KR20130002265A - Adhesive composition, adhesive and adhesive sheet - Google Patents

Abstract

PURPOSE: An adhesive composition is provided to have excellent stress-releasing performance, to prevent light leakage, and to have excellent durability and reworkability when used in an optical unit such as a polarizer. CONSTITUTION: An adhesive composition comprises a first (meth)acrylic acid ester with the weight average molecular weight of 500,000-3,000,000, a second (meth)acrylic ester polymer with the average molecular weight of 8,000-300,000, and a crosslinking agent. Each of the first and second (meth)acrylic ester polymer does not contain an acidic group substantially, and contains a hydroxy group-containing monomer as a monomer unit for composing the polymer. The molar ratio of the hydroxy group in the second (meth)acrylic ester polymer to the hydroxy group in the first (meth)acrylic ester polymer is 1.0-40.

Description

Adhesive composition, adhesive and adhesive sheet {ADHESIVE COMPOSITION, ADHESIVE AND ADHESIVE SHEET}

TECHNICAL FIELD The present invention relates to an adhesive composition, an adhesive (a material obtained by crosslinking an adhesive composition), and an adhesive sheet, and in particular, relates to an adhesive composition, an adhesive, and an adhesive sheet suitable for an optical member such as a polarizing plate.

In general, in a liquid crystal panel, an adhesive layer formed of an adhesive composition is often used to adhere a polarizing plate or a retardation plate to a glass substrate of a liquid crystal cell. However, since optical members such as polarizing plates and retardation plates tend to shrink due to heat and the like, shrinkage occurs due to thermal history, and as a result, the pressure-sensitive adhesive layer laminated on the optical member cannot follow the shrinkage. It has been pointed out that a problem arises in that peeling (so-called lifting, peeling) occurs or light leakage (so-called white hair) caused by the optical axis of the optical member is deviated due to the stress at the time of shrinkage of the optical member.

As a method for preventing this, (1) a method of suppressing shrinkage of the optical member itself by bonding an adhesive layer having a high adhesion and excellent shape stability to an optical member such as a polarizing plate, or (2) shrinking of the optical member The method of using the adhesive layer with small stress at the time is mentioned. As the method of (1), it is effective to use the adhesive layer with high storage elastic modulus, as published in patent document 1. On the other hand, it is effective to use the adhesive layer excellent in the stress relaxation property which can respond flexibly to the deformation | transformation of an optical member as the method of (2).

In order to perform the method of said (2), patent document 2 is a copolymer of (A) alkyl (meth) acrylate and 0.5-20 weight% of polymerizable monomers which have the functionality with respect to a crosslinking agent, and also weight average 100 parts by weight of a high molecular weight (meth) acrylic copolymer having a molecular weight of 1 million or more, (B) 20 to 200 parts by weight of a low molecular weight (meth) acrylic (co) polymer having a weight average molecular weight of 30,000 or less, and (C) a crosslinked structure It consists of 0.005-5 weight part of polyfunctional compounds which have at least 2 functional group in a molecule | numerator, and [functional group of a low molecular weight (meth) acrylic-type (co) polymer] / [functional group of a high molecular weight (meth) acrylic copolymer] The adhesive for polarizing plates in which the functional group distribution ratio displayed exists in the range of 0-15 weight% is proposed.

Similarly, in order to implement the method of said (2), patent document 3 has a weight average molecular weight of 800,000-2 million (meth) acrylic acid ester in all 100 mass parts of polymers (a), and a weight average molecular weight of 50,000 or less (Meth) acrylic acid ester consists of the acrylic acid ester copolymer mixture (A) which consists of 20-100 mass parts of polymers (b), and a crosslinking agent (B), The said copolymer (a) is a functional group with high reactivity with a crosslinking agent (B). Optical adhesive composition which contains the monomeric unit which has a WHEREIN, and the said copolymer (b) contains the monomeric unit which has a functional group less reactive than a functional group of a crosslinking agent (B) and the said copolymer (a) is proposed.

[Patent Document 1] Japanese Patent Laid-Open No. 2006-235568 [Patent Document 2] Patent No. 3533589 [Patent Document 3] Japanese Patent Laid-Open No. 2009-108122

The pressure-sensitive adhesive disclosed in Patent Literatures 2 and 3 is intended to obtain stress relaxation property by preferentially crosslinking a high molecular weight (meth) acrylic copolymer. However, such an adhesive was inferior in durability, for example, peeling generate | occur | produced in the adhesion interface under wet heat conditions. In addition, stress relaxation is not necessarily sufficient, and light leakage may occur when it is applied to optical members, such as a polarizing plate. Furthermore, since the adhesive force tends to rise over time after affixing, reworkability was also inadequate.

The present invention has been made in view of such a situation, and when applied to an optical member such as a polarizing plate, it has excellent stress relaxation properties, prevents light leakage, and also has excellent durability and further excellent reworkability. An object is to provide a sheet.

In order to achieve the above object, firstly, the present invention provides a first (meth) acrylic acid ester polymer (A) having a weight average molecular weight of 500,000 to 3 million, and a second (meth) acrylic acid ester having a weight average molecular weight of 8,000 to 300,000. As an adhesive composition containing a polymer (B) and a crosslinking agent (C), the said 1st (meth) acrylic acid ester polymer (A) and the said 2nd (meth) acrylic acid ester polymer (B) are respectively an acidic group substantially. And a hydroxyl group-containing monomer which contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer and which the first (meth) acrylic acid ester polymer (A) contains, and the second (meth) acrylic acid ester polymer ( It is the same kind as the hydroxyl group containing monomer which B) contains, and the said 2nd (meth) acrylic acid ester polymer (B) with respect to the hydroxyl group contained in said 1st (meth) acrylic acid ester polymer (A) The molar ratio of the hydroxyl group is contained, and provides the adhesive composition, characterized in that 1.0 to 40 (invention 1).

