0.1% by mass of the photopolymerization initiators D1 and D2 was prepared, and an absorbance in the range of 200 to 500 nm in the solution was measured using an ultraviolet visible near infrared (UV-Vis-NIR) spectrophotometer. It measured using (the Shimadzu Corporation make, product name "UV-3600"). Based on the result, the absorbance of wavelength 380 nm and the absorption maximum wavelength in the said measurement range were derived. The results are shown in Table 1.

(Evaluation of Ultraviolet Absorption Capacity)

The light peelable peeling sheet was peeled from the direct bonding film obtained by the Example and the comparative example, and the exposed adhesive layer was affixed on soda-lime glass (made by Nippon Panglass Co., Ltd.) of thickness 1.1mm. Thereafter, the heavy release type peeling sheet was peeled off to obtain a sample for evaluation before active energy ray irradiation. Moreover, the ultraviolet-ray was irradiated directly on the exposed adhesive layer on the following conditions, it hardened | cured and the adhesive layer was made into the adhesive layer after hardening, and the sample for evaluation after active energy ray irradiation was obtained.

<UV irradiation condition>

Use of high pressure mercury lamp

Illuminance 200 ㎽ / ㎠, light quantity 2000 mJ / ㎠

UV illuminance and photometric meter use `` UVPF-A1 '' manufactured by iGraphics

The adhesive layer of the obtained evaluation sample was irradiated with light in the wavelength range of 300-800 nm with an ultraviolet visible near-infrared spectrophotometer (The Shimadzu Corporation make, UV-3600), and the light transmittance of an adhesive layer was measured, and it is 380 nm. The light transmittance of the adhesive layer in (before active energy ray irradiation and after active energy ray irradiation) was derived, respectively. It was judged that the sample whose light transmittance of the adhesive layer in 380 nm derived was 40% or less in ultraviolet absorbing ability, and the sample in which the light transmittance of the adhesive layer in 380 nm derived was more than 40% was judged to have no ultraviolet absorbing ability. . The results are shown in Table 2.

In Comparative Example 1, which does not have ultraviolet absorbing ability, the transmittance is greater than 0 (before ultraviolet rays are not absorbed and begins to transmit) around 300 nm in wavelength before and after active energy ray irradiation, and the transmittance is already at wavelength 350 nm. The result that it exceeds 80% was obtained.

On the other hand, in Examples 1-9, the transmittance | permeability is 0 to the wavelength 370nm, and when it exceeds wavelength 370nm, although the transmittance | permeability becomes larger than 0, even at wavelength 380nm, it is much below 30% as shown in Table 2. That is, in the Example and the comparative example, it was confirmed that a very big difference arises about the ultraviolet absorbing ability in the ultraviolet range of wavelength 300-380 nm at least.

(Evaluation of gel fraction: before irradiation of active energy ray)

The direct bonding film obtained by the Example and the comparative example was cut | judged to 80 mm x 80 mm size, the adhesive layer was wrapped with polyester mesh (mesh size 200), the mass was weighed by precision balance, and the said mesh alone The mass of only an adhesive was computed by subtracting the mass. Let the mass at this time be M1.

Next, the adhesive wrapped in the said polyester mesh was immersed in ethyl acetate for 72 hours at room temperature (23 degreeC). Then, the adhesive was taken out, air-dried for 24 hours in the environment of the temperature of 23 degreeC, and 50% of a relative humidity, and also it dried in 80 degreeC oven for 12 hours. After drying, the mass was weighed by precision balance, and the mass of the pressure-sensitive adhesive was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M2. Gel fraction (%) is represented by (M2 / M1) x100. Thereby, the gel fraction (before active energy ray irradiation) of the adhesive was derived. The results are shown in Table 2.

(Evaluation of gel fraction: after irradiation with active energy rays)

The light-peelable peeling sheet was peeled from the direct bonding films obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was directly irradiated with active energy rays under the above-described conditions, and the pressure-sensitive adhesive layer was cured to obtain a pressure-sensitive adhesive layer after curing. . The gel fraction (after active energy ray irradiation; direct irradiation) was derived similarly to the above about the adhesive after hardening of this adhesive layer after hardening. The results are shown in Table 2.

(Evaluation of gel fraction: ratio of gel fraction of pressure-sensitive adhesive before and after active energy ray irradiation)

The ratio of the gel fraction of the adhesive before and after active energy ray irradiation was derived from the following formula from the gel fraction of the adhesive before the derived active energy ray irradiation and the gel fraction of the cured adhesive after active energy ray irradiation. The results are shown in Table 2.

