KR20180092803A - Adhesive sheet - Google Patents

Abstract

An objective of the present invention is to provide an adhesive sheet which can suppress the generation of moiré in a display body and has excellent step following properties. To this end, provided is the adhesive sheet (1) which includes an adhesive layer (11) having the haze value of 30% or more to 95% or less, wherein the breaking elongation of the adhesive layer (11) by a tensile test is 500% or more, and the gel fraction of an adhesive constituting the adhesive layer (11) is 20% or more to 95% or less. The adhesive is obtained by crosslinking an adhesive composition containing a (meth)acrylic acid ester polymer (A), a polyrotaxane compound (B), and a crosslinking agent (C).

Description

ADHESIVE SHEET [0002]

The present invention relates to a pressure-sensitive adhesive sheet, and more particularly to a pressure-sensitive adhesive sheet suitable for bonding display member constituting members.

In recent years, a liquid crystal panel is often used as a display (display). In such a liquid crystal panel, moire is likely to occur due to the recent demand for high definition image quality. Moire refers to a shape of a stripe that is visually generated by a deviation of the period of a certain rule shape as a result of overlapping, thereby giving an influence to the visibility of the display. Particularly, in the touch panel, moiré is apt to occur by using two layers of the patterned transparent conductive film. From the viewpoint of solving such a problem with a pressure-sensitive adhesive layer, attention has been paid to a pressure-sensitive adhesive layer having light-diffusing properties.

As such a light-diffusing pressure-sensitive adhesive layer, for example, Patent Document 1 discloses a pressure-sensitive adhesive layer comprising (A) a (meth) acrylic acid ester copolymer, (b) a (meth) acrylic ester (B) a fine particle having an average particle size of 0.1 to 20 占 퐉, wherein the storage elastic modulus at 23 占 폚 and the storage modulus at 23 占 폚 (G ') of 2 MPa or more and 20 MPa or less.

Further, Patent Document 2 discloses a method for producing a copolymer containing at least one kind of alkyl (meth) acrylate monomer having an alkyl group having from 1 to 14 carbon atoms and a copolymerizable monomer containing a hydroxyl group, a copolymerizable monomer containing a carboxyl group, Discloses a light diffusion pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition comprising a copolymer comprising at least one member selected from the group consisting of a monomer, a monomer and an aromatic group-containing monomer, a crosslinking agent, and silicon-based particles (fine particles).

Patent Document 3 discloses _a radically polymerizable monomer in which the refractive index n _b of the (meth) acrylic polymer (A) when the homopolymer is used is larger than the refractive index n _a of the (meth) acrylic polymer (A) (Meth) acrylate copolymer (B) obtained by blending and polymerizing a monomer having an aromatic group such as styrene monomer, benzyl acrylate, phenoxyethyl acrylate and the like; And a light-diffusing pressure-sensitive adhesive layer obtained by crosslinking a light-diffusing pressure-sensitive adhesive composition containing a crosslinking agent.

Japanese Patent No. 5149533 Japanese Patent Laid-Open Publication No. 2015-86297 Japanese Patent Application Laid-Open No. 2010-159333

Incidentally, the liquid crystal panel typically includes a liquid crystal module and a protective panel for protecting the liquid crystal module. A gap is provided between the liquid crystal module and the protective panel so that the deformed protective panel does not hit the display module even when the protective panel is deformed by an external force.

However, when such air gaps are present, there is a problem that the reflection loss of light due to the refractive index difference between the protective panel and the air layer and the refractive index difference between the air layer and the liquid crystal module is large, resulting in deterioration of the display quality.

Thus, it has been proposed to improve the image quality of the display by filling the space between the protective panel and the liquid crystal module with a pressure-sensitive adhesive layer. However, on the side of the liquid crystal module of the protective panel, the printed layer on the framed frame may exist as a step. If the pressure-sensitive adhesive layer does not follow the step, the pressure-sensitive adhesive layer is excited near the step, thereby causing reflection loss of light. Therefore, the above-mentioned pressure-sensitive adhesive layer is required to follow step difference.

When the pressure-sensitive adhesive layer disclosed in Patent Document 1 is used between a protective panel and a liquid crystal module, the pressure-sensitive adhesive layer has a high storage elastic modulus (G ') of 2 MPa or more and 20 MPa or less and is rigid. Not suitable for the required application. As in the case of the pressure-sensitive adhesive layer disclosed in Patent Document 1, since the pressure-sensitive adhesive layer disclosed in Patent Document 2 is hardened by containing fine particles, it is difficult to follow the step, and it is difficult to satisfy the required step-following property.

Further, in the case where fine particles are contained in the pressure-sensitive adhesive as in Patent Documents 1 and 2, it is necessary to use a dedicated pipe or a dedicated kiln at the time of manufacturing the pressure-sensitive adhesive, and further, There is also the risk of Nation. In addition, it is also necessary to disperse the fine particles in the pressure-sensitive adhesive, which causes not only the raw material cost of the fine particles but also an increase in the production cost.

On the other hand, the pressure-sensitive adhesive layer which does not use the fine particles of Patent Document 3 is preferable from the point that the above-mentioned problem does not occur. However, since the pressure-sensitive adhesive layer is hard due to the modified (meth) acrylate-based copolymer (B) obtained by polymerizing the monomer having an aromatic group, the pressure-sensitive adhesive layer is also poor in step-wise followability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive sheet which is capable of suppressing occurrence of moiré in a display member and excellent in step-following ability.

In order to achieve the above object, firstly, the present invention provides a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer has a haze value of 30% or more and 95% or less, ) Elongation is 500% or more, and the gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is 20% or more and 95% or less (Invention 1).

The pressure-sensitive adhesive sheet according to the invention (Invention 1) satisfies the physical properties described above, thereby suppressing occurrence of moiré in the display member and also excellent in step-following ability.

In the above invention (Invention 1), it is preferable that the pressure-sensitive adhesive contains a polyrotaxane compound (invention 2).

In the above invention (Invention 1 or 2), the pressure-sensitive adhesive is a pressure-sensitive adhesive which is obtained by crosslinking a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester polymer (A), a polyrotaxane compound (B) (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the pressure-sensitive adhesive contains no filler (invention 4).

In the above invention (inventions 1 to 4), two release sheets are provided, and it is preferable that the pressure-sensitive adhesive layer is sandwiched between the release sheets so as to come into contact with the release surfaces of the two release sheets (Invention 5).

INDUSTRIAL APPLICABILITY The pressure-sensitive adhesive sheet according to the present invention is capable of suppressing the generation of moire in the display member and also excellent in step-following ability.

1 is a sectional view of a pressure-sensitive adhesive sheet according to an embodiment of the present invention;
2 is a sectional view of a display body according to an embodiment of the present invention;

Hereinafter, an embodiment of the present invention will be described.

[Adhesive sheet]

The pressure-sensitive adhesive sheet according to one embodiment of the present invention has at least a pressure-sensitive adhesive layer, and is preferably formed by laminating a release sheet on one side or both sides of the pressure-sensitive adhesive layer.

Fig. 1 shows a specific configuration as an example of the pressure-sensitive adhesive sheet according to the present embodiment.

1, the pressure-sensitive adhesive sheet 1 according to one embodiment is formed by two sheets of release sheets 12a and 12b and two sheets of release sheets 12a and 12b in contact with the release surfaces of the two release sheets 12a and 12b, And a pressure-sensitive adhesive layer 11 sandwiched between the release sheets 12a and 12b. In the present specification, the release surface of the release sheet refers to a surface having release properties in the release sheet, and includes both the surface subjected to the release treatment and the surface exhibiting the release property without performing the release treatment.