The pressure-sensitive adhesive obtained by crosslinking the pressure-sensitive adhesive composition according to the invention (Invention 1) exhibits appropriate cohesion and excellent stress relaxation properties. By using this pressure-sensitive adhesive having excellent stress relaxation properties, when applied to an optical member such as a polarizing plate, an adhesive sheet excellent in both light leakage and durability and furthermore having good reworkability is obtained. Moreover, since each polymer of the said adhesive composition does not contain an acidic group substantially, when a to-be-adhered body consists of a metal or contains a metal, it can suppress that a said metal corrodes.

In the said invention (invention 1), it is preferable that the said 2nd (meth) acrylic acid ester polymer (B) contains 10-40 mass% of said hydroxyl-containing monomers as a monomer unit which comprises the said polymer (invention 2). ).

In the said invention (invention 1, 2), the ratio of the said 2nd (meth) acrylic acid ester polymer (B) with respect to 100 mass parts of said 1st (meth) acrylic acid ester polymers (A) is 5-50 mass parts. Preferred (Invention 3).

In the said invention (Invention 1-3), the said 1st (meth) acrylic acid ester polymer (A) and the said 2nd (meth) acrylic acid ester polymer (B) have reactivity with the said crosslinking agent (C) other than a hydroxyl group. It is preferable that it does not contain a functional group substantially (Invention 4).

In the said invention (Invention 1-4), it is preferable that the said crosslinking agent (C) is an isocyanate type crosslinking agent (invention 5).

In the said invention (invention 5), content of the said isocyanate type crosslinking agent is 0.1-3.5 equivalent with respect to the quantity of the said hydroxyl group in which the isocyanate group of the said isocyanate type crosslinking agent is contained in the said 2nd (meth) acrylic acid ester polymer (B). It is preferable that it is the quantity (invention 6).

Secondly, the present invention provides an adhesive obtained by crosslinking the adhesive compositions (Inventions 1 to 6) (Invention 7).

Thirdly, the present invention provides a pressure-sensitive adhesive sheet comprising a base material and an pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive (invention 7) (invention 8).

In the said invention (invention 8), it is preferable that the said base material is an optical member (invention 9).

Fourthly, the present invention provides a pressure-sensitive adhesive sheet having two release sheets and a pressure-sensitive adhesive layer sandwiched on the release sheet so as to be in contact with the release surfaces of the two release sheets, wherein the pressure-sensitive adhesive layer is the pressure-sensitive adhesive (invention 7). It provides an adhesive sheet, characterized in that (invention 10).

In the adhesive which crosslinked the adhesive composition which concerns on this invention, the three-dimensional network structure by the chemical crosslinking structure of the said low molecular weight polymer is formed by preferentially crosslinking the low molecular weight polymer used conventionally as a plasticizer, It is estimated that a plurality of high molecular weight polymers are inserted into the three-dimensional network structure to constrain the high molecular weight polymers and form a pseudo crosslinked structure between the high molecular weight polymers. As a result, the pressure-sensitive adhesive obtained exhibits excellent stress relaxation property at an appropriate cohesion force, and when applied to an optical member such as a polarizing plate, can effectively prevent light leakage, and is also excellent in durability, and also has good reworkability. Moreover, since each polymer of the adhesive composition which concerns on this invention does not contain an acidic group substantially, when a to-be-adhered body consists of a metal or contains a metal, it can suppress that the said metal corrodes.

1 is a cross-sectional view of an adhesive sheet according to a first embodiment of the present invention.
2 is a cross-sectional view of an adhesive sheet according to a second embodiment of the present invention.
The figure which shows the evaluation criteria of the light leakage test (visual) in the polarizing plate with an adhesive layer (color).

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[Adhesive Composition]

The adhesive composition which concerns on this embodiment has a weight average molecular weight (Mw) of 500,000-3 million 1st (meth) acrylic acid ester polymer (A), and a weight average molecular weight (Mw) of 8000-300,000 2nd (meth) An acrylic ester polymer (B) and a crosslinking agent (C) are contained, Preferably a silane coupling agent (D) is further contained. In addition, in this specification, a (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. Other similar terms are also the same. In addition, a "polymer" shall also include the concept of a "copolymer."

The 1st (meth) acrylic acid ester polymer (A) and the 2nd (meth) acrylic acid ester polymer (B) do not contain an acidic group substantially, respectively, and are hydroxyl group containing monomers (in a molecule | numerator) as a monomer unit which comprises the said polymer. Monomer having a hydroxyl group), and preferably a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group, a hydroxyl group-containing monomer, and a functional group having reactivity with a crosslinking agent (C) used as desired. It is a copolymer with another monomer which does not.

As an acidic group, a carboxyl group is mainly mentioned, and others, a sulfonic acid group, a phosphoric acid group, etc. are mentioned. When the first (meth) acrylic acid ester polymer (A) and the second (meth) acrylic acid ester polymer (B) do not substantially contain an acidic group, the adherend is made of a metal (for example, the adherend is indium tin oxide ( In the case of an electrode made of ITO) or in the case of containing a metal (for example, the adherend contains a metal mesh), corrosion of the metal can be suppressed.

Here, "it does not contain an acidic group substantially" allows containing a trace amount of the grade which prevents a metal from corroding other than not containing an acidic group completely. Specifically, content of the acidic group containing monomer as a structural unit of a polymer (A) or (B) is less than 1 mass% normally, Preferably it is less than 0.5 mass%, Especially preferably, it is less than 0.1 mass%.

As a C1-C20 (meth) acrylic-acid alkylester of an alkyl group, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid n-pentyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, n-dodec (meth) acrylate Thread, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

As a hydroxyl-containing monomer, For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (Meth) acrylic-acid hydroxyalkyl esters, such as 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

In the adhesive composition which concerns on this embodiment, the hydroxyl group containing monomer which a 1st (meth) acrylic acid ester polymer (A) contains, and the hydroxyl group containing monomer which a 2nd (meth) acrylic acid ester polymer (B) contains are the same species, At the same time, the molar ratio of the hydroxyl group contained in the second (meth) acrylic acid ester polymer (B) to the hydroxyl group contained in the first (meth) acrylic acid ester polymer (A) is 1.0 to 40, preferably 3 to 30. Especially preferably, it is 5-20.