Ratio of gel fraction of pressure sensitive adhesive before and after active energy ray irradiation = (gel fraction of cured pressure sensitive adhesive after active energy ray irradiation / gel fraction of pressure sensitive adhesive before active energy ray irradiation)

(Evaluation of Curability)

When the gel fraction after active energy ray irradiation is larger than the gel fraction before active energy ray irradiation, the adhesive layer is cured. Therefore, the ratio of the gel fraction before and after the derived active energy ray irradiation is 1.05 or more. Curability was described as "(circle)" and the curability of the sample whose ratio of gel fraction is less than 1.05 was described as "x". The results are shown in Table 2.

(Evaluation of storage modulus: before irradiation with active energy ray)

The light peelable peeling sheet was peeled off from the direct bonding film obtained by the Example and the comparative example, the exposed adhesive layer was punched out in circular shape of diameter 10mm, and the sample for evaluation for measuring the viscoelasticity of an adhesive layer was obtained. Using a viscoelasticity measuring device (manufactured by T. A. Instruments, Inc.), a strain of frequency 1 Hz was applied to the sample for evaluation, and the storage modulus at -50 to 150 ° C was measured. The results are shown in Table 2.

(Evaluation of storage modulus: after irradiation with active energy rays)

The light-peelable release sheet was peeled from the direct bonding films obtained in Examples and Comparative Examples, and the exposed adhesive layer was directly irradiated with an active energy ray under the conditions described above to cure the adhesive layer to obtain an adhesive layer after curing. About this adhesive layer after this hardening, storage elastic modulus (after active energy ray irradiation) was measured similarly to the above. The results are shown in Table 2.

(Evaluation of storage modulus: ratio of storage modulus of pressure-sensitive adhesive before and after curing)

The ratio of the storage elastic modulus of the adhesive before and after active energy ray irradiation was derived from the following formula from the storage elastic modulus of the adhesive before derivation of active energy ray irradiation, and the storage elastic modulus of the cured adhesive after active energy ray irradiation. The results are shown in Table 2.

Ratio of storage elastic modulus of the adhesive before and after active energy ray irradiation = (storage elastic modulus of the cured adhesive after active energy ray irradiation / storage elastic modulus of the adhesive before active energy ray irradiation)

(Evaluation of adhesion)

Easy peeling of the polyethylene terephthalate (PET) film (Toyobo Co., Ltd. product name "PET A4300", thickness: 100 micrometers) which peels a light peeling type | mold peeling sheet from the direct bonding film obtained by the Example and the comparative example, and has an easily bonding layer. It bonded together to the layer and obtained the laminated body of a peeling sheet / adhesive layer (50 micrometers) / PET film. The obtained laminated body was cut out to 25 mm width and 150 mm length, and it was set as the sample.

After peeling a heavy peeling type peeling sheet from the said sample in 23 degreeC, 50% RH environment, and exposing the exposed adhesive layer to soda-lime glass (made by Nippon Panglass Co., Ltd., total light transmittance: 99% or more), 2 kg of The roller was pressed by one reciprocation. Next, the active energy ray was irradiated under the conditions mentioned above over soda-lime glass, the adhesive layer was hardened, and it was set as the adhesive layer after hardening. Then, after leaving for 24 hours on 23 degreeC and 50% RH conditions, using the tensile tester (Orientec Co., Tensilon), adhesive force (N /) was carried out on the conditions of peeling rate 300mm / min and peeling angle 180 degree. 25 mm) was measured. Conditions other than those described here were measured in accordance with JIS Z0237: 2009. The results are shown in Table 2.

(Evaluation of haze value)

The light peeling type peeling sheet was peeled from the direct bonding film obtained by the Example and the comparative example, and it stuck on soda-lime glass (made by Nippon Panglass Co., Ltd., total light transmittance: 99% or more) of thickness 1.1mm. Then, the active energy ray was directly irradiated over the soda-lime glass on the conditions mentioned above, the adhesive layer was hardened | cured, it was made into the adhesive layer after hardening, and the heavy peeling type peeling sheet was peeled off, and the sample for evaluation was obtained.

The measurement light of the haze meter (The Nippon Denshoku industrial company make, product name "NDH-7000") was incident from the adhesive layer side of the said evaluation sample, and haze value (%) was measured. The measurement was performed 3 times each, and the average value was computed. Conditions other than what was described here were measured based on JISK7136: 2000. The results are shown in Table 2.

