JP2016199663A - Ultraviolet-curable adhesive composition and adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curable adhesive composition capable of stably obtaining an adhesive which has excellent curability and is excellent in adhesive characteristics, transparency and step difference followability, and to provide an adhesive sheet using the same.SOLUTION: An ultraviolet-curable adhesive composition contains a hydrogenated polybutadiene skeleton urethane acrylate oligomer as (A) component, a non-hydrophilic (meth)acrylate monomer as (B) component, and a hydrogenated terpene resin as (C) component. The (B) component contains isostearyl (meth)acrylate and lauryl (meth)acrylate. An amount of the (B) component to be blended is set to be a value in a range of 95-205 pts.wt. with respect to 100 pts.wt. of the (A) component, and an amount of the (C) component to be blended is set to be a value in a range of 45-95 pts.wt. with respect to 100 pts.wt. of the (A) component.SELECTED DRAWING: Figure 2

Description

The present invention relates to an ultraviolet curable pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.
In particular, the present invention relates to an ultraviolet curable pressure-sensitive adhesive composition capable of stably obtaining a pressure-sensitive adhesive having excellent curability and excellent pressure-sensitive adhesive properties, transparency, and step following ability, and a pressure-sensitive adhesive sheet using the same.

2. Description of the Related Art Conventionally, touch panels that combine an image display device such as a liquid crystal display and a position input device such as a touch pad have been widely used in the fields of smartphones and tablet terminals.
In such a touch panel, a sheet-like pressure-sensitive adhesive made of an optical transparent pressure-sensitive adhesive is used for the purpose of bonding optical members.

In particular, in a capacitive touch panel, a glass plate or the like as a top plate is usually laminated on the viewing side of the conductive pattern layer via a hard coat film.
At this time, conventionally, an air gap is often formed between the hard coat film and the conductive pattern layer.

However, such an air gap causes a difference in refractive index between the hard coat film, the conductive pattern layer, and the like, leading to a decrease in luminance and contrast due to light scattering, and the visibility of the screen is likely to decrease. There was a problem.
Therefore, in recent years, a technique has been adopted in which a thick film layer made of an optical transparent adhesive is provided on the entire surface of the laminated surface of the hard coat film and the conductive pattern layer to fill the air gap.

In addition, when such an optically transparent adhesive is formed from a solvent-type adhesive composition, bubbles resulting from the solvent are generated in the step of drying the solvent, and the transparency of the optically transparent adhesive is likely to be lowered. It has been known.
In particular, when the optical transparent pressure-sensitive adhesive is formed as a thick film layer, the decrease in transparency tends to be remarkable.
Therefore, as the pressure-sensitive adhesive composition for forming the optically transparent pressure-sensitive adhesive, an ultraviolet curable pressure-sensitive adhesive composition that is a solventless pressure-sensitive adhesive composition is preferably used (for example, see Patent Documents 1 and 2). ).

That is, Patent Document 1 discloses that the polyurethane (A) having a (meth) acryloyl group is 20 to 50% by weight, the (meth) acrylic acid ester (B) having a hydroxyl group is 5 to 20% by weight, and a photopolymerization initiator. (D) is contained in an amount of 0.2 to 5% by weight, and the polyurethane (A) reacts with a polyolefin polyol and a polyisocyanate to obtain a polyurethane having a hydroxyl group or an isocyanate group, and then an isocyanate group and a (meth) acryloyl group. Or a compound having a hydroxyl group and a (meth) acryloyl group, the weight average molecular weight is 10,000 to 300,000, and the relative permittivity of the cured product at 1 MHz is 2 to 4. A curable composition for a transparent pressure-sensitive adhesive sheet is disclosed.
It also describes that 30 to 85% by weight of photopolymerizable monomer (C) other than polyurethane (A) and (meth) acrylic acid ester (B) is contained.

  Patent Document 2 discloses that (A) component: a hydrogenated conjugated diene polymer containing a hydrogenated conjugated diene polymer site and a reactive double bond, and (B) component: 8 to 18 carbon atoms. Solventless active energy ray-curable optical pressure-sensitive adhesive composition comprising the following monomer having a linear or branched alkyl group and component (C): a monomer having a hydroxyl group and / or a nitrogen atom-containing group The weight average molecular weight of the component (A) is 10,000 or more and 100,000 or less, the content of the component (A), the content of the component (B), and the content of the component (C) The active energy ray-curable optical pressure-sensitive adhesive composition is disclosed in which the content of the component (C) is 5% by weight or more and 20% by weight or less with respect to the total of

JP 2013-242724 A (Claims) JP 2014-214275 A (Claims)

However, the curable composition for transparent pressure-sensitive adhesive sheets described in Patent Document 1 includes polyurethane (A), (meth) acrylic acid ester (B) having a hydroxyl group, and other photopolymerizable monomers (C). As a result, there was a problem that the pressure-sensitive adhesive properties of the obtained pressure-sensitive adhesive sheet were low in a high-temperature and high-humidity environment.
In addition, the pressure-sensitive adhesive sheet obtained from the curable composition for transparent pressure-sensitive adhesive sheets described in Patent Document 1 is capable of following a step formed by a printed pattern, wiring, or the like on the laminated surface of the optical member (hereinafter, “step following property”). However, there is a problem that bubbles and voids are likely to be generated around the step, which may adversely affect the optical performance of the touch panel.

  Also in the active energy ray-curable optical pressure-sensitive adhesive composition described in Patent Document 2, a hydrogenated conjugated diene polymer as component (A) and a monomer having a predetermined alkyl group as component (B) In addition, since the compatibility with the monomer having a hydroxyl group or the like as the component (C) is insufficient, the pressure-sensitive adhesive sheet obtained has low pressure-sensitive adhesive properties in a high-temperature and high-humidity environment, and the step-following property is also insufficient. There was a problem.

Therefore, as a result of intensive studies, the present inventor blends a predetermined non-hydrophilic (meth) acrylate monomer and a hydrogenated terpene resin in a predetermined blending amount with respect to the hydrogenated polybutadiene skeleton urethane acrylate oligomer. Thus, the inventors have found that the compatibility of the components can be effectively improved to solve the above-described problems, and the present invention has been completed.
That is, an object of the present invention is to provide an ultraviolet curable pressure-sensitive adhesive composition that has excellent curability and can stably obtain a pressure-sensitive adhesive having excellent adhesive properties, transparency, and step following ability, and the same. It is to provide an adhesive sheet.

According to the present invention, a hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A), a non-hydrophilic (meth) acrylate monomer as the component (B), and a hydrogenated terpene resin as the component (C). An ultraviolet curable pressure-sensitive adhesive composition comprising: (B) component containing isostearyl (meth) acrylate and lauryl (meth) acrylate, and blending amount of (B) component to 100 parts by weight of (A) component On the other hand, the value is in the range of 95 to 205 parts by weight, and the blending amount of component (C) is set to a value in the range of 45 to 95 parts by weight with respect to 100 parts by weight of component (A). An ultraviolet curable pressure-sensitive adhesive composition characterized by the above is provided, and the above-described problems can be solved.
That is, in the ultraviolet curable pressure-sensitive adhesive composition of the present invention, a predetermined non-hydrophilic (meth) acrylate monomer and a hydrogenated terpene resin are blended in a predetermined amount with respect to the hydrogenated polybutadiene skeleton urethane acrylate oligomer. Therefore, it is possible to effectively improve the compatibility between the components.
Therefore, the ultraviolet curable pressure-sensitive adhesive composition of the present invention can stably obtain a pressure-sensitive adhesive having excellent curability and excellent adhesive properties, transparency, and step following ability.
In the present invention, “(meth) acrylate” means both acrylate and methacrylate.
In the present invention, the “non-hydrophilic (meth) acrylate monomer” means a (meth) acrylate monomer having a water solubility (measurement temperature: 20 ° C.) of 50% by weight or less.
Moreover, the ultraviolet curable adhesive composition of this invention is a solvent-free type, and does not contain a solvent substantially.
More specifically, even when a solvent is included, the value is preferably 1% by weight or less with respect to the total amount (100% by weight) of the ultraviolet curable pressure-sensitive adhesive composition.