In addition, the said molar ratio shows the ratio of the number-of-moles of the hydroxyl group derived from a polymer (B) with respect to the number-of-moles of the hydroxyl group derived from a polymer (A) in an adhesive composition. For example, when 100 mass parts of polymers (A) and 20 mass parts of polymers (B) are mix | blended in an adhesive composition, the ratio of the number-of-moles of the hydroxyl group in the said compounding quantity is shown. In addition, the "same kind" in this specification shall include not only the same hydroxyl group containing monomers but the hydroxyl group containing monomers in which reactivity with a crosslinking agent (C) becomes substantially the same when it exists in the same polymer.

As mentioned above, the said adhesive composition by making the 2nd (meth) acrylic acid ester polymer (B) contain the same amount or more than the 1st (meth) acrylic acid ester polymer (A) in the hydroxyl group derived from the same type of hydroxyl group containing monomer. When crosslinking, it is assumed that the second (meth) acrylic acid ester polymer (B) (low molecular weight polymer) preferentially reacts with the crosslinking agent (C) and forms a three-dimensional network structure through the crosslinking agent (C). In addition, two or more molecules of the first (meth) acrylic acid ester polymer (A) (high molecular weight polymer) are inserted into the three-dimensional network structure without a direct chemical bond or with a very few chemical bonds to form a polymer. It is estimated that (A) forms the pseudo crosslinked structure constrained in the state which has a certain degree of freedom (The structure estimated in this case may be called "structure X" hereafter.). It is thought that a 1st (meth) acrylic acid ester polymer (A) is inserted in the said three-dimensional network structure favorably by containing a comparatively small amount of hydroxyl groups. The pressure-sensitive adhesive having such a structure X exhibits appropriate cohesion and excellent stress relaxation property. Thus, when applied to optical members, such as a polarizing plate, the adhesive which has the outstanding stress relaxation property is excellent in light leakage resistance, excellent also in durability, and can prevent lifting, peeling, etc. even under wet heat conditions. On the other hand, even when the second (meth) acrylic acid ester polymer (B) and the first (meth) acrylic acid ester polymer (A) contain the same amount of hydroxyl group, a polymer having a lower molecular weight than the high molecular weight polymer (A) (B The polymer (B) preferentially reacts with the crosslinking agent (C) because the density of the hydroxyl group is high and the contact with the crosslinking agent (C) due to conformation is small. In addition, in the above structure X, there is no uncrosslinked low molecular weight component or the like for imparting stress relaxation property. Therefore, the bleed out of the low molecular weight component which became a problem with the adhesive of the conventional stress relaxation type | mold does not generate | occur | produce. As a result, the adhesive obtained from the adhesive composition which concerns on this embodiment is excellent also in rework property.

It is preferable that a 2nd (meth) acrylic acid ester polymer (B) contains 10-40 mass% of hydroxyl-containing monomers as a monomer unit which comprises the said polymer, It is preferable to contain 10-30 mass% especially, Furthermore, It is preferable to contain 12-20 mass%. By containing a hydroxyl-containing monomer in the said range, the grade of the crosslinking of a 2nd (meth) acrylic acid ester polymer (B) becomes preferable, and the stress relaxation property of the adhesive obtained by combining with a 1st (meth) acrylic acid ester polymer (A) Can be improved more effectively. When content of a hydroxyl-containing monomer is less than 10 mass%, crosslinking of a 2nd (meth) acrylic acid ester polymer (B) may not be enough and a gel fraction may become low and durability may fall by this. On the other hand, when content of a hydroxyl-containing monomer exceeds 40 mass%, crosslinking of a 2nd (meth) acrylic acid ester polymer (B) will become excessive, there exists a possibility that a stress relaxation property may fall, and a hydroxyl group remains after crosslinking, In particular, the durability under moist heat conditions is poor. Moreover, light leakage resistance of the adhesive sheet obtained becomes more excellent by setting the upper limit of content of a hydroxyl-containing monomer to 30 mass%.

On the other hand, preferable content of the hydroxyl-containing monomer in a 1st (meth) acrylic acid ester polymer (A) is naturally from content of the hydroxyl-containing monomer in the said 2nd (meth) acrylic acid ester polymer (B), and the molar ratio of the hydroxyl group mentioned above. It is decided.

As said other monomer, the (meth) acrylic acid ester, acrylamide, and methacrylamide which have aromatic rings, such as (meth) acrylic acid ester and aliphatic rings, such as cyclohexyl (meth) acrylic acid and phenyl (meth) acrylate, for example (Meth) acrylic acid ester, vinyl acetate, which has non-crosslinkable tertiary amino groups, such as non-crosslinkable acrylamide, (meth) acrylic acid N, N-dimethyl amino ethyl, (meth) acrylic acid N, N-dimethyl aminopropyl, etc. Styrene and the like. These may be used independently and may be used in combination of 2 or more type.

Among the said other monomers, (meth) acrylic acid ester which has non-crosslinkable tertiary amino groups, such as (meth) acrylic acid N, N-dimethyl amino ethyl, (meth) acrylic acid N, and N-dimethyl aminopropyl, especially (meth) acrylic acid N N-dimethyl amino ethyl is included as a monomer unit constituting the polymer in the second (meth) acrylic acid ester polymer (B) because it has a catalytic effect of promoting the reaction between the hydroxyl group and the crosslinking agent (C) in the polymer. You may be.

In this case, it is preferable that content of the (meth) acrylic acid ester which has the said non-crosslinkable tertiary amino group in a 2nd (meth) acrylic acid ester polymer (B) is 0.1-10 mass%, Especially 1-5 mass% Is preferably.

Here, also in order to form said structure X reliably, the 1st (meth) acrylic acid ester polymer (A) and the 2nd (meth) acrylic acid ester polymer (B) are functional groups which are reactive with a crosslinking agent (C) other than a hydroxyl group. It is preferable not to contain substantially. As such a functional group, a crosslinkable primary amino group or a secondary amino group is mentioned, for example, As a monomer containing the said functional group, For example, amino ethyl (meth) acrylate and n-butyl amino ethyl (meth) acrylate Etc. can be mentioned.