1. Properties

The haze value of the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 according to the present embodiment is 30% or more and 95% or less and the breaking elongation of the pressure-sensitive adhesive layer 11 by the tensile test is 500% The gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 is 20% or more and 95% or less. By satisfying all of these physical properties, the pressure-sensitive adhesive sheet 1 can suppress the occurrence of moiré in the display member, and is also excellent in step-wise followability.

Describing this step following property specifically, the pressure-sensitive adhesive layer in the present embodiment is easy to follow the step when attached to a display member having a step, and it is suppressed from occurring in the vicinity of the step, do. Further, even when the substrate is left under the conditions of high temperature and high humidity, for example, under the conditions of 85 캜 and 85% RH for 72 hours, bubbling, lifting, peeling, and the like are prevented from occurring in the vicinity of the step.

(1) Haze value

The haze value of the pressure-sensitive adhesive layer 11 is 30% or more, preferably 35% or more, particularly preferably 40% or more, and more preferably 50% or more, as a lower limit value. The lower limit of the haze value of the pressure-sensitive adhesive layer 11 is as described above, whereby the occurrence of moire in the display (display) obtained by the pressure-sensitive adhesive layer 11 can be suppressed.

The upper limit of the haze value of the pressure-sensitive adhesive layer 11 is 95% or less, preferably 90% or less, and particularly preferably 85% or less. With the upper limit value of the haze value, the desired transparency can be ensured and the image of the display unit module can be displayed with a good image quality in the obtained display. The haze value in this specification is a value measured in accordance with JIS K7136: 2000.

(2)

The elongation at break of the pressure-sensitive adhesive layer 11 by the tensile test is 500% or more, preferably 550% or more, and particularly preferably 700% or more as the lower limit value. If the lower limit value of the elongation at break of the pressure-sensitive adhesive layer 11 is above the above-mentioned gel fraction of the pressure-sensitive adhesive, the pressure-sensitive adhesive layer 11 is excellent in step-wise followability.

On the other hand, the upper limit value of the elongation at break of the pressure-sensitive adhesive layer 11 by the tensile test is not particularly limited, but is preferably not more than 3000%, more preferably not more than 2,500%, particularly preferably not more than 2000%.

Specifically, in the tensile test, the pressure-sensitive adhesive layer alone is formed into a thickness of 500 mu m, a width of 10 mm, a length in the elongation direction of 75 mm (the length of the measurement site is 20 mm) At a speed of 200 mm / min.

The film strength by the tensile test of the pressure-sensitive adhesive layer 11 is preferably 5 N / mm 2 or less, more preferably 2 N / mm 2 or less, and more preferably 1 N / mm 2 or less from the viewpoint of excellent step- Particularly preferred. On the other hand, the film strength is preferably 0.01 N / mm 2 or more, more preferably 0.1 N / mm 2 or more, and particularly preferably 0.5 N / mm 2 or more from the viewpoint of excellent step traceability under high temperature and high humidity conditions. The film strength is calculated by dividing the stress at break in the tensile test by the cross-sectional area (thickness x width) of the pressure-sensitive adhesive layer.

(3) Gel fraction

The upper limit value of the gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 is 95% or less, preferably 90% or less, particularly preferably 85% or less, more preferably 80% or less. If the upper limit value of the gel fraction of the pressure sensitive adhesive is the above, the pressure sensitive adhesive layer 11 is excellent in the step following ability in accordance with the above elongation at break of the pressure sensitive adhesive layer (11).

The lower limit value of the gel fraction of the pressure-sensitive adhesive is preferably 20% or more, particularly preferably 30% or more, and more preferably 40% or more. If the lower limit of the gel fraction of the pressure-sensitive adhesive is above, the cohesive force of the pressure-sensitive adhesive increases, and the step-wise followability under high-temperature and high-humidity conditions is more excellent. The method of measuring the gel fraction of the pressure-sensitive adhesive is as shown in the following test examples.

(4) Total light transmittance

The total light transmittance of the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 according to the present embodiment is preferably 90% or more, particularly preferably 91% or more, more preferably 92% or more. When the value of the total light transmittance is the above value, high transparency can be ensured, and in the obtained display, the image of the display module can be displayed with good image quality. The total light transmittance in the present specification is a value measured in accordance with JIS K7361-1: 1997.

(5) Adhesion

The adhesive force of the pressure-sensitive adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 10 N / 25 mm or more as the lower limit value, particularly preferably 12 N / 25 mm or more, and more preferably 15 N / 25 mm or more. If the lower limit of the adhesive force is above, the step following property under the high temperature and high humidity condition is more excellent. The adhesive force of the pressure-sensitive adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 50 N / 25 mm or less as an upper limit value, more preferably 40 N / 25 mm or less, particularly preferably 35 N / Do. If the upper limit of the adhesive force of the pressure-sensitive adhesive sheet 1 is above, good reworkability can be obtained, and if a misalignment occurs, the expensive display member can be reused.

Here, the adhesive force in this specification refers basically to the adhesive force measured by the 180-degree peeling technique in accordance with JIS Z0237: 2009, but the measurement sample has a width of 25 mm and a length of 100 mm, Is pressed against the adherend and pressurized at 0.5 MPa and 50 캜 for 20 minutes and then left under the conditions of normal pressure, 23 캜 and 50% RH for 24 hours, and then measured at a peeling rate of 300 mm / min.

2. Each member

2-1. The pressure-

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 according to the present embodiment is not particularly limited as long as it satisfies the above-described physical properties, but it is preferable that the pressure-sensitive adhesive contains a polyrotaxane compound, It is easy to satisfy the physical properties.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 is preferably a pressure-sensitive adhesive obtained by crosslinking a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester polymer (A), a polyrotaxane compound (B) and a crosslinking agent Do. Such a pressure-sensitive adhesive easily satisfies the above-mentioned physical properties.

The (meth) acrylic acid ester polymer (A) preferably has a weight average molecular weight of 300,000 or more and less than 1,500,000, and further preferably contains at least one of a hydroxyl group-containing monomer and a carboxyl group-containing monomer as a monomer unit constituting the polymer Containing monomer is contained in an amount of less than 20% by mass and the carboxyl group-containing monomer is contained in an amount of less than 15% by mass in the case of containing a hydroxyl group-containing monomer . The polyrotaxane compound (B) preferably has a cyclic molecule containing a reactive group. (Hereinafter also referred to as " pressure-sensitive adhesive Q ") formed by crosslinking a pressure-sensitive adhesive composition containing a component satisfying these requirements (hereinafter sometimes referred to as "pressure-sensitive adhesive composition P" easy. In the present specification, the term "(meth) acrylic acid" means both of acrylic acid and methacrylic acid. The same is true of other similar terms. The term " polymer " also includes the concept of " copolymer ".

When the adhesive composition P is crosslinked, the reactive group of the crosslinking agent (C) reacts with the reactive group of the cyclic molecule of the polyrotaxane compound (B). The crosslinking agent adduct formed by the reaction is low in compatibility with the (meth) acrylic acid ester polymer (A), so that the haze value of the obtained pressure sensitive adhesive is increased. The other reactive group of the crosslinking agent (C) added to the crosslinking agent additionally reacts with the carboxyl group derived from the hydroxyl group-containing monomer or the carboxyl group-containing monomer derived from the hydroxyl group-containing monomer of the (meth) acrylic acid ester polymer (A) . The content of the hydroxyl group-containing monomer and the carboxyl group-containing monomer is relatively small, so that the (meth) acrylic acid ester polymer (A) reacts directly with the reactive group of the crosslinking agent (C) without interposing the polyrotaxane compound , It is presumed that the crosslinking agent adduct of the polyrotaxane compound (B) is preferentially formed, whereby the haze value of the obtained pressure sensitive adhesive is increased. With such a pressure-sensitive adhesive having a high haze value, generation of moire in the display body is effectively suppressed.