Moreover, in comprising the ultraviolet curable adhesive composition of this invention, the compounding quantity of isostearyl (meth) acrylate is 20-65 weight% with respect to the total amount (100 weight%) of (B) component. In addition to the value within the range, the blending amount of lauryl (meth) acrylate is preferably set to a value within the range of 20 to 70% by weight with respect to the total amount (100% by weight) of component (B).
By comprising in this way, the compatibility of each component can be improved more and both the sclerosis | hardenability of an ultraviolet curable adhesive composition and the adhesive characteristic of the adhesive obtained can be improved with good balance. As a result, the transparency and the step following ability of the pressure-sensitive adhesive obtained can be improved.

Moreover, in comprising the ultraviolet curable adhesive composition of this invention, while (B) component further contains isodecyl (meth) acrylate, the compounding quantity of the said isodecyl (meth) acrylate is the total amount of (B) component. It is preferable to set it as the value within the range of 10-30 weight% with respect to (100 weight%).
By comprising in this way, the compatibility of each component can further be improved and the sclerosis | hardenability of an ultraviolet curable adhesive composition and the adhesive characteristic of the obtained adhesive can be improved with good balance. As a result, the transparency and the step following ability of the pressure-sensitive adhesive obtained can be further improved.

Further, in constituting the ultraviolet curable pressure-sensitive adhesive composition of the present invention, the weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A) is set to a value within the range of 3,000 to 100,000. Is preferred.
By comprising in this way, the adhesive characteristic of the obtained adhesive can be improved effectively, maintaining the sclerosis | hardenability of an ultraviolet curable adhesive composition effectively.

Moreover, when comprising the ultraviolet curable adhesive composition of this invention, it is preferable to make the weight average molecular weight of the hydrogenated terpene resin as (C) component into the value within the range of 500-3,000.
By comprising in this way, the transparency and adhesive characteristic of the adhesive which are obtained can be improved more effectively, maintaining the sclerosis | hardenability of an ultraviolet curable adhesive composition effectively.

In constituting the ultraviolet curable pressure-sensitive adhesive composition of the present invention, the hydrogenated terpene resin as the component (C) is a fully hydrogenated terpene resin having a softening point in the range of 80 to 180 ° C. It is preferable.
By constituting in this way, while not only can effectively maintain the curability of the ultraviolet curable pressure-sensitive adhesive composition, the transparency and pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive can be improved more effectively, The heat resistance can also be improved.

Further, in constituting the ultraviolet curable pressure-sensitive adhesive composition of the present invention, the component (D) further contains a hydrophilic (meth) acrylate monomer, and the blending amount of the component (D) is changed to the component (A) 100. It is preferable to set it as the value within the range of 15-35 weight part with respect to a weight part.
By comprising in this way, the moisture resistance of the adhesive obtained can be improved and the outstanding anti-fogging effect can be acquired.
In the present invention, the “hydrophilic (meth) acrylate monomer” means a (meth) acrylate monomer whose solubility in water (measurement temperature: 20 ° C.) exceeds 50% by weight, and will be described later. The acrylamide compound as the component (E) to be used is not included.

Moreover, in comprising the ultraviolet curable adhesive composition of this invention, while further including an acrylamide compound as (E) component, the compounding quantity of the said (E) component is with respect to 100 weight part of (A) component. The value is preferably in the range of 3 to 12 parts by weight.
By comprising in this way, the moisture resistance of the adhesive which is obtained can further be improved, and the more outstanding anti-fogging effect can be acquired.

Further, in constituting the ultraviolet curable pressure-sensitive adhesive composition of the present invention, as the component (F), a photopolymerization initiator is further included, and the blending amount of the component (F) is adjusted to 100 parts by weight of the component (A). On the other hand, it is preferable to set it as the value within the range of 3-8 weight part.
By comprising in this way, the sclerosis | hardenability of an ultraviolet curable adhesive composition can be improved.

Another embodiment of the present invention is a pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer formed on the surface of the base material, wherein the pressure-sensitive adhesive layer is a hydrogenated polybutadiene skeleton as the component (A). An ultraviolet curable pressure-sensitive adhesive composition comprising a urethane acrylate oligomer, a non-hydrophilic (meth) acrylate monomer as component (B), and a hydrogenated terpene resin as component (C), wherein component (B) Contains isostearyl (meth) acrylate and lauryl (meth) acrylate, and the blending amount of component (B) is within the range of 95 to 205 parts by weight with respect to 100 parts by weight of component (A), and The ultraviolet curable adhesive composition which makes the compounding quantity of (C) component the value within the range of 45-95 weight part with respect to 100 weight part of (A) component is characterized by the above-mentioned. With adhesive sheet That.
That is, since the pressure-sensitive adhesive sheet of the present invention forms a pressure-sensitive adhesive layer using a predetermined ultraviolet curable pressure-sensitive adhesive composition, it can exhibit excellent pressure-sensitive adhesive properties, transparency, and step following ability. it can.

FIG. 1 is a diagram provided for explaining the relationship between the blending amount of a non-hydrophilic (meth) acrylate monomer, the curability of the ultraviolet curable pressure-sensitive adhesive composition, and the step following property of the pressure-sensitive adhesive obtained. FIG. 2 is used to explain the relationship between the compounding ratio of isostearyl (meth) acrylate and lauryl (meth) acrylate, the curability of the ultraviolet curable pressure-sensitive adhesive composition, and the step following property of the pressure-sensitive adhesive obtained. FIG. FIG. 3 is a diagram provided to explain the relationship between the blended amount of the hydrogenated terpene resin, the curability of the ultraviolet curable pressure-sensitive adhesive composition, and the step following property of the pressure-sensitive adhesive obtained.

[First Embodiment]
The first embodiment of the present invention includes a hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A), a non-hydrophilic (meth) acrylate monomer as the component (B), and a hydrogenated terpene as the component (C). An ultraviolet curable pressure-sensitive adhesive composition comprising a resin, wherein the component (B) contains isostearyl (meth) acrylate and lauryl (meth) acrylate, and the blending amount of the component (B) The value is within the range of 95 to 205 parts by weight with respect to 100 parts by weight, and the amount of component (C) is within the range of 45 to 95 parts by weight with respect to 100 parts by weight of component (A). It is an ultraviolet curable pressure-sensitive adhesive composition characterized by having a value.
Hereinafter, the components (A) to (C) that are the constituent requirements of the first embodiment will be specifically described.

1. Component (A): Hydrogenated polybutadiene skeleton urethane acrylate oligomer The ultraviolet curable pressure-sensitive adhesive composition of the present invention includes a hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A).
This is because the hydrogenated polybutadiene skeleton urethane acrylate oligomer has an acrylate portion containing a reactive double bond, and combined with the reactivity of the component (B) described later, an ultraviolet curable pressure-sensitive adhesive composition. This is because excellent ultraviolet curability can be imparted to the product.
In addition, by having a flexible polybutadiene skeleton portion, in combination with tackifying properties derived from the components (B) and (C) described later, excellent adhesive properties are imparted to the resulting adhesive. can do.
Furthermore, when the polybutadiene skeleton portion is hydrogenated, yellowing derived from urethane can be effectively suppressed, and excellent transparency can be imparted to the resulting pressure-sensitive adhesive.

(1) Kind Moreover, a hydrogenated polybutadiene frame urethane acrylate oligomer can be obtained by reaction of a hydrogenated polybutadiene frame polyol, an organic polyisocyanate compound, and hydroxyacrylate.

The kind of the hydrogenated polybutadiene skeleton polyol is not particularly limited, but is preferably a hydrogenated polybutadiene skeleton diol compound because it is easy to produce and relatively inexpensive.
In addition, the hydrogenation rate of the double bond contained in the hydrogenated polybutadiene skeleton is preferably 90% or more, and more preferably 95% or more.

  Moreover, as the organic polyisocyanate compound described above, non-yellowing type compounds such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and trimethylhexamethylene diisocyanate are preferable.