(Evaluation of blister resistance)

The adhesive layer of the direct bonding film obtained by the Example and the comparative example was affixed on soda-lime glass (made by Nippon Panglass Co., Ltd.). Moreover, the heavy peeling type peeling sheet was peeled from a direct bonding film, and the exposed adhesive layer was the surface of the polycarbonate layer side of the resin plate (thickness: 0.7 mm, no ultraviolet absorber containing) which has a polymethyl methacrylate layer and a polycarbonate layer. The sample for evaluation was obtained by affixing on. Then, the sample for evaluation was autoclaved for 30 minutes on 50 degreeC and 0.5 Mpa conditions, and it was left to stand by normal pressure, 23 degreeC, and 50% RH for 24 hours.

About the adhesive layer after autoclave processing, ultraviolet-ray was irradiated on the conditions mentioned above over the said resin plate, the adhesive layer was hardened, and it was set as the adhesive layer after hardening. Then, it stored for 240 hours on 85 degreeC and 85% RH high temperature, high humidity conditions. Then, the state in the interface of an adhesive layer and a to-be-adhered body after hardening was visually confirmed, and the blister resistance was evaluated by the following references | standards. The results are shown in Table 2.

◎… No bubbles, lifting or peeling off

○… Slight microfoaming (no large bubbles or flaking)

×… Bubbles, bubble marks, or lifting or peeling

(Evaluation of Step Following)

UV curable ink (product made by Teikoku Ink Co., Ltd., product name "POS-911") on the surface of a glass plate (NSG Precision Transfer, product name "Corning Glass Eagle XG", length 90 mm x width 50 mm x thickness 0.5 mm) ) Was screen-printed in a frame shape (appearance: 90 mm length × 50 mm width, 5 mm width) so that the coating thickness was any one of 5 µm, 10 µm and 20 µm. Subsequently, ultraviolet rays were irradiated (80 W / cm 2, metal halide lamp 2, lamp height 15 cm, belt speed 10-15 m / min), the printed ultraviolet curable ink was cured, and the step by printing (step difference) Height: any one of 5 micrometers, 10 micrometers, and 20 micrometers) the glass plate with a level | step difference was manufactured.

The light-peelable peeling sheet was peeled off from the direct bonding films obtained in Examples and Comparative Examples, and the pressure-sensitive adhesive layer covered the entire surface of the frame-shaped printing using a laminator (manufactured by Fujipla, product name "LPD3214") in the exposed pressure-sensitive adhesive layer. Each step was laminated on a glass plate with a step. Subsequently, the peelable peeling sheet was peeled off to expose the pressure-sensitive adhesive layer, and using the laminator, a glass plate (NSG Precision Co., Ltd. product name "Corning Glass Eagle XG", vertical 90 mm × width 50 mm × thickness 0.5 was used on the surface of the pressure-sensitive adhesive layer. Mm) was laminated with the laminator, and the sample for evaluation was obtained. Then, the sample for evaluation was autoclaved for 30 minutes on 50 degreeC and 0.5 Mpa conditions, and it was left to stand by normal pressure, 23 degreeC, and 50% RH for 24 hours.

(A) Evaluation of initial step followability

In each step | step, it is checked visually whether the adhesive layer (especially in the vicinity of the step | step by a printing layer) of the sample for evaluation obtained by the said description is free of air bubbles, lifting, and peeling off. Step followability was evaluated. The results are shown in Table 2.

A: It follows every step and air bubble and peeling off are not seen.

B: When the height of the step was 20 µm, air bubbles and lifting peeled off were observed in the stepped part.

C: When the height of the level | step difference was 10 and 20 micrometers, foam | bubble and lifting peeling were seen in a step part.

D: Bubble | bubble and lifting peeling are seen also in any step part.

(B) Evaluation of durability (step followability after durability)

About the adhesive layer of the evaluation sample obtained by the said description, an active energy ray was irradiated on the conditions mentioned above over the said glass plate, the adhesive layer was hardened, and it was set as the adhesive layer after hardening. Subsequently, it stored for 240 hours under 85 degreeC and 85% RH high temperature, high humidity conditions (durability test), and after that, an adhesive layer (in particular, the vicinity of a step by a printing layer) was visually confirmed, and the said initial step followability Based on the evaluation criteria, the step tracking following durability was evaluated. The results are shown in Table 2.

(Evaluation of moisture-resistant whitening)

The adhesive layer of the direct bonding film obtained by the Example or the comparative example was affixed on soda-lime glass (made by Nippon Panglass Co., Ltd.). Moreover, the heavy peeling type peeling sheet was peeled from a direct bonding film, and the exposed adhesive layer was the surface of the polycarbonate layer side of the resin plate (thickness: 0.7 mm, no ultraviolet absorber containing) which has a polymethyl methacrylate layer and a polycarbonate layer. The sample for evaluation was obtained by affixing on. Then, the sample for evaluation was autoclaved for 30 minutes on 50 degreeC and 0.5 Mpa conditions, and it was left to stand by normal pressure, 23 degreeC, and 50% RH for 24 hours. Then, haze value (%) before evaluation of moisture-resistant whitening resistance was measured according to JIS K7136: 2000 using the haze meter (The Nippon Denshoku industrial company make, product name "NDH2000").