Here, the polyrotaxane compound (B) has a mechanical bond between a cyclic molecule and a linear molecule passing therethrough, so that the cyclic molecule can move freely in a linear molecular phase. The (meth) acrylic acid ester polymer (A) binds to one cyclic molecule of the polyrotaxane compound (B) via the crosslinking agent (C) in the crosslinking agent addition by the hydroxyl group or the carboxyl group of the polymer, It is presumed that the other (meth) acrylic acid ester polymer (A) binds to another cyclic molecule of the polyrotaxane compound (B). As a result, a structure (crosslinked structure) in which a plurality of (meth) acrylic acid ester polymers (A) are crosslinked via the above-mentioned polyrotaxane compound (B) having mechanical bonding is formed. The pressure-sensitive adhesive according to the present embodiment can be designed in a flexible manner because it does not require fine particles, and includes the above-mentioned crosslinked structure, whereby the stress relaxation property is excellent and the step following property is excellent.

It is not necessary that all of the pressure-sensitive adhesive Q have the above-mentioned structure, and the structure in which the two (meth) acrylic acid ester polymers (A) are directly bonded by the crosslinking agent (C) without interposing the polyrotaxane compound And the like.

As described above, since the pressure sensitive adhesive Q has a high haze value (specifically, 30% or more) and can be designed in a flexible manner, it is possible to suppress the occurrence of moiré in the display body, great.

In addition, according to the pressure-sensitive adhesive Q, since a high haze value can be obtained without using fine particles, it is not necessary to use a dedicated pipe or a dedicated kiln, and the risk of contamination to other products not containing fine particles none. In addition, as the fine particles as the raw material, it is also unnecessary to disperse the fine particles in the pressure sensitive adhesive, so that the cost can be reduced.

(1) Each component

(1-1) Synthesis of (meth) acrylic acid ester polymer (A)

The (meth) acrylic acid ester polymer (A) in the present embodiment preferably contains at least one of a hydroxyl group-containing monomer and a carboxyl group-containing monomer as a monomer unit constituting the polymer.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (Meth) acrylate such as 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, from the viewpoint of reactivity with the crosslinking agent (C) and copolymerization with other monomers, ) 2-hydroxyethyl acrylate or 4-hydroxybutyl (meth) acrylate is preferable. These may be used alone or in combination of two or more.

When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, the content thereof is preferably less than 20 mass%, particularly preferably not more than 18 mass% % Or less. If the content of the hydroxyl group-containing monomer is less than 20 mass%, the hydroxyl group of the hydroxyl group-containing monomer does not interfere with the reaction of the reactive group of the crosslinking agent (C) with the reactive group of the cyclic molecule of the polyrotaxane compound (B) An increase in the haze value by the crosslinking agent adduct of the taxane compound (B) is sufficiently ensured. The content of the hydroxyl group-containing monomer is more preferably 10% by mass or less, still more preferably 4% by mass or less, more preferably 2% by mass or less, from the viewpoint of obtaining a higher haze value while satisfactorily maintaining the step- Is particularly preferable.

When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, the content thereof is preferably 0.1 mass% or more, particularly preferably 0.3 mass% More preferably 0.5% by mass or more. When the content of the hydroxyl group-containing monomer is 0.1% by mass or more, the crosslinking structure described above is formed in the pressure-sensitive adhesive, and the pressure-sensitive adhesive maintains excellent stress relaxation property and excellent cohesion.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. When the (meth) acrylic acid ester polymer (A) contains a monomer having a carboxyl group as a monomer unit constituting the polymer, it is preferable that the pressure-sensitive adhesive obtained from the above is used in view of adhesiveness, reactivity with the crosslinking agent (C) Acrylic acid is preferable from the standpoint of the influence on the reaction of the hydroxyl group with the crosslinking agent (C) and the copolymerization with other monomers. These may be used alone or in combination of two or more.

When the (meth) acrylic acid ester polymer (A) contains a monomer having a carboxyl group as a monomer unit constituting the polymer, the content is preferably less than 15 mass%, particularly preferably 10 mass% or less, more preferably 5 mass% % Or less. When the content of the carboxyl group-containing monomer is less than 15 mass%, the carboxyl group of the carboxyl group-containing monomer does not interfere with the reaction of the reactive group of the crosslinking agent (C) with the reactive group of the cyclic molecule of the polyrotaxane compound (B) An increase in the haze value by the crosslinked product of the taxane compound (B) is sufficiently ensured.

When the (meth) acrylic acid ester polymer (A) contains a monomer having a carboxyl group as a monomer unit constituting the polymer, the content thereof is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, More preferably at least 1.0% by mass. When the content of the carboxyl group-containing monomer is 0.1% by mass or more, the crosslinking structure described above is formed in the pressure-sensitive adhesive, and the pressure-sensitive adhesive maintains the stress relaxation property and the cohesive force is excellent.

The (meth) acrylic acid ester polymer (A) preferably contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer, and thereby can exhibit favorable tackiness have. The alkyl group may be linear or branched or may have a cyclic structure.

Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl Stearyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and adamantyl (meth) acrylate. These may be used alone or in combination of two or more.

Among the above, it is preferable that the (meth) acrylic acid ester polymer (A) contains a (meth) acrylic acid alkyl ester having 5 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer. By including the (meth) acrylic acid alkyl ester having a large number of carbon atoms as a constituent monomer unit, the hydrophobicity of the (meth) acrylic acid ester polymer (A) becomes high and compatibility with the crosslinking agent adduct of the polyrotaxane compound (B) And the haze value of the resulting pressure-sensitive adhesive is further improved.

Among the (meth) acrylic acid alkyl esters having an alkyl group of 5 to 20 carbon atoms, a monomer (hard monomer) having a glass transition temperature (Tg) of more than 0 캜 as a homopolymer and a glass transition temperature (Tg) It is preferable to use a combination of monomers (soft monomer) of 0 占 폚 or lower. This is because, by securing tackiness and flexibility with a soft monomer and improving the cohesive force with a hard monomer, it is possible to further improve the step traceability under high temperature and high humidity conditions. In this case, the mass ratio of the hard monomer to the soft monomer is preferably 5:95 to 40:60, and particularly preferably 20:80 to 30:70.

As the hard monomer, a (meth) acrylic acid alkyl ester having an alicyclic structure in the molecule is preferable, and a (meth) acrylic acid alkyl ester having a plurality of alicyclic structures is more preferable. Examples thereof include isobornyl acrylate (Tg 94 ° C), isobornyl methacrylate (Tg 180 ° C), adamantyl acrylate (Tg 115 ° C), and adamantyl methacrylate (Tg 141 ° C) have. Of the hard monomers, isobornyl acrylate is preferred from the standpoint of exhibiting the performance of hard monomers while preventing adverse effects on other properties such as tackiness.

As the soft monomer, a (meth) acrylic acid alkyl ester having a straight chain or branched chain alkyl group is preferably used. Specifically, 2-ethylhexyl acrylate (Tg -70 ° C) is particularly preferred. That is, as a combination of a hard monomer and a soft monomer, a combination of isobornyl acrylate and 2-ethylhexyl acrylate is particularly preferable.

The (meth) acrylic acid ester polymer (A) preferably contains 30 mass% or more of a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer, more preferably 50 mass% , Particularly preferably 80% by mass or more. When the (meth) acrylic acid alkyl ester is contained in an amount of 30 mass% or more, the (meth) acrylic acid ester polymer (A) can exhibit favorable tackiness. The (meth) acrylic acid ester polymer (A) preferably contains, as monomer units constituting the polymer, 99 mass% or less of a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, Or less, and more preferably 96 mass% or less. By making the amount of the (meth) acrylic acid alkyl ester 99 mass% or less, it is possible to introduce other monomer components into the (meth) acrylic acid ester polymer (A).