  Furthermore, as the hydroxy acrylate described above, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, caprolactone-modified 2-hydroxyethyl acrylate, and the like are preferable.

(2) Weight average molecular weight Moreover, it is preferable to make the weight average molecular weight of a hydrogenated polybutadiene frame | skeleton urethane acrylate oligomer into the value within the range of 3,000-100,000.
The reason for this is that by setting the weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer to a value within this range, while maintaining the curability of the ultraviolet curable adhesive composition effectively, This is because the adhesive properties can be effectively improved.
That is, when the weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer is less than 3,000, the curing rate when the ultraviolet curable pressure-sensitive adhesive composition is irradiated with ultraviolet rays is excessively increased, and the pressure-sensitive adhesive obtained This is because the adhesive properties may be significantly reduced. On the other hand, when the weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer exceeds 100,000, the curing rate when the ultraviolet curable adhesive composition is irradiated with ultraviolet rays is excessively decreased, and the resulting adhesive is obtained. This is because poor adhesion may easily occur between the base material as the formation target of the pressure-sensitive adhesive.
Therefore, the weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer is more preferably set to a value within the range of 5,000 to 25,000, and further preferably set to a value within the range of 8,000 to 20,000. preferable.
The weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer can be measured as a molecular weight in terms of polystyrene by gel permeation chromatography (GPC).

(3) Blending amount The blending amount of the hydrogenated polybutadiene skeleton urethane acrylate oligomer is set to a value within the range of 15 to 45% by weight with respect to the total amount (100% by weight) of the ultraviolet curable adhesive composition. It is preferable.
This is because when the blending amount is less than 15% by weight, the obtained pressure-sensitive adhesive becomes excessively brittle, and the adhesiveness to the substrate may be easily lowered. On the other hand, when the blending amount exceeds 45% by weight, the adhesive properties of the obtained adhesive may be easily deteriorated.
Therefore, the blending amount of the hydrogenated polybutadiene skeleton urethane acrylate oligomer is more preferably set to a value within the range of 20 to 40% by weight with respect to the total amount (100% by weight) of the ultraviolet curable adhesive composition. More preferably, the value is within the range of 24 to 35% by weight.

2. Component (B): Non-hydrophilic (meth) acrylate monomer (1) type The ultraviolet curable pressure-sensitive adhesive composition of the present invention comprises a non-hydrophilic (meth) acrylate monomer as component (B). .
The non-hydrophilic (meth) acrylate monomer includes isostearyl (meth) acrylate and lauryl (meth) acrylate.
The reason for this is that by including isostearyl (meth) acrylate and lauryl (meth) acrylate, the compatibility of each component is improved, and the curability of the UV-curable adhesive composition and the adhesive pressure of the resulting adhesive are increased. This is because the characteristics can be improved in a well-balanced manner.

That is, since isostearyl (meth) acrylate has excellent reactivity, combined with the reactivity of component (A), it has excellent ultraviolet curability for the ultraviolet curable pressure-sensitive adhesive composition. This is because it can be given.
On the other hand, because of its bulky three-dimensional structure, it is possible to impart predetermined flexibility to the resulting pressure-sensitive adhesive, and in combination with tackiness by the component (A) and the component (C) described later. Thus, it is possible to effectively improve the pressure-sensitive adhesive properties and the step following ability of the obtained pressure-sensitive adhesive.

However, when isostearyl (meth) acrylate is used alone as the non-hydrophilic (meth) acrylate monomer, it becomes difficult to sufficiently compatibilize component (C) with the UV-curable adhesive composition. It becomes difficult to obtain sufficient adhesive properties and step following ability.
In this respect, by containing lauryl (meth) acrylate as another non-hydrophilic (meth) acrylate monomer, while improving the curability of the ultraviolet curable pressure-sensitive adhesive composition, (C ) The compatibility of the components can be effectively improved, the adhesive properties and the step following ability of the resulting pressure-sensitive adhesive can be effectively improved, and the transparency can also be improved.
In addition, isostearyl acrylate is more preferable among isostearyl (meth) acrylates, and more specifically, isostearyl acrylate having a structure represented by the following formula (1) is more preferable.
Of lauryl (meth) acrylates, lauryl acrylate is more preferable, and more specifically, lauryl acrylate having a structure represented by the following formula (2) is more preferable.

It is also preferable to further include a non-hydrophilic (meth) acrylate monomer other than the above-mentioned isostearyl (meth) acrylate and lauryl (meth) acrylate.
For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) Alkyl (meth) acrylates such as acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, n-stearyl (meth) acrylate, tridecyl (meth) acrylate; cyclohexyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (Meth) acrylate, norbornanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) a Relate, cyclic alkyl (meth) acrylates such as dicyclopentanyloxyethyl (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate; ethoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meta ) Alkoxyalkyl (meth) acrylates such as acrylate, 2-methoxyethoxyethyl (meth) acrylate, 2-ethoxyethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate; methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) Alkoxy (poly) alkylene glycol (meth) acrylates such as acrylate and methoxydipropylene glycol (meth) acrylate; N, N-dimethyl Minoechiru (meth) acrylate, N, such as N- diethylaminoethyl (meth) acrylate N, etc. N- dialkylaminoalkyl (meth) acrylate.

Among these, it is particularly preferable to further contain isodecyl (meth) acrylate.
The reason for this is that by further including isodecyl (meth) acrylate, it effectively holds between isostearyl (meth) acrylate and lauryl (meth) acrylate, further improving the compatibility of each component, and UV curable This is because both the curability of the pressure-sensitive adhesive composition and the pressure-sensitive adhesive properties of the pressure-sensitive adhesive obtained can be improved in a well-balanced manner, and as a result, the transparency and the step following property of the pressure-sensitive adhesive obtained can be further improved. is there.
In addition, isodecyl acrylate is more preferable among isodecyl (meth) acrylates, and more specifically, isodecyl acrylate having a structure represented by the following formula (3) is more preferable.

(2) Compounding quantity Moreover, it is characterized by making the compounding quantity of a non-hydrophilic (meth) acrylate monomer into the value within the range of 95-205 weight part with respect to 100 weight part of (A) component.
The reason for this is that when the blending amount is less than 95 parts by weight, the compatibility with the component (A) becomes insufficient, and the curability of the ultraviolet curable pressure-sensitive adhesive composition and the pressure-sensitive adhesive properties of the obtained pressure-sensitive adhesive are high. This is because it may become excessively unstable. On the other hand, if the blending amount exceeds 205 parts by weight, the overall compatibility is lowered, the resulting adhesive becomes brittle, and the step following ability may be excessively lowered.
Therefore, it is more preferable that the blending amount of the non-hydrophilic (meth) acrylate monomer is set to a value within the range of 115 to 185 parts by weight with respect to 100 parts by weight of the component (A), and a range of 125 to 175 parts by weight. More preferably, the value is within the range.

Next, the relationship between the blending amount of the non-hydrophilic (meth) acrylate monomer and the curability of the ultraviolet curable pressure-sensitive adhesive composition and the step following property of the pressure-sensitive adhesive obtained will be described with reference to FIG.
That is, in FIG. 1, the horizontal axis represents the blending amount (parts by weight) of the non-hydrophilic (meth) acrylate monomer as the component (B) with respect to 100 parts by weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A). The left vertical axis is a characteristic curve A using the total light transmittance (evaluation point), which is one of the curability indexes as well as the transparency, and the right vertical axis is the characteristic using the step following property (evaluation point). Curve B is shown.

Here, the curability is an ultraviolet curable pressure-sensitive adhesive composition relating to whether or not the coating layer made of the ultraviolet curable pressure-sensitive adhesive composition is rapidly cured from the lower end to the upper end in the film thickness direction by irradiation with a predetermined amount of ultraviolet light. This property is a property that greatly depends on the compatibility between the components constituting the ultraviolet curable pressure-sensitive adhesive composition.
In addition, the curability is a property that is a prerequisite for the properties of the pressure-sensitive adhesive obtained from the UV-curable pressure-sensitive adhesive composition, such as pressure-sensitive adhesive properties and transparency, and is therefore closely related to the properties of these pressure-sensitive adhesives. It becomes a characteristic.
In this regard, in the ultraviolet curable pressure-sensitive adhesive composition of the present invention, the total light transmittance, which is a characteristic of the obtained pressure-sensitive adhesive, and the curability of the ultraviolet curable pressure-sensitive adhesive composition are relatively strong from experience. Correlations have been found.
Therefore, in the characteristic curve A, the total light transmittance is adopted as an index of curability.