The term "substantially does not contain a functional group reactive with the crosslinking agent (C)" allows the inclusion of the functional group to the extent that it does not interfere with the reactivity of the hydroxyl group and the crosslinking agent (C), in addition to not completely containing the functional group. . Specifically, in each polymer (A) and (B), it is preferable that molar ratio with respect to the hydroxyl group of the said functional group is 0.2 or less, and it is especially preferable that it is 0.1 or less.

A random copolymer may be sufficient as the superposition | polymerization form of a 1st (meth) acrylic acid ester polymer (A) and a 2nd (meth) acrylic acid ester polymer (B), respectively, and a block copolymer may be sufficient as it.

The weight average molecular weight of a 1st (meth) acrylic acid ester polymer (A) is 500,000-3 million, Preferably it is 700,000-2,500,000, Especially preferably, it is 1 million-2 million. In other words, the first (meth) acrylic acid ester polymer (A) consists of a high molecular weight polymer component. In addition, the weight average molecular weight in this specification is a polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

It is estimated that the said structure X is formed satisfactorily because the weight average molecular weight of a 1st (meth) acrylic acid ester polymer (A) exists in the said range, and a polymer (A) has a comparatively large molecular weight.

If the weight average molecular weight of a 1st (meth) acrylic acid ester polymer (A) is less than 500,000, the adhesive gel fraction obtained will be low and there exists a possibility that durability and rework property may be inferior. Moreover, when the weight average molecular weight of a 1st (meth) acrylic acid ester polymer (A) exceeds 3 million, compatibility with a 2nd (meth) acrylic acid ester polymer (B) etc. will deteriorate, and the stress relaxation property of the adhesive obtained will fall. There is a concern.

On the other hand, the weight average molecular weight of a 2nd (meth) acrylic acid ester polymer (B) is 8000-300,000, Preferably it is 10,000-200,000, Especially preferably, it is 50,000-100,000. In other words, the second (meth) acrylic acid ester polymer (B) is composed of a low molecular weight polymer component.

When the weight average molecular weight of a 2nd (meth) acrylic acid ester polymer (B) exists in the said range, the three-dimensional network structure peculiar to the adhesive composition which concerns on this embodiment is formed, and contributes to the outstanding stress relaxation property. In other words, when the weight average molecular weight of the second (meth) acrylic acid ester polymer (B) is less than 8000, a good three-dimensional network structure cannot be obtained. On the other hand, when the weight average molecular weight of a 2nd (meth) acrylic acid ester polymer (B) exceeds 300,000, compatibility with a 1st (meth) acrylic acid ester polymer (A) etc. will fall and it will be formed by the polymer (B). Insertion of the polymer (A) into the three-dimensional network structure becomes insufficient, and as a result, the obtained adhesive may be inferior in durability and reworkability.

In this embodiment, said 1st (meth) acrylic acid ester polymer (A) and 2nd (meth) acrylic acid ester-type polymer (B) may respectively be used individually by 1 type, and may be used in combination of 2 or more type Also good.

It is preferable that the ratio of the 2nd (meth) acrylic acid ester polymer (B) with respect to 100 mass parts of 1st (meth) acrylic acid ester polymers (A) is 5-50 mass parts, It is especially preferable that it is 5-40 mass parts, Furthermore, it is preferable that it is 10-30 mass parts.

The adhesive obtained from the adhesive composition containing a 1st (meth) acrylic acid ester polymer (A) and a 2nd (meth) acrylic acid ester polymer (B) in the said ratio is estimated to form the said structure X favorably.

As a crosslinking agent (C), an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aziridine type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned, Especially, the isocyanate type crosslinking agent which is excellent in the reactivity with the hydroxyl group which polymer (A) and (B) has desirable.

Isocyanate-based crosslinking agents include at least a polyisocyanate compound. As a polyisocyanate compound, For example, aromatic polyisocyanate, such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate, aliphatic polyisocyanate, such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, for example. Alicyclic polyisocyanates such as isocyanates, and their reactants with low molecular weight active hydrogen-containing compounds such as biuret bodies, isocyanurates, and ethylene glycol, propylene glycol, neopentyl glycol, trimetholpropane and castor oil. Adduct body etc. are mentioned.

The said crosslinking agent (C) can be used individually by 1 type or in combination of 2 or more type.

As for content of a crosslinking agent (C), the crosslinkable group (for example, isocyanate group) of the said crosslinking agent (C) becomes 0.05-5 equivalent normally with respect to the quantity of the hydroxyl group of a 2nd (meth) acrylic acid ester polymer (B). Amount, preferably 0.1 to 3.5 equivalents, particularly preferably 0.3 to 1.0 equivalents. When the quantity of the said crosslinkable group is less than 0.05 equivalent, the adhesive gel fraction obtained is low and there exists a possibility that sufficient cohesion force may not be exhibited. Moreover, if the quantity of the said crosslinkable group is 0.1 equivalent or more, especially 0.3 equivalent or more, the adhesive obtained can be made more excellent in durability. On the other hand, if the quantity of the said crosslinkable group is 3.5 equivalent or less, the adhesive force of the adhesive obtained can be fully ensured. Furthermore, if the amount of the crosslinkable group is 1.0 equivalent or less, it is estimated that the crosslinking agent (C) can be contributed only to the formation of the three-dimensional network structure of the polymer (B), so that crosslinking of the polymer (A) can be effectively prevented. As a result, the obtained adhesive becomes excellent in stress relaxation property.

The adhesive composition which concerns on this embodiment, Preferably contains a silane coupling agent (D) further. When the silane coupling agent (D) is contained, the alkoxysilyl group and the like of the silane coupling agent (D) act on the adherend surface such as a glass substrate. Thus, when the polarizing plate is bonded to a liquid crystal glass cell or the like, for example, The adhesiveness between the liquid crystal glass cell is better.