The (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group preferably contains a (meth) acrylic acid alkyl ester having 5 to 20 carbon atoms in the alkyl group. (Meth) acrylic acid alkyl ester in which the alkyl group has 5 to 20 carbon atoms and the alkyl group has 1 to 20 carbon atoms in the (meth) acrylic acid alkyl ester, The content of the ester is preferably 5% by mass or more, particularly preferably 20% by mass or more, and more preferably 40% by mass or more. As a result, the above-mentioned haze value improving effect is exerted well together with the stickiness. On the other hand, the content is preferably 100 mass% or less, particularly preferably 95 mass% or less, and more preferably 70 mass% or less. When the content is 95% by mass or less, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms can be contained. This makes it possible to impart hardness to the (meth) acrylic acid ester polymer (A) or fine adjustment of the hydrophobic property. In particular, when only the above-mentioned soft monomer is used as the (meth) acrylic acid alkyl ester having an alkyl group having 5 to 20 carbon atoms, it is preferable to coexist the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms.

The (meth) acrylic acid ester polymer (A) may contain other monomers as monomer units constituting the polymer, if desired. As other monomers, monomers which do not contain reactive functional groups are preferable in order not to inhibit the action of the hydroxyl group-containing monomers and the carboxyl group-containing monomers described above. Examples of the monomer that does not contain a functional group having such a reactive group include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl, ethoxyethyl (meth) acrylate, and vinyl acetate. These may be used alone or in combination of two or more.

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

The upper limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably less than 1.5 million, more preferably 1.3 million or less, and most preferably 90,000 or less. If the upper limit of the weight average molecular weight is as described above, the flexibility of the resulting pressure-sensitive adhesive can be satisfactorily secured, and the step-wise followability can be further improved. The weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 300,000 or more as the lower limit value, particularly preferably 400,000 or more, more preferably 500,000 or more. If the lower limit value of the weight average molecular weight is the above value, the cohesive force of the obtained pressure sensitive adhesive can be maintained favorably, and the step following property under high temperature and high humidity conditions can be further improved. Here, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

In the adhesive composition P, the (meth) acrylic acid ester polymer (A) may be used singly or in combination of two or more kinds.

The content of the (meth) acrylic acid ester polymer (A) in the sticky composition P according to the present embodiment is preferably 60% by mass or more, particularly preferably 70% by mass or more, and more preferably 80% desirable. When the lower limit of the content of the (meth) acrylic acid ester polymer (A) is as described above, the adhesive force of the obtained pressure sensitive adhesive becomes good. The upper limit of the content of the (meth) acrylic acid ester polymer (A) is preferably 99 mass% or less, particularly preferably 98 mass% or less, and more preferably 95 mass% or less. The content of the polyrotaxane compound (B) and the crosslinking agent (C) can be secured by the above-mentioned upper limit of the content of the (meth) acrylic acid ester polymer (A), whereby the haze value of the obtained pressure sensitive adhesive can be effectively improved.

(1-2) Polyrotaxane compound (B)

The polyrotaxane compound (B) is a compound comprising at least two cyclic molecules through which linear molecules penetrate into the openings, and having a block group at both ends of the linear molecule. In this polyrotaxane compound (B), it is possible for the cyclic molecule to move freely in the linear molecular phase, but the cyclic molecule can not be extracted from the linear molecule by the block group. That is, the straight-chain molecule and the cyclic molecule are not chemical bonds such as covalent bonds, but retain their shape by so-called mechanical bonding.

The polyrotaxane compound (B) in the present embodiment preferably has a cyclic molecule containing a reactive group. As described above, when the adhesive composition P is crosslinked, the reactive group of the cyclic molecule of the polyrotaxane compound (B) reacts with the reactive group of the crosslinking agent (C) and the compatibility with the (meth) acrylic acid ester polymer (A) This low crosslinking adduct is formed. The haze value of the resulting pressure-sensitive adhesive is increased by the crosslinking agent addition product. Further, the crosslinking agent addition product crosslinks the (meth) acrylic acid ester polymer (A) having a hydroxyl group or a carboxyl group with each other. The crosslinking agent to be added to the crosslinking agent has flexibility in the crosslinking structure of the (meth) acrylic acid ester polymer (A) by allowing each cyclic molecule of the polyrotaxane compound (B) to freely move in the linear molecular phase The resulting pressure-sensitive adhesive exhibits a high cohesive force and a high stress relaxation property, and is excellent in step-wise followability.

The reactive group of the cyclic molecule of the polyrotaxane compound (B) is not particularly limited as long as it can react with the reactive group of the cross-linking agent (C), and examples thereof include a hydroxyl group and a carboxyl group. Among them, a hydroxyl group is preferable .

The polyrotaxane compound (B) in the present embodiment preferably has a cyclic oligosaccharide as a cyclic molecule. The cyclic oligosaccharide has a hydroxyl group as a reactive group in an unmodified state. In addition, by using the cyclic oligosaccharide as the cyclic molecule of the polyrotaxane compound (B), it becomes possible to select an appropriate ring diameter, thereby manifesting the effect of moving the cyclic molecule on the linear molecule easy. In addition, it is possible to easily introduce various substituents and the like, thereby making it possible to adjust the physical properties of the resulting pressure-sensitive adhesive. In addition, cyclic oligosaccharides are advantageous in that they are easily available. In the present specification, the "cyclic molecule" of "cyclic molecule" or "cyclic oligosaccharide" means substantially "cyclic". That is, if it is movable on a linear molecule, the cyclic molecule may not be completely ring closed, but may be, for example, a helical structure.

As the cyclic oligosaccharide, cyclodextrins such as? -Cyclodextrin,? -Cyclodextrin and? -Cyclodextrin are preferably used, and among them,? -Cyclodextrin is particularly preferable. The cyclic molecule of the polyrotaxane compound (B) may be contained in the polyrotaxane compound (B) or in the adhesive composition P in combination.

The hydroxyl group possessed by the cyclic oligosaccharide as a reactive group may be a hydroxyl group having a cyclic oligosaccharide in an original (state before modification), or a hydroxyl group as a substituent in a cyclic oligosaccharide.

The lower limit of the hydroxyl value of the cyclic molecule is preferably 10 mgKOH / g or more, more preferably 30 mgKOH / g or more, and particularly preferably 50 mgKOH / g or more. If the lower limit of the hydroxyl value is above, the polyrotaxane compound (B) can sufficiently react with the crosslinking agent (C). The upper limit of the hydroxyl value of the cyclic molecule is preferably 1000 mgKOH / g or less, more preferably 200 mgKOH / g or less, and particularly preferably 100 mgKOH / g or less. When the upper limit value of the hydroxyl value exceeds the above value, a large number of crosslinks occur in the same cyclic molecule, whereby the cyclic molecule itself becomes a crosslinking point, and the effect of crosslinking point as the whole polyrotaxane compound (B) As a result, there is a possibility that sufficient flexibility can not be ensured in the resulting pressure-sensitive adhesive.

The straight-chain molecule of the polyrotaxane compound (B) is a molecule or substance which is embedded in a cyclic molecule and can be integrated by a mechanical bond rather than a chemical bond such as a covalent bond, and is not particularly limited as long as it is a straight chain. In the present specification, the term "linear chain" of "linear molecule" means substantially "linear chain". That is, when the cyclic molecule is movable on the linear molecule, the linear molecule may have a branched chain.

The linear molecule of the polyrotaxane compound (B) includes, for example, polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylic acid ester, polydimethylsiloxane, polyethylene, Polypropylene and the like are preferable, and these linear molecules may be mixed in two or more kinds among the adhesive composition P.