On the other hand, the step following property is a composite property in which a plurality of factors such as adhesive properties and flexibility of the adhesive are intertwined.
In addition, since flexibility, which is one of the factors of step followability, is a property that is contrary to the above-described curability, it is known that both the curability and the step followability are generally reciprocal properties that are difficult to achieve at the same time. It has been.
The evaluation points for the total light transmittance and the step following property are obtained by evaluating the total light transmittance and the step following property described in the examples, and numerically expressing the obtained results according to the following criteria.
In addition, details, such as a composition of an ultraviolet curable adhesive composition, apply to Example 1.

(Total light transmittance)
4: The obtained total light transmittance is a value of 90% or more 3: The obtained total light transmittance is a value less than 85 to 90% 2: The obtained total light transmittance is 80 to 85% Is less than 1: the total light transmittance obtained is less than 80%

(Step following capability)
4: Bubbles are not observed 3: Bubbles are observed on one side among the four sides constituting the frame 2: Bubbles are observed on two sides among the four sides constituting the frame 1: Four sides constituting the frame Inside, bubbles are observed on more than 3 sides

First, from the characteristic curve A, it is understood that there is an optimum range for the blending amount of the component (B) when improving the total light transmittance, which is also one of the curability indicators.
That is, it is understood that the evaluation point of the total light transmittance once increases and then decreases as the blending amount of the component (B) increases.
More specifically, if the blending amount of the component (B) is a value within the range of 95 to 205 parts by weight, the evaluation point of the total light transmittance can be stably set to a value of 3 or more, In other numerical ranges, it is understood that it becomes difficult to stably maintain the evaluation point of total light transmittance at a value of 3 or more, and it is difficult to maintain excellent total light transmittance. .

Also, the characteristic curve B is the same as the characteristic curve A, and if the blending amount of the component (B) is a value within the range of 95 to 205 parts by weight, the step followability evaluation point is stably 3 or more. Even if the value is less than 3 or a value below 3, it can be set to a value in the vicinity of 3, while in other numerical ranges, the step followability evaluation point is stably set to a value of 3 or more, or a value in the vicinity of 3 It is understood that it becomes difficult to maintain.
Therefore, by setting the blending amount of the non-hydrophilic (meth) acrylate monomer as (B) to a value within the range of 95 to 205 parts by weight with respect to 100 parts by weight of component (A), not only transparency It is understood that the total light transmittance, which is also one of the curability indicators, and the step following ability, which is a reciprocal property of curability, can be effectively improved.

Further, the blending amount of isostearyl (meth) acrylate is set to a value within the range of 20 to 65 wt% with respect to the total amount (100 wt%) of the component (B), and blending of lauryl (meth) acrylate The amount is preferably set to a value in the range of 20 to 70% by weight with respect to the total amount (100% by weight) of the component (B).
The reason for this is that isostearyl (meth) acrylate and lauryl (meth) acrylate are mixed and used in the above-mentioned proportions with respect to the total amount of component (B), thereby improving the compatibility between the components. Thus, both the curability of the ultraviolet curable pressure-sensitive adhesive composition and the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive can be improved in a balanced manner, and the transparency and the step following property of the resulting pressure-sensitive adhesive are also improved. Because it can.

  That is, if the blending amount of isostearyl (meth) acrylate is less than 20% by weight with respect to the total amount of component (B), the curability of the UV curable pressure-sensitive adhesive composition may be excessively lowered. It is. On the other hand, when the blending amount of isostearyl (meth) acrylate exceeds 65% by weight with respect to the total amount of component (B), the component (C) described below is sufficient for the ultraviolet curable pressure-sensitive adhesive composition. This is because it is difficult to achieve compatibility with the resin, and it may be difficult to obtain sufficient adhesive properties and step following ability, and transparency may be easily lowered.

  Moreover, when the compounding quantity of lauryl (meth) acrylate becomes a value less than 20 weight% with respect to the total amount of (B) component, (C) component is fully compatible with an ultraviolet curable adhesive composition. This is because it may be difficult to impart sufficient adhesive properties and level difference followability to the obtained adhesive, and transparency may be easily lowered. On the other hand, if the amount of lauryl (meth) acrylate exceeds 70% by weight with respect to the total amount of component (B), the curability of the UV curable pressure-sensitive adhesive composition may be excessively lowered. It is.

Therefore, the blending amount of isostearyl (meth) acrylate is more preferably set to a value in the range of 25 to 55% by weight with respect to the total amount (100% by weight) of component (B), and 30 to 50% by weight. More preferably, the value is within the range of%.
Moreover, it is more preferable to make the compounding quantity of lauryl (meth) acrylate into the value within the range of 25 to 65 weight% with respect to the total amount (100 weight%) of (B) component, and 30 to 60 weight% It is more preferable to set the value within the range.
From the same point of view, the blending ratio (weight ratio) of isostearyl (meth) acrylate: lauryl (meth) acrylate is preferably set to a value within the range of 30:70 to 60:40, and 35:65 to 55. : It is more preferable to set it as the value within the range of 45, and it is still more preferable to set it as the value within the range of 40: 60-50: 50.

Next, with reference to FIG. 2, the relationship between the compounding ratio of isostearyl (meth) acrylate and lauryl (meth) acrylate, the curability of the UV curable adhesive composition and the step following ability of the resulting adhesive will be described. To do.
That is, in FIG. 2, the horizontal axis represents the blending amount (wt%) of isostearyl (meth) acrylate with respect to the total amount (100 wt%) of component (B), and the left vertical axis represents not only transparency but also curability. A characteristic curve A that employs the total light transmittance (evaluation point), which is also one of the indicators, and a characteristic curve B that employs a step following property (evaluation point) are shown on the right vertical axis.
In preparing these characteristic curves, the component (B) was composed only of isostearyl (meth) acrylate and lauryl (meth) acrylate. Therefore, the remainder of the isostearyl (meth) acrylate in the component (B) becomes lauryl (meth) acrylate.
Further, the criteria for the evaluation points of the total light transmittance and the step following ability are the same as those in the case of the characteristic curve shown in FIG. 1, and the details of the composition of the ultraviolet curable pressure-sensitive adhesive composition are described in Example 1. Follow.

First, from the characteristic curve A, there is an optimum range for the compounding ratio of isostearyl (meth) acrylate and lauryl (meth) acrylate when improving the total light transmittance, which is also one of the indicators of curability. It is understood that
That is, if the blending amount of isostearyl (meth) acrylate is a value within the range of 30 to 60% by weight, the evaluation point of the total light transmittance can be stably set to a value close to 4, while other than that In this numerical range, it is understood that it is difficult to stably maintain the evaluation point of total light transmittance at a value near 4 and it is difficult to maintain excellent total light transmittance.

Also, the characteristic curve B is the same as the characteristic curve A. If the blending amount of isostearyl (meth) acrylate is a value within the range of 30 to 60% by weight, the step followability evaluation point can be stably set. Even if it is a value of 3 or more, or even if it is less than 3, it can be set to a value in the vicinity of 3, while in other numerical ranges, the step followability evaluation point is stable to a value of 3 or more or in the vicinity of 3 It is understood that it becomes difficult to maintain the value.
Therefore, by setting the compounding ratio (weight ratio) of isostearyl (meth) acrylate: lauryl (meth) acrylate to a value within the range of 30:70 to 60:40, not only transparency but also a curable index 1 It is understood that the total light transmittance, which is one, and the step following ability, which is a curable conflicting characteristic, can be effectively improved.