As the silane coupling agent (D), an organosilicon compound having at least one alkoxysilyl group in a molecule is suitable for having good compatibility with the pressure-sensitive adhesive component and having a light transmittance, for example, a substantially transparent one. It is preferable that it is 0.01-0.5 mass part with respect to 100 mass parts of 1st (meth) acrylic acid ester polymers (A), and, as for the addition amount of such a silane coupling agent (D), it is especially preferable that it is 0.05-0.3 mass parts.

Specific examples of the silane coupling agent (D) include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane Silicon compounds having an epoxy structure such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy And amino group-containing silicon compounds such as silane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. These may be used individually by 1 type and may be used in combination of 2 or more type.

To the pressure-sensitive adhesive composition, various additives commonly used in acrylic pressure-sensitive adhesives, for example, antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index adjusters and the like can be added.

[Manufacturing Method of Adhesive Composition]

The pressure-sensitive adhesive composition is prepared for each of the first (meth) acrylic acid ester polymer (A) and the second (meth) acrylic acid ester polymer (B), and mixed with them, and at the same time, the crosslinking agent (C) and It can manufacture by adding a silane coupling agent (D) as needed.

As a preferable specific example, (meth) acrylic acid ester polymer (A) and (B) are manufactured separately by a normal radical polymerization method, respectively. The polymerization of the (meth) acrylic acid ester polymers (A) and (B) can be carried out by a solution polymerization method or the like, using a polymerization initiator if 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. As an azo type compound, 2, 2'- azobisisobutyronitrile, 2, 2'- azobis (2-methylbutyronitrile), 1, 1'- azobis (cyclohexane 1-carbo, for example) Nitrile, 2, 2'-azobis (2, 4-dimethylvaleronitrile), 2, 2'-azobis (2, 4-dimethyl-4-methoxyvaleronitrile), dimethyl 2, 2'-azo Bis (2-methylpropionate), 4, 4'-azobis (4-cyanobareric acid), 2, 2'-azobis (2-hydroxymethylpropionitrile), 2, 2'-azo Bis [2- (2-imidazolin-2-yl) propane] and the like.

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

In addition, 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.

Next, the solution of the obtained polymers (A) and (B) is mixed and a dilution solvent is added. Thereafter, a crosslinking agent (C) and a silane coupling agent (D) are added as desired and mixed sufficiently to obtain a pressure-sensitive adhesive composition (coating solution) diluted with a solvent.

As a diluting solvent for diluting an adhesive composition to make a coating solution, For example, aliphatic hydrocarbons, such as hexane, heptane, cyclohexane, aromatic hydrocarbons, such as toluene and xylene, halogenated hydrocarbons, such as methylene chloride and ethylene chloride, methanol, ethanol Alcohols such as propanol, butanol and 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and ethylcell Cellosolve solvents, such as a solvent, etc. can be used.

As a density | concentration and a viscosity of the coating solution manufactured in this way, what is necessary is just a range which can be coated, and it does not restrict | limit especially, It can select suitably according to a situation. For example, it dilutes so that the density | concentration of an adhesive composition may be 10-40 mass%. On the other hand, when obtaining a coating solution, addition of a dilution solvent etc. is not a requirement, and if it is a viscosity etc. which an adhesive composition can coat, it is not necessary to add a dilution solvent. In this case, an adhesive composition turns into a coating solution as it is.

〔adhesive〕

The adhesive which concerns on this embodiment crosslinks the said adhesive composition. Crosslinking of the said adhesive composition can be performed by heat processing. In addition, the said heat processing can also serve as the drying process at the time of volatilizing the dilution solvent etc. of an adhesive composition.

When performing heat processing, it is preferable that heating temperature is 50-150 degreeC, and it is especially preferable that it is 70-120 degreeC degree. Moreover, it is preferable that heating time is 30 second-3 minutes, and it is preferable that it is 50 second-2 minutes especially. Moreover, it is especially preferable to set a 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 second (meth) acrylic acid ester polymer (B) is crosslinked by the crosslinking agent (C), and the first (meth) acrylic acid ester polymer (A) is added to the three-dimensional network structure. Inserted, it is assumed that the structure X is formed.

It is preferable that the adhesive force with respect to the alkali free glass is 0.1-25 N / 25 mm, and it is especially preferable that it is 2-20 N / 25 mm. On the other hand, the adhesive force here means 180 degree pull-out adhesive force (peel rate 300mm / min) based on JISZ0237, and pressurizes at 0.5 MPa and 50 degreeC for 20 minutes, and affixes to a to-be-adhered body, 23 degreeC and 50% It shall be measured after leaving for 24 hours under conditions of RH. Since adhesive force exists in the said range, when it applies to optical members, such as a polarizing plate, lifting, peeling, etc. can be prevented.

It is preferable that the adhesive force (adhesive force after 14 days of sticking) after leaving the adhesive to this to-be-adhered body for 14 days from 23 ° C and 50% RH conditions from the sticking to the said to-be-adhered body is 0.1-25 N / 25mm, It is especially preferable that it is 2-20N / 25mm. Thus, since the increase of the adhesive force with time progress is suppressed, the adhesive which concerns on this embodiment can be evaluated as being excellent in rework property.

The adhesive described above can be used suitably for an optical member, For example, adhesion of optical members, such as a polarizing plate (polarizing film) and retardation plate (phase difference film), or a polarizing plate (polarizing film) and retardation plate (phase difference), for example Film) and glass substrates. Since the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive according to the present embodiment has an excellent stress relaxation property, even when the size change of the adherend is large, the pressure that can be generated by the size change is absorbed and relaxed by the pressure-sensitive adhesive layer. Therefore, the light leakage can be effectively prevented when used for the optical member as described above without peeling off the adherend over a long period of time. In other words, the pressure-sensitive adhesive according to the present embodiment achieves both light leakage resistance and durability. Moreover, since the adhesive which concerns on this embodiment has favorable rework property and is free from an acid, when the to-be-adhered body consists of a metal or contains a metal, it is excellent in corrosion resistance.