The number average molecular weight of the straight chain molecule of the polyrotaxane compound (B) is preferably 3,000 or more as the lower limit value, particularly preferably 10,000 or more, and more preferably 20,000 or more. If the lower limit of the number average molecular weight is the above range, the amount of cyclic molecules moving on the linear molecule is secured, and the flexibility of the crosslinked structure attributable to the polyrotaxane compound (B) is sufficiently obtained. The upper limit of the number average molecular weight of the straight chain molecule of the polyrotaxane compound (B) is preferably 300,000 or less, more preferably 200,000 or less, and even more preferably 100,000 or less. If the upper limit of the number average molecular weight is above, the solubility of the polyrotaxane compound (B) in a solvent becomes good.

The block group of the polyrotaxane compound (B) is not particularly limited as long as it is a group in which the cyclic molecule can maintain a form in which the linear molecule forms a skeleton. Examples of such groups include a bulky group and an ionic group.

Specifically, the blocking group of the polyrotaxane compound (B) is preferably a block copolymer of a dinitrophenyl group, a cyclodextrin group, an adamantane group, a trityl group, a fluorescein, a pyrene, an anthracene, And the like. The block group may be contained in the polyrotaxane compound (B) or in the adhesive composition P in combination of two or more.

The polyrotaxane compound (B) described above can be obtained by a conventionally known method (for example, a method described in Japanese Patent Application Laid-Open No. 2005-154675).

The content of the polyrotaxane compound (B) in the adhesive composition P according to the present embodiment is preferably 1 part by mass or more as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A) Or more, and more preferably 5 parts by mass or more. If the lower limit of the content of the polyrotaxane compound (B) is above, the haze value of the resulting pressure-sensitive adhesive can be satisfactorily improved. The upper limit of the content of the polyrotaxane compound (B) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, particularly preferably 20 parts by mass or less. If the upper limit of the content of the polyrotaxane compound (B) is above, the adhesive force of the obtained pressure sensitive adhesive can be made sufficient.

(1-3) Crosslinking agent (C)

The crosslinking agent (C) has a reactive group. This reactive group may be any one capable of reacting with a hydroxyl group or a carboxy group of the (meth) acrylic acid ester polymer (A) and a reactive group of a cyclic molecule of the polyrotaxane compound (B). Such a crosslinking agent (C) forms a crosslinking agent addition product with the polyrotaxane compound (B). Further, the crosslinking agent addition product crosslinks the (meth) acrylic acid ester polymer (A).

Examples of the reactive group of the crosslinking agent (C) include an isocyanate group, an epoxy group, an amino group, a vinylsulfone group and an organic metal. Examples of the crosslinking agent (C) having such a reactive group include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, vinyl sulfone crosslinking agents and organic titanium zirconium compounds. Of these, isocyanate-based crosslinking agents having high reactivity with hydroxyl groups are preferable. According to the isocyanate-based crosslinking agent, the crosslinking agent addition of the polyrotaxane compound (B) having a hydroxyl group as a reactive group can be sufficiently carried out, whereby the haze value of the obtained pressure-sensitive adhesive can be effectively increased. The crosslinking agent (C) may be used singly or in combination of two or more kinds.

The isocyanate crosslinking agent includes at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane di An alicyclic polyisocyanate such as isocyanate and the like, and an adduct which is a reaction product of a burette, isocyanurate and a low molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylol propane, And the like. Among them, trimethylolpropane-modified aromatic polyisocyanate, trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are particularly preferable from the viewpoint of reactivity with a hydroxyl group.

When the (meth) acrylic acid ester polymer (A) contains a monomer containing a hydroxyl group as a monomer unit constituting the polymer and contains a monomer containing a carboxyl group, an epoxy (meth) acrylate polymer having high reactivity with a carboxyl group It is also preferable to use a cross-linking agent.

Examples of the epoxy-based crosslinking agent include 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl- Ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylol propane diglycidyl ether, diglycidyl aniline, diglycidyl amine, and the like. Among them, N, N, N ', N'-tetraglycidyl-m-xylylenediamine is preferable from the viewpoint of reactivity with a carboxy group.

The content of the crosslinking agent (C) in the sticky composition P is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A) Or more. If the lower limit of the content of the crosslinking agent (C) is above, the crosslinking agent adduct of the polyrotaxane compound (B) described above can be satisfactorily formed, and the haze value of the resulting pressure-sensitive adhesive can be effectively improved. The content of the crosslinking agent (C) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and most preferably 20 parts by mass or less, based on 100 parts by mass of the (meth) acrylic acid ester polymer (A) desirable. When the upper limit of the content of the cross-linking agent (C) is above, the degree of cross-linking is suitably determined, and thus it is possible to ensure satisfactory step traceability of the obtained pressure-sensitive adhesive. From the viewpoint of better step traceability, the upper limit value of the cross-linking agent (C) is more preferably 14 parts by mass or less, particularly preferably 6 parts by mass or less.

(1-4) Various additives

The pressure-sensitive adhesive composition P may contain various additives usually used in acrylic pressure-sensitive adhesives, such as a silane coupling agent, an ultraviolet absorber, an antistatic agent, a tackifier, an antioxidant, a light stabilizer, a softening agent, a refractive index- can do. It is also assumed that the polymerization solvent or diluting solvent to be described later is not included in the additive constituting the adhesive composition P.

On the other hand, the sticky composition P preferably does not contain a filler such as fine particles. According to the pressure-sensitive adhesive Q, a high haze value can be obtained even if fine particles are not used. If the filler is not contained, it is not necessary to use dedicated piping or a dedicated kiln, and there is no risk of contamination to other products that do not contain a filler. In addition, since the filler as the raw material also requires no work of dispersing the filler in the pressure-sensitive adhesive, it is possible to reduce the cost.

(2) Preparation of sticky composition

The sticky composition P is obtained by preparing the (meth) acrylic acid ester polymer (A), mixing the obtained (meth) acrylic acid ester polymer (A), the polyrotaxane compound (B) and the cross- And adding an additive in accordance with the present invention.

The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a conventional radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) is preferably carried out by a solution polymerization method using a polymerization initiator if desired. As the polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like may be used.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more of them may be used in combination. Examples of the azo compound include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane 1-carbonyl Azobis (2,4-dimethyl-4-methoxy valeronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) Azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile) Azobis [2- (2-imidazolin-2-yl) propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate , t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

In the polymerization step, a weight average molecular weight of the obtained polymer can be controlled by blending a chain transfer agent such as 2-mercaptoethanol.

(A), a polyrotaxane compound (B), a crosslinking agent (C) and, if desired, a diluting solvent and an additive are added to the solution of the (meth) acrylic acid ester polymer (A) , And sufficiently mixed to obtain a viscous composition P (coating solution) diluted with a solvent. In the case where precipitation occurs when any one of the above components is used in a solid phase or when it is mixed with other components in a non-diluted state, the component is dissolved or diluted in advance in a diluting solvent , And then mixed with other components.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, Propanol and the like; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone; esters such as ethyl acetate and butyl acetate; and cellosolve solvents such as ethyl cellosolve Is used.

The concentration and viscosity of the coating solution prepared as described above may be appropriately selected depending on the circumstances without limitation, as long as the coating can be performed within a range that can be coated. For example, it is diluted such that the concentration of the sticky composition P is 10 to 60 mass%. In order to obtain the coating solution, the addition of a diluting solvent and the like is not a necessary condition, and a diluting solvent may not be added if the viscosity of the adhesive composition P is such as to be a coating. In this case, the adhesive composition P is a coating solution containing a polymerization solvent of the (meth) acrylic acid ester polymer (A) as it is as a diluting solvent.

(3) Production of pressure-sensitive adhesive

By cross-linking the adhesive composition P, a pressure-sensitive adhesive Q is obtained. The crosslinking of the adhesive composition P can be usually carried out by a heat treatment. This heating treatment may also serve as a drying treatment for volatilizing a diluting solvent or the like from a coating film of the sticky composition P applied to a desired object.