Moreover, when it further contains non-hydrophilic (meth) acrylate monomers other than isostearyl (meth) acrylate and lauryl (meth) acrylate, especially isodecyl (meth) acrylate, the blending amount is the total amount of component (B) It is preferable to set it as the value within the range of 10-30 weight% with respect to (100 weight%).
The reason for this is that, by using such other non-hydrophilic (meth) acrylate monomers mixed in the above-described proportion with respect to the total amount of component (B), the compatibility between the components is further improved, Both the curability of the UV curable pressure-sensitive adhesive composition and the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive can be improved in a well-balanced manner, and as a result, the transparency and step following ability of the resulting pressure-sensitive adhesive can be further improved. This is because it can.

That is, when the blending amount of the other non-hydrophilic (meth) acrylate monomer is less than 10% by weight with respect to the total amount of the component (B), the compatibility between the components is excessively decreased, and UV curing is performed. This is because the curability of the mold pressure-sensitive adhesive composition may decrease. On the other hand, if the amount of other non-hydrophilic (meth) acrylate monomer exceeds 30% by weight with respect to the total amount of component (B), the curability of the UV curable pressure-sensitive adhesive composition increases excessively. This is because the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive may deteriorate.
Therefore, when the non-hydrophilic (meth) acrylate monomer other than isostearyl (meth) acrylate and lauryl (meth) acrylate is further included, the blending amount is based on the total amount (100% by weight) of the component (B). Thus, the value is more preferably in the range of 12 to 25% by weight, and further preferably in the range of 14 to 20% by weight.
In other words, the value is preferably in the range of 8 to 35% by weight with respect to the total amount (100% by weight) of isostearyl (meth) acrylate and lauryl (meth) acrylate, The value is more preferably in the range of ˜30% by weight, and further preferably in the range of 16-25% by weight.

3. Component (C): Hydrogenated terpene resin The ultraviolet curable pressure-sensitive adhesive composition of the present invention includes a hydrogenated terpene resin as the component (C).
The reason for this is that the hydrogenated terpene resin is excellent in compatibility with the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A), while not inhibiting the ultraviolet curing reaction of the ultraviolet curable pressure-sensitive adhesive composition, This is because the curability can be effectively maintained.
And since it can be uniformly distributed as a thermoplastic component in the obtained pressure-sensitive adhesive, it can impart excellent pressure-sensitive adhesive properties while contributing to the flexibility of the pressure-sensitive adhesive, and thus provides excellent step following ability. can do.
Furthermore, it contributes to the improvement of heat resistance and can impart excellent transparency to the resulting pressure-sensitive adhesive by being hydrogenated.

(1) Kinds As hydrogenated terpene resins in the present invention, terpene resins such as α-pinene, β-pinene and dipentene, terpene resins such as aromatic modified terpene resins and terpene phenol resins are hydrogenated. Means things.
More specifically, terpene phenol resin hydrides such as YS Polystar UH115 manufactured by Yasuhara Chemical Co., Ltd., terpene resin hydrides such as Clearon P150, Clearon P135, Clearon P125, Clearon P115, Clearon P105, Clearon P85, Clearon M125, Aromatic modified terpene resin hydrides such as Clearon M115, Clearon M105, Clearon K100, Clearon K4100 and the like can be mentioned.

The hydrogenated terpene resin is preferably a completely hydrogenated terpene resin.
This is because a completely hydrogenated terpene resin is excellent in yellowing resistance, and thus the transparency of the resulting pressure-sensitive adhesive can be further improved.
The fully hydrogenated terpene resin means a terpene resin in which hydrogen is added to all unsaturated double bonds contained in the terpene resin.
Moreover, among the hydrogenated terpene resins described above, the Clearon P series corresponds to a completely hydrogenated terpene resin.

(2) Weight average molecular weight Moreover, it is preferable to make the weight average molecular weight of hydrogenated terpene resin into the value within the range of 500-3,000.
The reason for this is that by setting the weight average molecular weight of the hydrogenated terpene resin to a value within such a range, the transparency of the resulting pressure-sensitive adhesive can be maintained while effectively maintaining the curability of the UV-curable pressure-sensitive adhesive composition. This is because the adhesive properties can be improved more effectively.
That is, when the weight average molecular weight of the hydrogenated terpene resin is less than 500, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, and the pressure-sensitive adhesive properties of the obtained pressure-sensitive adhesive may be excessively lowered. is there. On the other hand, when the weight average molecular weight of the hydrogenated terpene resin exceeds 3,000, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably lowered, and the transparency in the obtained pressure-sensitive adhesive may be excessively lowered. Because there is.
Therefore, the weight average molecular weight of the hydrogenated terpene resin is more preferably set to a value within the range of 600 to 2,000, and further preferably set to a value within the range of 650 to 1,000.
The weight average molecular weight of the hydrogenated terpene resin can be measured as a molecular weight in terms of polystyrene by gel permeation chromatography (GPC).

(3) Softening point Moreover, it is preferable to make the softening point of hydrogenated terpene resin into the value within the range of 80-180 degreeC.
This is because when the softening point of the hydrogenated terpene resin is less than 80 ° C., the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, and the pressure-sensitive adhesive properties and heat resistance of the resulting pressure-sensitive adhesive are excessively lowered. This is because there are cases. On the other hand, when the softening point of the hydrogenated terpene resin exceeds 180 ° C., the curability of the UV curable pressure-sensitive adhesive composition is significantly reduced, and the transparency and pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive are excessively unstable. This is because there may be cases.
Therefore, the softening point of the hydrogenated terpene resin is more preferably set to a value within the range of 100 to 170 ° C, and further preferably set to a value within the range of 120 to 160 ° C.

(4) Compounding quantity Moreover, the compounding quantity of hydrogenated terpene resin is made into the value within the range of 45-95 weight part with respect to 100 weight part of (A) component, It is characterized by the above-mentioned.
The reason for this is that when the blending amount is less than 45 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive are remarkably lowered, and the pressure-sensitive adhesive becomes brittle. This is because the step following ability may be excessively lowered. On the other hand, when the blending amount exceeds 95 parts by weight, the curability of the UV curable pressure-sensitive adhesive composition is remarkably lowered, the transparency of the obtained pressure-sensitive adhesive is remarkably lowered, and the pressure-sensitive adhesive property is excessively poor. This is because it may become stable.
Therefore, the blending amount of the hydrogenated terpene resin is more preferably set to a value in the range of 55 to 85 parts by weight with respect to 100 parts by weight of the component (A), and a value in the range of 60 to 75 parts by weight More preferably.

Next, the relationship between the blending amount of the hydrogenated terpene resin, the curability of the ultraviolet curable pressure-sensitive adhesive composition, and the step following property of the obtained pressure-sensitive adhesive will be described with reference to FIG.
That is, in FIG. 3, the horizontal axis represents the blending amount (parts by weight) of the hydrogenated terpene resin as the component (C) with respect to 100 parts by weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A). Shows a characteristic curve A that takes the total light transmittance (evaluation point), which is one of the indicators of curability as well as transparency, and a characteristic curve B that takes the step following ability (evaluation point) on the right vertical axis. It is.
In addition, the reference | standard of the evaluation point of the total light transmittance and level | step difference followability, etc. are the same as that of the case of the characteristic curve shown in FIG. 1, The details about a composition etc. of an ultraviolet curable adhesive composition are in Example 1. Follow.

First, from the characteristic curve A, it is understood that there is an optimum range for the blending amount of component (B) when improving the total light transmittance, which is one of the indicators of curability as well as transparency. Is done.
That is, it is understood that the evaluation point of the total light transmittance once increases and then decreases as the blending amount of the component (B) increases.
More specifically, if the blending amount of the component (B) is a value within the range of 45 to 95 parts by weight, the evaluation point of the total light transmittance can be stably set to a value near 4. In other numerical ranges, it is understood that it becomes difficult to stably maintain the evaluation point of total light transmittance at a value near 4 and to maintain excellent total light transmittance. .