[Adhesion sheet]

As shown in FIG. 1, the adhesive sheet 1A which concerns on 1st Embodiment has the adhesive sheet 11 laminated | stacked on the peeling sheet 12 and the peeling surface of the peeling sheet 12 in order from the bottom. And the base material 13 laminated on the pressure-sensitive adhesive layer 11.

In addition, as shown in FIG. 2, the adhesive sheet 1B which concerns on 2nd Embodiment is made to contact the peeling surface of two peeling sheets 12a and 12b and those two peeling sheets 12a and 12b. It consists of the adhesive layer 11 sandwiched between the said 2 sheets of peeling sheets 12a and 12b. In addition, the peeling surface of a peeling sheet in this specification means the surface which has peelability in a peeling sheet, and includes both the surface which performed peeling process and the surface which shows peelability, even without peeling process.

In any adhesive sheet 1A, 1B, the adhesive layer 11 becomes an adhesive formed by bridge | crosslinking the adhesive composition mentioned above.

Although the thickness of the adhesive layer 11 is suitably determined according to the purpose of use of the adhesive sheets 1A and 1B, it is usually 5-100 micrometers, Preferably it is the range of 10-60 micrometers, For example, for optical members, especially a polarizing plate When using as an adhesive layer, it is 10-50 micrometers, It is preferable that it is 10-30 micrometers especially.

There is no restriction | limiting in particular as the base material 13, Any thing used as a base material sheet of a normal adhesive sheet can be used. For example, woven or nonwoven fabrics using fibers of other desired optical members, such as rayon, acrylic, polyester, etc .; Paper such as quality paper, glassine paper, impregnated paper and coated paper; Metal foils such as alumina and copper; Foams such as urethane foams and polyethylene foams; Polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, polyvinyl chloride films, polyvinylidene chloride films, poly Plastic films such as vinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norbornene-based resin films, and cycloolefin resin films; These 2 or more types of laminated bodies etc. are mentioned. The plastic film may be uniaxially extended or biaxially extended.

As an optical member, a polarizing plate (polarizing film), a polarizer, a retardation plate (retardation film), a viewing angle compensation film, a brightness improvement film, a contrast improvement film, a liquid crystal polymer film, etc. are mentioned, for example. Among these, since a polarizing plate (polarizing film) is easy to shrink | contract and has a big dimension change, it is suitable as an object of forming the adhesive (the said adhesive layer 11) of this embodiment from a light-proof leak-proof viewpoint.

Although the thickness of the base material 13 changes also with the kind, For example, in the case of an optical member, it is 10 micrometers-500 micrometers normally, Preferably they are 50 micrometers-300 micrometers.

As the release sheets 12, 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 , Polycarbonate film, polyimide film, fluororesin film and the like can be used. Moreover, such a crosslinked film can also be used. Furthermore, such a laminated film may be sufficient.

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

Although there is no restriction | limiting in particular about the thickness of release sheet 12, 12a, 12b, Usually, it is about 20-150 micrometers.

In order to manufacture the said adhesive sheet 1A, after apply | coating the solution (coating solution) containing the said adhesive composition to the peeling surface of the peeling sheet 12, and heat-processing to form the adhesive layer 11, The base material 13 is laminated | stacked on the adhesive layer 11. After that, it is preferable to set the curing period.

In addition, the conditions of heat processing and curing are as above-mentioned.

Moreover, in manufacturing the said adhesive sheet 1B, the coating solution containing the said adhesive composition is apply | coated to the peeling surface of one peeling sheet 12a (or 12b), and it heat-processes the adhesive layer 11 ), The peeling surface of the other peeling sheet 12b (or 12a) is superimposed on the adhesive layer 11.

As a method of apply | coating the said coating solution, the bar coat method, the knife coat method, the roll coat method, the braid coat method, the die coat method, the gravure coat method, etc. can be used, for example.

Here, for example, in manufacturing the liquid crystal display device which consists of a liquid crystal cell and a polarizing plate, the polarizing plate is used as the base material 13 of the adhesive sheet 1A, and the peeling sheet 12 of the said adhesive sheet 1A is carried out. It is good to peel off and bond the exposed adhesive layer 11 and liquid crystal cell together.

In addition, for example, to manufacture a liquid crystal display device in which a retardation plate is disposed between a liquid crystal cell and a polarizing plate, as an example, first, one peeling sheet 12a (or 12b) of the adhesive sheet 1B is peeled off. The exposed adhesive layer 11 and the retardation plate of the adhesive sheet 1B are bonded together. Next, the peeling sheet 12 of the adhesive sheet 1A using the polarizing plate as the base material 13 is peeled off, and the exposed adhesive layer 11 and the retardation plate of the adhesive sheet 1A are bonded together. Furthermore, the other peeling sheet 12b (or 12a) is peeled from the adhesive layer 11 of the said adhesive sheet B, and the exposed adhesive layer 11 and liquid crystal cell of the adhesive sheet B are bonded together. .

According to the above-mentioned adhesive sheets 1A and 1B, since the adhesive layer 11 is very excellent in stress relaxation property, even if it is applied to adhesion of a polarizing plate, even if it is applied to adhesion of a polarizing plate, for example, the pressure-sensitive adhesive layer may generate | occur | produce the stress which may be generated by deformation of a polarizing plate. It can be absorbed and alleviated by (11), and it is estimated that the outstanding light leakage resistance and high durability are exhibited by this.

The embodiments described above are described for ease of understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the said embodiment is the meaning including all the design changes and equivalents which belong to the technical scope of this invention.

For example, the peeling sheet 12 of the adhesive sheet 1A may be omitted, and either one of the peeling sheets 12a and 12b in the adhesive sheet 1B may be omitted.

[Examples]

Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples.

EXAMPLE 1

1. Preparation of Polymer (A)

99.0 parts by mass of n-butyl acrylate, 1.0 part by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 2, 2 ”-azo in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube. 0.08 mass part of bisisobutyronitrile was put, and the air in the said reaction container was substituted by nitrogen gas. While stirring in this nitrogen atmosphere, the reaction solution was heated to 60 ° C. and allowed to react for 16 hours, and then cooled to room temperature. Here, the molecular weight was measured by the method of mentioning a part of obtained solution later, and generation | occurrence | production of the polymer (A) of the weight average molecular weight 1.57 million was confirmed.