The heating temperature for the heat treatment is preferably 50 to 150 占 폚, particularly preferably 70 to 120 占 폚. The heating time is preferably 10 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes.

After the heat treatment, a curing period of about 1 to 2 weeks may be provided at room temperature (for example, at 23 DEG C and 50% RH), if necessary. When the curing period is necessary, after the curing period, when the curing period is unnecessary, the pressure-sensitive adhesive Q is formed after the heat treatment is finished.

At least the polyrotaxane compound (B) and, optionally, the (meth) acrylic acid ester polymer (A) are also crosslinked by the above heat treatment (and curing) through the crosslinking agent (C). The pressure-sensitive adhesive Q thus obtained is capable of suppressing the generation of moire in the display body, and is also excellent in step-wise followability.

(4) Thickness of the pressure-sensitive adhesive layer

The thickness (the value measured in accordance with JIS K7130) of the pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheet 1 according to the present embodiment is preferably 10 占 퐉 or more as the lower limit value, more preferably 25 占 퐉 or more, Mu] m or more. If the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is the above-mentioned value, the desired adhesive force is easily exerted, and satisfactory step traceability can be ensured with respect to the normal step of the display body constituting member.

The upper limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 1000 占 퐉 or less, more preferably 500 占 퐉 or less, and particularly preferably 300 占 퐉 or less. If the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is above, the workability becomes good. The pressure-sensitive adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

2-2. Peeling sheet

The release sheets 12a and 12b protect the pressure-sensitive adhesive layer 11 by the use of the pressure-sensitive adhesive sheet 1 and are peeled off when the pressure-sensitive adhesive sheet 1 (pressure-sensitive adhesive layer 11) is used. In the pressure-sensitive adhesive sheet 1 according to the present embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

Examples of the release sheets 12a and 12b include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, (Meth) acrylic acid copolymer film, an ethylene / (meth) acrylic acid ester copolymer film, a polystyrene film, a poly (ethylene terephthalate) film, a polybutylene terephthalate film, a polyurethane film, an ethylene vinyl acetate film, an ionomer resin film, A carbon film, a polyimide film, a fluororesin film, or the like is used. These crosslinked films are also used. Further, these laminated films may be used.

It is preferable that a peeling treatment is performed on the peeling surface of the peeling sheets 12a and 12b (in particular, the surface in contact with the peeling layer 11). Examples of the releasing agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based releasing agents. It is also preferable that one of the release sheets 12a and 12b is a heavy-duty release sheet having a large stripping force and the other release sheet is a light-leakage release sheet having a small stripping force.

The thickness of the release sheets 12a, 12b is not particularly limited, but is usually about 20 to 150 mu m.

3. Production of adhesive sheet

As one production example of the adhesive sheet 1, the application liquid of the adhesive composition P is applied to the release surface of one release sheet 12a (or 12b) and heat-treated to thermally crosslink the adhesive composition P, After the layer is formed, the peeling surface of the other peeling sheet 12b (or 12a) is superposed on the coated layer. When the curing period is required, the curing period is set so that the coating layer becomes the pressure-sensitive adhesive layer 11 when the curing period is unnecessary. Thus, the pressure-sensitive adhesive sheet (1) is obtained. The conditions of the heat treatment and curing are as described above.

As another production example of the adhesive sheet 1, the application liquid of the adhesive composition P is applied to the release surface of one release sheet 12a and heat-treated to thermally crosslink the adhesive composition P to form a coating layer , A release sheet 12a with a coating layer is obtained. The application liquid of the adhesive composition P is applied to the release surface of the other release sheet 12b and heat-treated to thermally crosslink the adhesive composition P to form a release layer, (12b). Then, the peeling sheet 12a with a coating layer and the peeling sheet 12b with a coating layer are bonded so that both coating layers are in contact with each other. When the curing period is required, the curing period is provided, and when the curing period is unnecessary, the above-mentioned laminated coating layer becomes the pressure-sensitive adhesive layer (11). Thus, the pressure-sensitive adhesive sheet (1) is obtained. According to this manufacturing method, even if the pressure-sensitive adhesive layer 11 is thick, it can be manufactured stably.

As a method of applying the application liquid of the sticky composition P, for example, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, a gravure coat method and the like can be used.

[Display]

Fig. 2 shows an example of a display body obtained by using the pressure-sensitive adhesive sheet 1 according to the present embodiment. The display body 2 according to the present embodiment includes a first display body constituting member 21 (one display body constituting member) and a second display body constituting member 22 (Another display member constituting member) and a pressure-sensitive adhesive layer 11 interposed between the first display body constituting member 21 and the second display body constituting member 22 to each other. In the display body 2 according to the present embodiment, the first display body constituting member 21 has a step on the surface of the pressure-sensitive adhesive layer 11 side, specifically, I have.

The pressure sensitive adhesive layer 11 in the display body 2 is the pressure sensitive adhesive layer 11 of the pressure sensitive adhesive sheet 1 described above.

As the display body 2, for example, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, an electronic paper and the like may be mentioned. The display body 2 may be a member constituting a part of them.

It is preferable that the first display body constituting member 21 is a protective panel made of a glass plate, a plastic plate, etc., as well as a laminate including them. In this case, the print layer 3 is generally formed on the side of the pressure-sensitive adhesive layer 11 of the first display body constituting member 21 in a framed frame.

The glass plate is not particularly limited and includes, for example, chemically strengthened glass, non-alkali glass, quartz glass, soda lime glass, barium-strontium glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, . The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

In addition, various functional layers (a transparent conductive film, a metal layer, a silica layer, a hard coat layer, an antiglare layer, or the like) may be provided on one or both sides of the glass plate or the plastic plate, or optical members may be laminated. The transparent conductive film and the metal layer may be patterned.

The second display body constituting member 22 includes an optical member to be attached to the first display body constituting member 21, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) Luminescent (organic EL) module or the like), an optical member as a part of the display body module, or a display body module.

Examples of the optical member include a light-scattering film, a polarizing plate (polarizing film), a polarizer, a retardation film (phase difference film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, A film, and a transparent conductive film. Examples of the shake-prevention film include a hard coat film formed by forming a hard coat layer on one side of a base film.

The material constituting the print layer 3 is not particularly limited, and known materials for printing are used. The thickness of the printing layer 3, that is, the lower limit of the height of the stepped portion is preferably 3 mu m or more, more preferably 5 mu m or more, particularly preferably 7 mu m or more, most preferably 10 mu m or more. With the above-described lower limit value, it is possible to sufficiently secure concealment such as disabling the electric wiring from being visible from the viewer side. The upper limit value is preferably 50 탆 or less, more preferably 35 탆 or less, particularly preferably 25 탆 or less, and more preferably 20 탆 or less. The upper limit value is set as described above, so that the step following property of the pressure-sensitive adhesive layer 11 with respect to the printing layer 3 can be prevented from deteriorating.

In order to manufacture the display body 2, for example, one of the release sheets 12a of the pressure-sensitive adhesive sheet 1 is peeled off, and the exposed pressure-sensitive adhesive layer 11 of the pressure- To the side of the constituent member 21 on which the print layer 3 is present. At this time, since the pressure-sensitive adhesive layer 11 is excellent in step-following ability, it is possible to suppress the occurrence of a gap or lifting in the vicinity of the stepped portion by the printed layer 3.

The other release sheet 12b is peeled off from the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 and the pressure-sensitive adhesive layer 11 and the second display member constituting member 22, . As another example, the order of combining the first display body constituent member 21 and the second display body constituent member 22 may be changed.