Further, the characteristic curve B is the same as the characteristic curve A, and if the blending amount of the component (B) is a value within the range of 45 to 95 parts by weight, the step followability evaluation point is stably 3 or more. Even if the value is less than 3 or a value below 3, it can be set to a value in the vicinity of 3, while in other numerical ranges, the step followability evaluation point is stably set to a value of 3 or more, or a value in the vicinity of 3 It is understood that it becomes difficult to maintain.
Therefore, by setting the blending amount of the hydrogenated terpene resin as (C) to a value within the range of 45 to 95 parts by weight with respect to 100 parts by weight of the component (A), not only transparency but also an index of curability It is understood that the total light transmittance, which is also one of the above, and the step following ability, which is a curable conflicting characteristic, can be effectively improved.

4). (D) component: hydrophilic (meth) acrylate monomer Moreover, it is preferable that the ultraviolet curable adhesive composition of this invention contains a hydrophilic (meth) acrylate monomer as (D) component.
The reason for this is that by including a hydrophilic (meth) acrylate monomer, the moisture resistance of the resulting pressure-sensitive adhesive can be improved and an excellent antifogging effect can be obtained.

(1) Kind Moreover, as a kind of hydrophilic (meth) acrylate monomer, although it does not restrict | limit in particular, For example, (meth) acrylic acid, ethyl carbitol (meth) acrylate, 2-hydroxyethyl (meth) Examples include acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,3-butanediol mono (meth) acrylate, and 1,4-butanediol mono (meth) acrylate.
Among them, it is particularly preferable to use 4-hydroxybutyl acrylate.
The reason for this is that if it is 4-hydroxybutyl acrylate, the moisture resistance of the adhesive is more effectively maintained while effectively maintaining the curability of the UV-curable adhesive composition and the adhesive properties of the resulting adhesive. This is because it can be improved.

(2) Compounding quantity Moreover, it is preferable to make the compounding quantity of a hydrophilic (meth) acrylate monomer into the value within the range of 15-35 weight part with respect to 100 weight part of (A) component.
The reason for this is that when the blending amount is less than 15 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably lowered, and the moisture resistance of the obtained pressure-sensitive adhesive may be excessively lowered. . On the other hand, when the blending amount exceeds 35 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, and the pressure-sensitive adhesive properties of the obtained pressure-sensitive adhesive may become excessively unstable. is there.
Accordingly, the blending amount of the hydrophilic (meth) acrylate monomer is more preferably set to a value within the range of 18 to 30 parts by weight with respect to 100 parts by weight of the component (A), and within a range of 20 to 25 parts by weight. More preferably, the value of

5. (E) component: acrylamide compound Moreover, it is preferable that the ultraviolet curable adhesive composition of this invention contains an acrylamide compound as (E) component.
The reason for this is that by including an acrylamide compound, the moisture resistance of the resulting pressure-sensitive adhesive can be further improved, and a more excellent antifogging effect can be obtained.

(1) Kind In addition, the kind of acrylamide compound is not particularly limited. For example, diacetone acrylamide, isobutoxymethyl acrylamide, N, N-dimethyl acrylamide, t-octyl acrylamide, N, N-diethyl Examples include acrylamide, N, N-butoxymethylacrylamide, N, N-dimethylaminopropylacrylamide, acryloylmorpholine, and the like.
Among these, it is particularly preferable to use N, N-diethylacrylamide.
The reason for this is that if N, N-diethylacrylamide is used, the moisture resistance of the adhesive is more effective while effectively maintaining the curability of the UV-curable adhesive composition and the adhesive properties of the resulting adhesive. This is because it can be improved.

(2) Compounding quantity Moreover, it is preferable to make the compounding quantity of an acrylamide compound into the value within the range of 3-12 weight part with respect to 100 weight part of (A) component.
The reason for this is that when the blending amount is less than 3 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, and the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive may become excessively unstable. It is. On the other hand, when the blending amount exceeds 12 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably lowered, and the moisture resistance in the obtained pressure-sensitive adhesive may be excessively lowered.
Therefore, the blending amount of the acrylamide compound is more preferably 4 to 10 parts by weight with respect to 100 parts by weight of the component (A), more preferably 5 to 8 parts by weight. Is more preferable.

6). Component (F): Photopolymerization initiator The ultraviolet curable pressure-sensitive adhesive composition of the present invention preferably contains a photopolymerization initiator as the component (F).
This is because the curability of the ultraviolet curable pressure-sensitive adhesive composition can be improved by including a photopolymerization initiator.

(1) Kind Moreover, as a kind of photoinitiator, especially if a radical generate | occur | produces with an ultraviolet-ray and the radical carries out a polymerization reaction of photocurable components, such as (A) component and (B) component, it will restrict | limit. For example, benzyl dimethyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethane-1-one; oligo [2-hydroxy-2-methyl-1- [4- (1 -Methyl vinyl) phenyl] propanone], α-hydroxy ketone compounds such as 1-hydroxycyclohexyl phenyl ketone; 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2- Α-aminoketone compounds such as benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; diphenyl (2,4,6- Acylphosphine oxide-based compounds such as limethylbenzoyl) phosphine oxide; 1- [4- (4-benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfonyl) propan-1-one A metallocene compound such as bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxypropoxy) 3,4-dimethyl-9H-thioxanthone-9-one-mesochloride, etc. And thioxanthone compounds.
Among them, it is particularly preferable to use an acyl phosphine oxide compound.
This is because the acyl phosphine oxide-based compound has an appropriate curing rate, can effectively maintain the adhesive properties of the resulting adhesive, and is excellent in weather resistance.

Moreover, it is preferable to make the compounding quantity of a photoinitiator into the value within the range of 3-8 weight part with respect to 100 weight part of (A) component.
The reason for this is that when the blending amount is less than 3 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably lowered, and the pressure-sensitive adhesive properties of the obtained pressure-sensitive adhesive may be remarkably lowered. On the other hand, when the blending amount exceeds 8 parts by weight, the curability of the ultraviolet curable pressure-sensitive adhesive composition is remarkably increased, the resulting pressure-sensitive adhesive becomes brittle, and the step following ability may be excessively lowered. Because.
Therefore, the blending amount of the photopolymerization initiator is more preferably set to a value in the range of 3.5 to 6 parts by weight with respect to 100 parts by weight of the component (A).

7). Other Additives The ultraviolet curable pressure-sensitive adhesive composition of the present invention may further contain other additives than the above-described components (A) to (F) as necessary.
Such other additives are not particularly limited, and are plasticizers, surface lubricants, leveling agents, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, flame retardants. And antistatic agents.

[Second Embodiment]
2nd Embodiment of this invention is an adhesive sheet containing a base material and the adhesive layer formed in the said base material surface, Comprising: An adhesive layer is hydrogenated polybutadiene frame | skeleton as (A) component An ultraviolet curable pressure-sensitive adhesive composition comprising a urethane acrylate oligomer, a non-hydrophilic (meth) acrylate monomer as component (B), and a hydrogenated terpene resin as component (C), wherein component (B) Contains isostearyl (meth) acrylate and lauryl (meth) acrylate, and the blending amount of component (B) is within the range of 95 to 205 parts by weight with respect to 100 parts by weight of component (A), and The ultraviolet curable adhesive composition which makes the compounding quantity of (C) component the value within the range of 45-95 weight part with respect to 100 weight part of (A) component is characterized by the above-mentioned. With adhesive sheet That.
Hereinafter, the adhesive sheet according to the second embodiment of the present invention will be specifically described.

1. Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet of the present invention is formed by applying the ultraviolet curable pressure-sensitive adhesive composition described above to a substrate to form a coating layer, and then irradiating with ultraviolet rays to cure the coating layer. Can be obtained.
Further, from the viewpoint of maintaining transparency, the thickness of the pressure-sensitive adhesive layer is preferably set to a value in the range of 20 to 500 μm, more preferably set to a value in the range of 30 to 400 μm, and 50 to 300 μm. More preferably, the value is within the range.
The details of the ultraviolet curable pressure-sensitive adhesive composition have been described as the first embodiment, and thus are omitted.