2. Preparation of Polymer (B)

85.0 parts by mass of n-butyl acrylate, 15.0 parts by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 2, 2 ”-azo into a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. 0.08 mass part of bisisobutyronitrile was put, and the air in the said reaction container was substituted by nitrogen gas. While stirring under this nitrogen atmosphere, the reaction solution was heated to 60 ° C, reacted for 16 hours, and then cooled to room temperature. Here, molecular weight was measured by the method of mentioning a part of obtained solution later, and production | generation of the polymer (B) of 60,000 weight average molecular weight was confirmed.

3. Preparation of Adhesive Composition

After mixing 100 mass parts (solid content conversion value) of the polymer (A) obtained at the said process (1), and 20 mass parts (solid content conversion value) of the polymer (B) obtained at the said process (2), as a crosslinking agent (C) And 3.0 parts by mass of xylene diisocyanate addition product manufactured by Mitsui Chemical Co., Ltd., trade name "Takenate D-110N" of trimethyrol propane in an amount corresponding to 0.6 equivalent of hydroxyl group of the polymer (B). Finally, 0.3 mass part of 3-glycidoxy propyl trimethoxysilane (made by Shin-Etsu Chemical Co., Ltd., brand name "KBM403") was added as a silane coupling agent (D), and the diluting solution of the adhesive composition was obtained by fully stirring.

On the other hand, from the ratio of the blended monomers, the amount of hydroxyl groups (H [OH]) in 100 g of the polymer (A) is 8.62 mmol, and the amount (L [OH]) of hydroxyl groups in 20 g of the polymer (B) is calculated as 25.84 mmol. do. Therefore, the ratio (L [OH] / H [OH]) of the number of moles of hydroxyl groups in 20 parts by mass of the polymer (B) to the number of moles of hydroxyl groups in 100 parts by mass of the polymer (A) is 3.00.

Here, the mixing | blending of the said adhesive composition is shown in Table 1. In addition, the details, such as the symbol of Table 1, are as follows.

[Polymers (A) and (B)]

BA: n-butyl acrylate

AA: Acrylic acid

DM: Methacrylic acid N, N-dimethylaminoethyl

HEA: 2-hydroxyethyl acrylate

H [OH] (mmol): mole number of hydroxyl group which calculated polymer (A) addition amount (mass part) as (g)

L [OH] (mmol): mole number of hydroxyl group which calculated polymer (B) addition amount (mass part) as (g)

[Isocyanate Crosslinking Agent (C)]

XDI-TMP: Xylene diisocyanate adduct of trimetholpropane (manufactured by Mitsui Chemical Co., Ltd., trade name "Takenate D-110N")

TDI-TMP: Tolylene diisocyanate adduct of trimetholpropane (manufactured by Nippon Polyurethanes, trade name "Colonate L")

[Silane Coupling Agent (D)]

KBM403: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403")

Knife coater so that the thickness after drying may be 25 micrometers on the peeling process surface of the peeling sheet (The Lintec company make SP-PET3811, thickness: 38 micrometers) which peeled the single side | surface of a polyethylene terephthalate film with the silicone type peeling agent in the dilute solution of the obtained adhesive composition. After apply | coating with the heat processing, it heat-processed at 90 degreeC for 1 minute, and formed the adhesive layer.

Next, the polarizing plate which consists of a polarizing film with a disk liquid crystal layer and the viewing angle expansion film integrated is bonded together so that the exposed surface of an adhesive layer and the surface of a disk liquid crystal layer may contact, and it is 23 degreeC, 50% RH By curing for 7 days, the polarizing plate with an adhesive layer was obtained.

[Examples 2 to 10 and Comparative Examples 1 to 7]

The type and proportion of each monomer constituting the adhesive composition, the type and amount of the crosslinking agent and the silane coupling agent, and the compounding ratio of the polymer (A) and the polymer (B) are changed as shown in Table 1, except that To prepare a polarizing plate with an adhesive layer.

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

<Measurement 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 G2000 HXL

Measurement solvent: tetrahydrofuran

Measurement temperature: 40 ℃

[Test Example 1] (Light Leak Test)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was adjusted to 233 mm x 309 mm size using the cutting device (Super cutter made by Ogino Seisakusho Co., PN1-600). The peeling sheet was peeled off and affixed on the alkali free glass (Eagle XG, Corning Co., Ltd.) through the exposed adhesive layer, and it pressurized for 20 minutes at 0.5 Mpa and 50 degreeC by the autoclave by Kurihara Seisakusho company. On the other hand, the said bonding was performed in the front and back of an alkali free glass so that a polarizing axis with an adhesive layer might be in a cross nicol state (polarization axis: 45 degrees, 135 degrees). In this state, after leaving for 250 hours in an environment of 80 ° C. dry, it was left for 2 hours in an environment of 23 ° C. and 50% RH, and as a sample, light leakage was evaluated by the method shown below. The results are shown in Table 2.

 <Light leakage evaluation: naked eye>

The sample was installed on a flat illuminator (manufactured by Dentsu Industries Co., Ltd., HF-SL-A312LC, roughness: 26,000 Lux, luminance: 10,000 cd), and photographed with a two-dimensional colorimeter (Konica Minolta, CA-2000). The analysis software (CA-S20w, manufactured by Konica Minolta Co., Ltd.) converted the luminance distribution image. The luminance distribution image of the obtained sample was evaluated based on the evaluation criteria shown in FIG.

[Test Example 2] (Durability Evaluation)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was adjusted to 233 mm x 309 mm size using the cutting device (Super cutter made by Ogino Seisakusho Co., PN1-600). The peeling sheet was peeled off and affixed on the alkali free glass (Eagle XG, Corning Co., Ltd.) through the exposed adhesive layer, and it pressurized for 20 minutes at 0.5 Mpa and 50 degreeC by the autoclave by Kurihara Seisakusho Co., Ltd.