In the display body 2, since the occurrence of moiré is suppressed by the pressure-sensitive adhesive layer 11, the visibility as a display is excellent. Since the pressure sensitive adhesive layer 11 of the display body 2 is excellent in step traceability under high temperature and high humidity conditions, the display body 2 can be prevented from being deformed under high temperature and high humidity conditions (for example, 85% RH), generation of bubbles, lifting, peeling, and the like in the vicinity of the step is suppressed.

The position of use of the pressure-sensitive adhesive sheet 1 (pressure-sensitive adhesive layer 11) according to the present embodiment in the display body is not limited to the above example. For example, the pressure-sensitive adhesive sheet 1 according to the present embodiment may be used for bonding display member constituting members having no such step. Specifically, the pressure-sensitive adhesive sheet 1 according to the present embodiment is also suitably used for bonding a liquid crystal cell and a backlight. The resulting display body is excellent in visibility as a display because the occurrence of moiré is suppressed by the pressure-sensitive adhesive layer (11). Further, due to the excellent flexibility of the pressure-sensitive adhesive layer 11, adhesion with high durability can be expected flexibly corresponding to elongation and contraction of the optical member due to cold difference (cold difference).

The embodiments described above are described for the purpose of facilitating understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents falling within the technical scope of the present invention.

For example, one or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted, or a desired optical member may be laminated instead of the release sheets 12a and / or 12b. Further, the first display body constituting member 21 may have a step difference other than the print layer 3. In addition to the first display body constituting member 21, the second display body constituting member 22 may also have a step on the pressure-sensitive adhesive layer 11 side.

(Example)

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]

1. Preparation of (meth) acrylic acid ester polymer

47.5 parts by mass of n-butyl acrylate, 47 parts by mass of 2-ethylhexyl acrylate, 5 parts by mass of acrylic acid and 0.5 parts by mass of 2-hydroxyethyl acrylate were copolymerized by solution polymerization to prepare a (meth) acrylic acid ester polymer (A) did. The molecular weight of the (meth) acrylic acid ester polymer (A) was measured by a method described later, and the weight average molecular weight (Mw) was 70,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylic acid ester polymer (A) obtained in the above Step 1 (solid content conversion value: the same hereinafter) and the polyrotaxane compound (B) (trade name: SILM SUPER POLYMERS SH3407P Cyclic dextrin having a hydroxyl group and caprolactone chain, block group: adamantane, weight average molecular weight (Mw) of 700,000, and hydroxyl group of 72 mgKOH / g) 5.0 mass% And 2.0 parts by mass of trimethylolpropane-modified tolylene diisocyanate (Nippon Polyurethanes, product name: Coronate L) as a crosslinking agent (C) were mixed, sufficiently stirred and diluted with methyl ethyl ketone, Solution.

Table 1 shows the respective blend (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester polymer (A) was changed to 100 parts by mass (solid content conversion value). Details of the abbreviations, etc. shown in Table 1 are as follows.

[(Meth) acrylic acid ester polymer (A)]

BA: n-butyl acrylate

2EHA: 2-ethylhexyl acrylate

AA: Acrylic acid

HEA: 2-hydroxyethyl acrylate

IBXA: isobornyl acrylate

[Crosslinking agent (C)]

TDI: trimethylolpropane-modified tolylene diisocyanate (Nippon Polyurethanes, product name: Coronate L)

XDI: trimethylolpropane-modified xylylene diisocyanate (product name "TD-75" manufactured by Soken Chemical & Engineering Co., Ltd.)

Epoxy: N, N, N ', N'-tetraglycidyl-m-xylylenediamine (product name: "E-AX"

[Particulate matter]

(Momentive Performance Materials, Japan Sansei, trade name: TOSHAL 145, average particle size: 4.5 mu m, refractive index: 1.42) comprising a silicon-containing compound having an intermediate structure of inorganic and organic components,

3. Production of adhesive sheet

(1) Production of first pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 25 m)

The coating solution of the sticky composition obtained in the above Step 2 was coated on a release treatment surface of a heavy-duty release sheet (LINTEC Corporation, product name " SP-PET752150 ") in which one side of the polyethylene terephthalate film was stripped with a silicone- did. Then, the coating layer was heat-treated at 90 DEG C for 1 minute to form a coating layer.

Next, the coating layer on the heavy-duty release sheet obtained above and a light-weight receding release sheet (LINTEC SHAZE, product name " SP-PET382120 ") in which one side of the polyethylene terephthalate film was stripped with a silicone- Was peeled off at a temperature of 23 占 폚 under a condition of 50% RH for 7 days to prepare a pressure-sensitive adhesive sheet having a configuration of a heavy-duty release sheet / pressure-sensitive adhesive layer / light- The thickness of the pressure-sensitive adhesive layer in this pressure-sensitive adhesive sheet was 25 탆. This pressure sensitive adhesive sheet is referred to as a first pressure sensitive adhesive sheet.

(2) Production of second pressure-sensitive adhesive sheet (thickness of pressure-sensitive adhesive layer: 50 m)

The coating solution of the sticky composition obtained in the above Step 2 was coated on a release treatment surface of a heavy-duty release sheet (LINTEC Corporation, product name " SP-PET752150 ") in which one side of the polyethylene terephthalate film was stripped with a silicone- did. Then, the coating layer was heat-treated at 90 DEG C for 1 minute to form a coating layer. Likewise, the coating solution of the obtained sticky composition was applied to the release treatment surface of a lightly peelable release sheet (LINTEC SHAZETE, product name " PET382120 ") in which one side of the polyethylene terephthalate film was peeled off with a silicone- Coated with a knife coater, and then heat-treated at 90 DEG C for 1 minute to form a coated layer.

Next, the above heavy-leaved release sheet with a coating layer and the above-obtained light-leaved release sheet with a coating layer obtained as described above were bonded to each other so as to be in contact with each other, Curing was carried out to prepare a pressure-sensitive adhesive sheet having a configuration of a heavy-duty releasing sheet / pressure-sensitive adhesive layer / light-duty releasing sheet. The thickness of the pressure-sensitive adhesive layer in this pressure-sensitive adhesive sheet was 50 탆. This pressure sensitive adhesive sheet is referred to as a second pressure sensitive adhesive sheet.

The thickness of the pressure-sensitive adhesive layer is a value measured using a constant pressure thickness gauge (trade name: " PG-02 ") according to JIS K7130.

[Examples 2 to 21 and Comparative Examples 1 to 7]

(A), the kind and ratio of each monomer constituting the (meth) acrylic acid ester polymer (A), the weight average molecular weight of the (meth) acrylic acid ester polymer (A), the blending amount of the polyrotaxane compound (B) And the blending amount were changed as shown in Table 1, the first and second adhesive sheets were produced in the same manner as in Example 1.

In the adhesive composition of Comparative Example 6, fine particles (microparticles made of a silicon-containing compound having an intermediate structure of inorganic and organic; Momentive Performance Materials Japan Shuze, trade name: TOSHAL 145, average particle diameter: 4.5 탆, refractive index: 1.42) was added in an amount of 7.0 parts by mass.

Here, the weight average molecular weight (Mw) described above is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement Conditions>

GPC measurement apparatus: Tosoh Co., Ltd., HLC-8020

· GPC column (pass in the following order): Dososaje

  TSK guard column HXL-H

  TSK gel GMHXL (× 2)

  TSK gel G2000HXL

Measurement solvent: tetrahydrofuran

· Measuring temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

The first pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 25 占 퐉) obtained in Examples and Comparative Examples was cut into a size of 80 mm 占 80 mm and the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200) Was weighed with a precision balance and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is defined as M1.

Next, the adhesive wrapped with the polyester-made mesh was immersed in ethyl acetate at room temperature (23 DEG C) for 24 hours. Thereafter, the pressure-sensitive adhesive was taken out and air-dried for 24 hours under an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M2. The gel fraction (%) is represented by (M2 / M1) x100. The results are shown in Table 2.