2. Base Material Examples of the base material include a glass base material, various plastic base materials, a metal base material, a ceramic base material, and a rubber base material.
Specifically, films made of acrylic resin, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, modified polyphenylene ether, polyether nitrile, polyethylene terephthalate, cycloolefin polymer, triacetyl cellulose, antireflection film, antifouling film, touch panel A transparent conductive film or the like to be used can be used.
The base material in the present invention includes a release film having a release treatment surface on one side or both sides.

3. Production Method The pressure-sensitive adhesive sheet of the present invention is produced by applying an ultraviolet curable pressure-sensitive adhesive composition to the substrate described above to form an application layer, and then irradiating the ultraviolet ray to cure the application layer. be able to.
The method of applying the UV curable adhesive composition is not particularly limited, but includes a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater, direct coater. An application method using the above is mentioned.

In addition, the ultraviolet irradiation method is not particularly limited, but the ultraviolet ray may be irradiated from one substrate side in a state where the coating layer is sandwiched between two substrates (including a release film) The layer may be provided on one release film whose both surfaces are release treatment surfaces, and ultraviolet rays may be irradiated from the coating layer side or from the release film side.
In the latter embodiment, it is preferable to wind the obtained pressure-sensitive adhesive sheet in a roll shape and protect the exposed surface of the pressure-sensitive adhesive layer with the back surface of the release film.
As the irradiation condition of the ultraviolet ray is preferably set to a value within the range of the lamp peak intensity of 200~300mW / cm ^2, the integrated quantity of light to a value within the range of 800~1,200mJ / cm ² preferable.

4). Applications The pressure-sensitive adhesive sheet of the present invention, for example, in a liquid crystal touch panel, a plastic substrate, a flexible printed substrate, a glass substrate, or a substrate obtained by depositing ITO, which is a transparent conductive material, is bonded to these substrates. Can be used for applications.
Moreover, in a liquid crystal display, the use which bonds the transparent base material which consists of glass, plastics, etc., and the polarizing plate which comprises the outermost part of a liquid crystal panel, the transparent protective base material which consists of glass, plastics, etc., and a liquid crystal panel It can also be used as a gap clear for filling the gaps between the two.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples without a particular reason.

[Example 1]
1. Preparation of UV curable pressure-sensitive adhesive composition The following composition was placed in a container equipped with a stirrer and then mixed until uniform using a stirrer to obtain a UV curable pressure-sensitive adhesive composition.
In addition, the compounding quantity in the following is the value converted into solid content.
(A) Hydrogenated polybutadiene skeleton urethane acrylate oligomer 100 parts by weight (B1) Isostearyl acrylate 54 parts by weight (B2) Lauryl acrylate 72 parts by weight (B3) Isodecyl acrylate 25 parts by weight (C) Hydrogenated terpene resin 72 parts by weight ( D) 4-hydroxybutyl acrylate 25 parts by weight (E) N, N-diethylacrylamide 7 parts by weight (F) photopolymerization initiator 5 parts by weight

As the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A), a commercially available product (weight average molecular weight: 14,000, hydrogenation rate: 97%) was used.
The (B1) component isostearyl acrylate has the structure represented by the above-described formula (1), and the (B2) component lauryl acrylate is represented by the above-described formula (2). As the isodecyl acrylate as the component (B3), a structure represented by the above formula (3) was used.
As the hydrogenated terpene resin as component (C), a commercially available product (weight average molecular weight: 750, softening point: 150 ° C., hydrogenation rate: 100%) was used.
In addition, as the photopolymerization initiator that is the component (F), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (manufactured by BASF Corporation, Lucillin TPO) was used.

2. Manufacture of pressure-sensitive adhesive sheet The film thickness of the pressure-sensitive adhesive layer after irradiation with ultraviolet rays using a casting knife on the release-treated surface of a release-treated polyester film having a thickness of 25 μm (hereinafter referred to as “release film”). The ultraviolet curable pressure-sensitive adhesive composition was applied to a thickness of 175 μm to form a coating layer.
Next, the obtained coating layer was cured by irradiating with ultraviolet rays under the following ultraviolet curing conditions to obtain an adhesive sheet obtained by laminating an adhesive layer having a film thickness of 175 μm on the release film.

(UV curing conditions)
Irradiator: GS Yuasa Lighting Co., Ltd., CS-60
Metal halide lamp: 120W / cm (2 lights type)
Lamp peak intensity: 250 mW / cm ²
Integrated light quantity: 1,000 mJ / cm ²

3. Evaluation of Adhesive Sheet (1) Adhesive Properties (1) -1 Adhesive Force The exposed surface of the obtained adhesive sheet is bonded to an untreated polyester film having a thickness of 125 μm (hereinafter referred to as “base film”). Then, this was cut | judged to 25 mm width, the peeling film was peeled, and it was set as the test piece.
Next, the surface of the exposed pressure-sensitive adhesive layer in the obtained test piece was attached by reciprocating a 2 kg roll once with respect to a glass plate as an adherend.
Next, 24 hours after the pasting, the pressure-sensitive adhesive strength of the pressure-sensitive adhesive sheet was measured by a tensile test in a 180 ° direction at a peeling rate of 300 mm / min in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH according to JIS-Z0237. N / 25 mm) and measured against the following criteria. The obtained results are shown in Table 1.
A: The obtained adhesive force is a value of 30 N / 25 mm or more. O: The obtained adhesive force is a value of less than 20-30 N / 25 mm. Δ: The obtained adhesive force is a value of less than 10-20 N / 25 mm. X: the obtained adhesive strength is less than 10 N / 25 mm

(1) -2 Heat-resistant retention strength After the exposed surface of the obtained pressure-sensitive adhesive sheet was bonded to a base film, it was cut into 25 mm length and 50 mm width, and the release film was peeled to obtain a test piece.
Next, the surface of the exposed pressure-sensitive adhesive layer in the obtained test piece was attached by reciprocating a 2 kg roll once with respect to a glass plate as an adherend.
Next, with respect to the test piece attached to the glass plate in the vertical direction in an atmosphere at a temperature of 80 ° C., a load of 1 kg is applied in the direction of 0 ° (shear direction) with respect to the glass plate, and the position of the test piece The deviation was measured and evaluated according to the following criteria. The obtained results are shown in Table 1.
A: No deviation is observed after 24 hours. O: A deviation of less than 2 mm is observed after 24 hours. Δ: A deviation of 2 mm or more is observed after 24 hours. X: A drop of the test piece is observed after 24 hours.

(2) Transparency (2) -1 Total light transmittance The obtained pressure-sensitive adhesive sheet was cut into a width of 25 mm, and the release film was peeled off to obtain a test piece.
Next, the surface of the exposed pressure-sensitive adhesive layer in the obtained test piece was attached by reciprocating a 2 kg roll once with respect to a glass plate as an adherend.
Next, in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH, the total light transmittance (%) is measured by Haze Meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH2000 (D65 light source)) according to JIS-K7361-1. Was measured and evaluated against the following criteria. The obtained results are shown in Table 1.
A: The obtained total light transmittance is a value of 90% or more. B: The obtained total light transmittance is a value less than 85 to 90%. Δ: The obtained total light transmittance is 80 to 85%. Less than x: The obtained total light transmittance is less than 80%

(2) -2 Whitening resistance After the exposed surface of the obtained pressure-sensitive adhesive sheet was bonded to a base film, it was cut into a length of 70 mm and a width of 60 mm, and the release film was peeled off to obtain a test piece.
Next, the surface of the exposed pressure-sensitive adhesive layer in the obtained test piece was attached by reciprocating a 2 kg roll once with respect to the slide glass as the adherend.
Next, in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH, haze was measured by Haze Meter (Nippon Denshoku Industries Co., Ltd., NDH2000 (D65 light source)) according to JIS-K7136. Value.
Next, the slide glass with the test piece attached is left in an atmosphere of temperature 85 ° C. and humidity 85% RH for 72 hours, and after 10 minutes from taking out, the haze is measured under the same measurement conditions as the initial value. This value was regarded as the durability value and evaluated in accordance with the following criteria. The obtained results are shown in Table 1.
A: The obtained durability value—the value of the initial value is less than 0.2 ○: The obtained durability value—the value of the initial value is a value of less than 0.2 to 1.0 Δ: Obtained Endurance value-initial value is a value less than 1.0 to 3.0 x: obtained endurance value-initial value is 3.0 or more