Then, it put in the environment of the following durable conditions, and after 500 hours, observation was performed using the 10 times magnifier. The appearance change was based on the following. The results are shown in Table 2.

◎: There is not a fault in four sides

(Circle): No flaw in the part more than 0.6mm from the outer peripheral end in 4 sides

X: At least 1 side of 4 sides has an external defect of 0.1 mm or more of adhesives, such as lifting, peeling, foaming, and a stripe, in a part 0.6 mm or more from an outer peripheral end part.

<Durability>

60 ° C, 90% RH

[Test Example 3] (Reworkability Evaluation)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was cut out, and the sample of 25 mm width and 100 mm length was produced. After peeling a peeling sheet from this sample and affixing the said sample to alkali-free glass (Eagle XG, Corning Co., Ltd.) through the exposed adhesive layer, it carried out for 20 minutes by 0.5 MPa and 50 degreeC in the autoclave by Kurihara Seisakusho Co., Ltd. Pressurized. Then, it was left to stand for 48 hours under the conditions of 50 degreeC dry, and it humidified for 3 hours on 23 degreeC and 50% RH conditions. Then, the sample was peeled off by hand from the alkali free glass, and the dirt of the surface of the said alkali free glass was visually evaluated. Evaluation was performed based on the following. The results are shown in Table 2.

○: There is no residual of the dirt, the adhesive of the glass

(Triangle | delta): There exists some residual of the dirt, adhesive of glass

X: Remaining dirt, adhesive of glass is remarkable

[Test Example 4] (Evaluation of Corrosion Resistance)

The peeling sheet of the polarizing plate with an adhesive layer obtained by the Example or the comparative example was peeled off, and after affixing on copper foil (thickness: 80 micrometers), it stored for 60 hours in 60 degreeC and 90% RH atmosphere. Then, the polarizing plate with an adhesive layer was peeled off from the said copper foil, the surface of the exposed copper foil was visually observed, and the presence or absence of corrosion was confirmed. The results are shown in Table 2.

○: no corrosion

×: Corrosion

[Test Example 5] (Evaluation of haze value)

The structure (structure before polarizing plate sticking) which consists of a peeling sheet / adhesive layer (thickness: 25 micrometers) obtained in the manufacturing process of an Example or a comparative example was prepared. The measurement sample was produced by affixing the exposed adhesive layer surface of this structure and soda-lime glass (haze value 0%), and peeling a peeling sheet.

About the said measurement sample, haze value (%) (it may be abbreviated in Hz (%)) according to JISK7105 using the haze meter (NDH2000 by Nippon Denshoku Co., Ltd.). On the other hand, the range of a preferable haze value is 0 to 3%, the thing in the said range was evaluated as (circle) and the thing outside the said range as x. The results are shown in Table 2.

As can be seen from Table 2, in the polarizing plate with the pressure-sensitive adhesive layer obtained in the Examples, both of light leakage resistance and durability were excellent, and all of rework resistance, corrosion resistance and optical properties were good.

The adhesive composition and adhesive of this invention are suitable for adhesion | attachment of an optical member, for example, a polarizing plate and a retardation plate, and the adhesive sheet of this invention is suitable as an adhesive sheet for optical members, such as a polarizing plate and a retardation plate.

1A, 1B... Adhesive sheet
11 ... The pressure-
12, 12a, 12b... Peeling sheet
13 ... materials

Claims (10)

The weight average molecular weight is 500,000 to 3 million first (meth) acrylic acid ester polymer (A),
The weight average molecular weight is 8000 to 300,000 second (meth) acrylic acid ester polymer (B),
As an adhesive composition containing a crosslinking agent (C),
The said 1st (meth) acrylic acid ester polymer (A) and said 2nd (meth) acrylic acid ester polymer (B) do not contain an acidic group substantially, respectively, and also it contains a hydroxyl group containing monomer as a monomer unit which comprises the said polymer. Contains,
It is the same kind as the hydroxyl group containing monomer which the said 1st (meth) acrylic acid ester polymer (A) contains, and the hydroxyl group containing monomer which the said 2nd (meth) acrylic acid ester polymer (B) contains,
The molar ratio of the hydroxyl group contained in the said 2nd (meth) acrylic acid ester polymer (B) with respect to the hydroxyl group contained in said 1st (meth) acrylic acid ester polymer (A) is 1.0-40, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The said 2nd (meth) acrylic acid ester polymer (B) contains 10-40 mass% of said hydroxyl group containing monomers as a monomer unit which comprises the said polymer, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The ratio of the said 2nd (meth) acrylic acid ester polymer (B) with respect to 100 mass parts of said 1st (meth) acrylic acid ester polymers (A) is 5-50 mass parts, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The said 1st (meth) acrylic acid ester polymer (A) and the said 2nd (meth) acrylic acid ester polymer (B) do not contain functional group which has reactivity with the said crosslinking agent (C) substantially other than a hydroxyl group, It is characterized by the above-mentioned. Adhesive composition. The method according to claim 1,
Said crosslinking agent (C) is an isocyanate type crosslinking agent, The adhesive composition characterized by the above-mentioned. The method according to claim 5,
Content of the said isocyanate type crosslinking agent is an amount whose isocyanate group of the said isocyanate type crosslinking agent becomes 0.1-3.5 equivalent with respect to the quantity of the said hydroxyl group contained in the said 2nd (meth) acrylic acid ester polymer (B). The adhesive which crosslinks the adhesive composition of any one of Claims 1-6. As an adhesive sheet provided with a base material and an adhesive layer,
The pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive according to claim 7 characterized in that the pressure-sensitive adhesive sheet. The method according to claim 8,
Said base material is an optical member, The adhesive sheet characterized by the above-mentioned. With two pieces of peeling sheets,
An adhesive sheet provided with the adhesive layer clamped by the said peeling sheet so that the peeling surface of the said 2 peeling sheets may be contacted,
The pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive according to claim 7 characterized in that the pressure-sensitive adhesive sheet.

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