Next, the said laminated body was stored for 240 hours on 85 degreeC and 85% RH high temperature, high humidity conditions. Then, it returns to normal temperature and humidity of 23 degreeC and 50% RH, and measures the haze value (%) after evaluation of moisture-heat whitening resistance according to JIS K7136: 2000 about the said laminated body using said haze meter. It was. In addition, the said haze value was measured within 30 minutes after returning a laminated body to normal temperature and humidity.

The moisture-resistant heat bag based on the following criteria from the value (the difference of the haze value before and behind durability: point) after subtracting the haze value (%) before evaluation of moisture-resistant whitening resistance from the haze value (%) after evaluation of moisture-resistant whitening resistance. Mars was evaluated. The results are shown in Table 2.

(Double-circle): The difference of the haze value before and behind endurance is less than 1.5 points.

(Circle): The difference of haze value before and after endurance is 1.5 points or more and 5 points or less.

X: The difference of the haze value before and after endurance exceeds 5 points.

The direct bonding film of this invention can be used suitably for bonding a display body structural member, for example.

One… Direct bonding film
11... Adhesive layer
12a, 12b... Peeling sheet
2… Indicator
21... First indicator member
22... Second indicator member
3... Printed layer

Claims (11)

As a direct bonding film which has an active energy ray curable adhesive layer,
The light transmittance of the said adhesive layer in wavelength 380nm is 40% or less,
Before active energy ray irradiation to an adhesive layer, the gel fraction of the said adhesive layer is 20% or more and 55% or less,
After active energy ray irradiation to an adhesive layer, the gel fraction of the said adhesive layer is 40% or more and 90% or less,
The ratio of the gel fraction of the said adhesive layer after active energy ray irradiation to the gel fraction of the said adhesive layer before active energy ray irradiation is 1.05 or more, The direct bonding film characterized by the above-mentioned. The method of claim 1,
The ratio of the storage elastic modulus of the said adhesive layer after active energy ray irradiation to the storage elastic modulus of the said adhesive layer before active energy ray irradiation is 1.20 or more, The direct bonding film characterized by the above-mentioned. The method of claim 2,
After active energy ray irradiation to an adhesive layer, the storage elastic modulus of the said adhesive layer is 0.05 Mpa or more and 0.50 Mpa or less, The direct bonding film characterized by the above-mentioned. The method of claim 2 or 3,
Before the active energy ray irradiation to an adhesive layer, the storage elastic modulus of the said adhesive layer is 0.01 Mpa or more and 0.20 Mpa or less, The direct bonding film characterized by the above-mentioned. The method according to any one of claims 1 to 3,
After active energy ray irradiation to an adhesive layer, the adhesive force of the said adhesive layer is 20 N / 25 mm or more, The direct bonding film characterized by the above-mentioned. The method according to any one of claims 1 to 3,
The pressure-sensitive adhesive layer,
A crosslinked structure composed of a (meth) acrylic acid ester copolymer and a thermal crosslinking agent,
An active energy ray curable component,
A photoinitiator whose absorbance at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass is 1.0 or more;
The direct bonding film which consists of an adhesive which has a ultraviolet absorber. The method according to any one of claims 1 to 3,
The direct bonding film has a release sheet,
Both main surfaces of the said adhesive layer are comprised in contact with the peeling surface of the said peeling sheet, The direct bonding film characterized by the above-mentioned. A first indicator member,
A second indicator member,
A display body having a pressure-sensitive adhesive layer after curing bonding the first display member and the second display member to each other,
The said adhesive layer after hardening is hardened | cured the adhesive layer which the direct bonding film of Claim 1 has, The display body characterized by the above-mentioned. The method of claim 8,
At least one of the first display member and the second display member has a step,
The said adhesive layer after the said hardening is bonded together along the said step | step, The display body characterized by the above-mentioned. A process of manufacturing a laminate formed by bonding the first display member and the second display member through the pressure-sensitive adhesive layer included in the direct bonding film according to claim 1;
And a step of irradiating an active energy ray to the pressure-sensitive adhesive layer of the laminate to cure the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer after curing. The method of claim 10,
At least one of the first display member and the second display member has a step,
The said adhesive layer is bonded along the said step | step, The manufacturing method of the display body characterized by the above-mentioned.

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