(3) Level followability After the exposed surface of the obtained pressure-sensitive adhesive sheet was bonded to a base film, it was cut into a length of 70 mm and a width of 60 mm, and the release film was peeled to obtain a test piece.
Next, a rectangular frame having a thickness (step difference) of 60 μm, a width of 6 mm, a length of 60 mm, and a width of 45 mm was printed on the glass plate using an ultraviolet curable ink and cured.
Next, the surface of the exposed adhesive layer in the obtained test piece was attached to the glass plate as the adherend by reciprocating a 2 kg roll once so as to cover the printed frame.
Next, autoclaving was performed for 30 minutes at a pressure of 0.5 MPa in an atmosphere at a temperature of 50 ° C. and left in an atmosphere at a temperature of 65 ° C. and a humidity of 95% RH for 24 hours, and then the inner part of the printed frame was visually observed. Observed and evaluated against the following criteria. The obtained results are shown in Table 1.
◎: Bubbles are not observed ○: Bubbles are observed on one side among four sides constituting the frame Δ: Bubbles are observed on two sides among four sides constituting the frame x: Four sides constituting the frame Inside, bubbles are observed on more than 3 sides

[Example 2 and Comparative Examples 1 to 3]
In Example 2 and Comparative Examples 1 to 3, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the blending ratio of the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A) was changed as shown in Table 1. Manufactured and evaluated the adhesive sheet similarly to Example 1. The obtained results are shown in Table 1.

[Examples 3 to 8]
In Examples 3 to 8, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the blending amounts of isostearyl acrylate and lauryl acrylate as the non-hydrophilic (meth) acrylate monomer as component (B) are shown in Table 2. A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1 except that it was changed to. The obtained results are shown in Table 2.

[Comparative Examples 4 to 9]
In Comparative Examples 4 to 9, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the type and blending amount of the non-hydrophilic (meth) acrylate monomer as the component (B) were changed as shown in Table 3, A pressure-sensitive adhesive sheet was produced and evaluated in the same manner as in Example 1. The obtained results are shown in Table 3.

[Examples 9 to 10 and Comparative Examples 10 to 12]
In Examples 9 to 10 and Comparative Examples 10 to 11, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the blending amount of the hydrogenated terpene resin as the component (C) was changed as shown in Table 4, and Comparative Example No. 12, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a hydrogenated rosin resin (softening point: 100 ° C.) was used as the component (C ′) instead of the hydrogenated terpene resin as the component (C). ,evaluated. Table 4 shows the obtained results.

[Examples 11 to 12 and Comparative Examples 13 to 14]
In Examples 11 to 12 and Comparative Examples 13 to 14, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the amount of 4-hydroxybutyl acrylate as component (D) was changed as shown in Table 5 Manufactured and evaluated the adhesive sheet similarly to Example 1. The results obtained are shown in Table 5.

[Examples 13 to 14 and Comparative Examples 15 to 16]
In Examples 13 to 14 and Comparative Examples 15 to 16, when preparing the ultraviolet curable pressure-sensitive adhesive composition, the blending amount of N, N-diethylacrylamide as the component (E) was changed as shown in Table 6. Otherwise, an adhesive sheet was produced and evaluated in the same manner as in Example 1. The results obtained are shown in Table 6.

[Example 15 and Comparative Examples 17-18]
In Example 15 and Comparative Examples 17 to 18, when preparing the ultraviolet curable pressure-sensitive adhesive composition, it was carried out except that the blending amount of the photopolymerization initiator as the component (F) was changed as shown in Table 7. An adhesive sheet was formed and evaluated in the same manner as in Example 1. The results obtained are shown in Table 7.

According to the ultraviolet curable pressure-sensitive adhesive composition or the like of the present invention, a predetermined non-hydrophilic (meth) acrylate monomer and a hydrogenated terpene resin in a predetermined blending amount with respect to the hydrogenated polybutadiene skeleton urethane acrylate oligomer. Thus, the compatibility between the components can be effectively improved.
As a result, it has become possible to stably obtain a pressure-sensitive adhesive having excellent curability and excellent adhesive properties, transparency, and step following ability.
Therefore, the ultraviolet curable pressure-sensitive adhesive composition of the present invention and the pressure-sensitive adhesive sheet using the same are expected to contribute significantly to improving the quality of liquid crystal touch panels and the like.

Claims (10)

An ultraviolet curable pressure-sensitive adhesive comprising a hydrogenated polybutadiene skeleton urethane acrylate oligomer as component (A), a non-hydrophilic (meth) acrylate monomer as component (B), and a hydrogenated terpene resin as component (C). A composition comprising:
The component (B) contains isostearyl (meth) acrylate and lauryl (meth) acrylate, and the blending amount of the component (B) is 95 to 205 parts by weight with respect to 100 parts by weight of the component (A). A value within the range, and
The ultraviolet curable pressure-sensitive adhesive composition, wherein the blending amount of the component (C) is set to a value in the range of 45 to 95 parts by weight with respect to 100 parts by weight of the component (A).   The blending amount of the isostearyl (meth) acrylate is set to a value within the range of 20 to 65% by weight with respect to the total amount (100% by weight) of the component (B), and the lauryl (meth) acrylate 2. The ultraviolet curable pressure-sensitive adhesive composition according to claim 1, wherein the blending amount is a value within a range of 20 to 70 wt% with respect to the total amount (100 wt%) of the component (B). object.   The component (B) further contains isodecyl (meth) acrylate, and the blending amount of the isodecyl (meth) acrylate is 10 to 30% by weight with respect to the total amount (100% by weight) of the component (B). The ultraviolet curable pressure-sensitive adhesive composition according to claim 1 or 2, wherein the value is within a range.   The weight average molecular weight of the hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A) is set to a value within the range of 3,000 to 100,000. UV curable adhesive composition.   The ultraviolet curable adhesive according to any one of claims 1 to 4, wherein the hydrogenated terpene resin as the component (C) has a weight average molecular weight in a range of 500 to 3,000. Agent composition.   The hydrogenated terpene resin as the component (C) is a completely hydrogenated terpene resin having a softening point in the range of 80 to 180 ° C. The ultraviolet curable adhesive composition of description.   The component (D) further contains a hydrophilic (meth) acrylate monomer, and the blending amount of the component (D) is within a range of 15 to 35 parts by weight with respect to 100 parts by weight of the component (A). The ultraviolet curable pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein   The component (E) further includes an acrylamide compound, and the amount of the component (E) is set to a value within the range of 3 to 12 parts by weight with respect to 100 parts by weight of the component (A). The ultraviolet curable pressure-sensitive adhesive composition according to any one of claims 1 to 7.   (F) As a component, it further contains a photopolymerization initiator, and the blending amount of the component (F) is set to a value within the range of 3 to 8 parts by weight with respect to 100 parts by weight of the component (A). The ultraviolet curable pressure-sensitive adhesive composition according to any one of claims 1 to 8. A pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer formed on the surface of the base material,
The pressure-sensitive adhesive layer comprises a hydrogenated polybutadiene skeleton urethane acrylate oligomer as the component (A), a non-hydrophilic (meth) acrylate monomer as the component (B), and a hydrogenated terpene resin as the component (C). The ultraviolet curable pressure-sensitive adhesive composition contains the component (B) containing isostearyl (meth) acrylate and lauryl (meth) acrylate, and the blending amount of the component (B) is the component (A) 100. The value is within the range of 95 to 205 parts by weight with respect to parts by weight, and the blending amount of the component (C) is within the range of 45 to 95 parts by weight with respect to 100 parts by weight of the component (A). A pressure-sensitive adhesive sheet obtained by curing an ultraviolet curable pressure-sensitive adhesive composition having a value of

Images