[Test Example 2] (Measurement of haze value)

("NDH-2000" manufactured by Nippon Denshoku Chemical Co., Ltd.) in accordance with JIS K7136: 2000 was applied to the pressure-sensitive adhesive layer of the first pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: Was used to measure the haze value (%). The results are shown in Table 2.

[Test Example 3] (Measurement of total light transmittance)

The pressure-sensitive adhesive layer of the first pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 25 占 퐉) obtained in the examples and the comparative example was measured for haze meter (product name: "NDH-2000 ) Was used to measure the total light transmittance (%). The results are shown in Table 2.

[Test Example 4] (Measurement of adhesive force)

The lightly curled release sheet was peeled off from the first pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 25 占 퐉) obtained in the examples and the comparative examples and the exposed pressure-sensitive adhesive layer was coated with polyethylene terephthalate (PET) Was laminated on this adhesive layer of a film (Toyobo Co., Ltd., product name &quot; PET A4300 &quot;, thickness: 100 mu m) to obtain a laminate of release sheet / pressure-sensitive adhesive layer / PET film. The obtained laminate was cut into 25 mm width and 100 mm length, and this was used as a sample.

The peelable release sheet was peeled off from the sample under the environment of 23 占 폚 and 50% RH, and the exposed pressure-sensitive adhesive layer was stuck to soda lime glass (Nihon Itagarasusha), followed by autoclave of Kurihara Seisaku Josha Co. MPa, at 50 DEG C for 20 minutes. (N / 25) at a peeling speed of 300 mm / min and a peeling angle of 180 degrees using a tensile tester (Orientech Corp., Tensilon) after leaving for 24 hours under the conditions of 23 deg. Mm) was measured. Conditions other than those described herein were measured in accordance with JIS Z 0237: 2009. The results are shown in Table 2.

[Test Example 5] (Evaluation of Step Followability)

(Trade name: POS-911 JUKI) was coated on the surface of a glass plate (NSG Precision Shaware, product name: Corning Glass Eagle XG, length 90 mm x width 50 mm x thickness 0.5 mm) Screen printing was performed on the rim (outer shape: length 90 mm x width 50 mm, width 5 mm). Next, the printed ultraviolet curable ink was cured by irradiating ultraviolet rays (80 W / cm 2, metal halide lamp 2, lamp height 15 cm, belt speed 10 to 15 m / min) : 5 占 퐉, 10 占 퐉, 15 占 퐉, 20 占 퐉).

The lightly recyclable release sheet was peeled off from the second pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 50 占 퐉) obtained in Examples and Comparative Examples and the exposed pressure-sensitive adhesive layer was laminated on a polyethylene terephthalate film (Toyobo Co., A4300 &quot;, thickness: 100 mu m). Next, the heavy-duty release sheet was peeled off, and a pressure-sensitive adhesive layer was exposed. Then, the laminate was laminated on each stepped glass plate so that the pressure-sensitive adhesive layer covered the front surface of the frame on the framed frame by using a laminator (Fujifrica, product name: &quot; LPD3214 &quot;).

The obtained evaluation sample was subjected to autoclave treatment at 50 캜 under 0.5 MPa for 30 minutes and then left at normal pressure, 23 캜, and 50% RH for 24 hours. Next, the sample was stored for 72 hours under a moist heat condition of 85 캜 and 85% RH (endurance test), and then the step traceability was evaluated. It is judged whether or not the printing step is completely filled by the pressure-sensitive adhesive layer, and it is judged that the step following property can not follow the printing step if gaps or bubbles are observed at the interface between the printing step and the pressure-sensitive adhesive layer . Here, the step following ability was evaluated as a step following rate (%) according to the following criteria. The results are shown in Table 2.

(%) = {(Height of printed stepped without gap or bubble (mu m) / (thickness of pressure-sensitive adhesive layer: 50 m)} x 100

◎: Step following rate 40%

○: step following rate 30%

△: Follow rate of steps 20%

X: step following rate 10% or less

Test Example 6 (Evaluation of suppression of moire occurrence)

The surface of the copper foil of a copper-clad laminate (Nikkochekkusha Co., Ltd., product name "Nikaflex") comprising a copper foil (thickness: 18 탆) and a polyethylene terephthalate film I printed the pattern. Thereafter, unnecessary copper foil was removed by etching to obtain a transparent conductive film in which a plurality of parallel lines having a line width of 100 mu m and a gap of 100 mu m between lines were patterned.

Two transparent conductive films thus obtained were laminated through the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples so that the lines were orthogonal to each other, and this was used as an evaluation sample.

The above evaluation sample was displayed on a display screen of a tablet terminal (product name "iPad (registered trademark)", resolution: 264 ppi) with front green display (RGB value (R, G, B) = 0, 255, And the state of moiré (the degree of suppression of moiré occurrence) was judged by panelists 5. Then, the degree of suppression of moire occurrence was evaluated by the following evaluation criteria. The results are shown in Table 2.

◎: All 5 people judged that the occurrence of moire was suppressed

○: 4 to 3 out of 5 people judged that the occurrence of moire was suppressed

△: 2 to 1 out of 5 people judged that the occurrence of moire was suppressed

×: All five persons judged to be insufficient to inhibit generation of moire

[Test Example 7] (Tensile test)

The pressure-sensitive adhesive layer was formed so that the total thickness of the pressure-sensitive adhesive layers in the second pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer thickness: 50 탆) obtained in Examples and Comparative Examples was 500 탆 and only the release sheet of the outermost layer of the laminate remained A plurality of layers were laminated and left for 24 hours in an atmosphere of 23 ° C and 50% RH. Thereafter, a sample of 10 mm wide × 75 mm long was cut out from the pressure-sensitive adhesive sheet in which a plurality of the pressure-sensitive adhesive layers were laminated, the release sheet laminated on the outermost layer of the laminate was peeled off, (Elongation direction), and elongation was carried out at a tensile rate of 200 mm / min using a tensile tester (Orientech Co., Tensilon) under the environment of 23 ° C and 50% RH to determine the elongation at break Respectively. Further, the stress (fracture stress; N) at the time of fracture was measured, and the value obtained by dividing the fracture stress by the cross-sectional area (5 mm 2) of the sample was calculated as the film strength. The results are shown in Table 2.

[Table 1]

[Table 2]

As can be seen from Table 2, the pressure-sensitive adhesive sheet obtained in the Examples suppressed the generation of moire and was also excellent in step-wise followability.

The pressure-sensitive adhesive sheet of the present invention can be suitably used, for example, in bonding between a protective panel having a step and a desired display body constituting member, or bonding of a liquid crystal cell and a backlight.

1: adhesive sheet 11: pressure-sensitive adhesive layer
12a, 12b: peeling sheet 2: display body
21: first display body constituting member 22: second display body constituting member
3: Printing layer

Claims (5)

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer,
Wherein the pressure-sensitive adhesive layer has a haze value of 30% or more and 95% or less,
The breaking elongation of the pressure-sensitive adhesive layer by a tensile test is 500% or more,
The gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is 20% or more and 95% or less
Wherein the pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet. The method according to claim 1,
Wherein the pressure-sensitive adhesive contains a polyrotaxane compound. The method according to claim 1,
The pressure-
(Meth) acrylic acid ester polymer (A)
The polyrotaxane compound (B)
The crosslinking agent (C)
Sensitive adhesive composition comprising a pressure-sensitive adhesive composition comprising a pressure-
Wherein the pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet. The method according to claim 1,
Wherein the pressure-sensitive adhesive contains no filler. 5. The method according to any one of claims 1 to 4,
Two peeling sheets are provided,
Wherein the pressure-sensitive adhesive layer is sandwiched between the peeling sheets so as to come into contact with the peeling surfaces of the two peeling sheets
Wherein the pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet.

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