KR20160009126A - Adhesive composition for optical use and adhesive film - Google Patents

Abstract

The present invention provides an optical adhesive composition comprising: an isobutylene-based resin; polyisobutylene oligomer having number-average molecular weight of about 1,000 or less; an acrylic acid ester-based photocurable monomer; and an adhesion enhancer, and an adhesive film including an adhesive layer including a cured product thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a pressure-sensitive adhesive composition for optical use,

And a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition for optical use and a cured product thereof.

Touch materials, including packaged electronic devices or transparent conductive films, require excellent touch sensitivity for excellent operation. Further, in recent years, much attention has been focused on the development of pressure-sensitive adhesive compositions for improving the durability and optical characteristics of devices such as OLED or touch screen panels.

Generally, a pressure-sensitive adhesive used for an OLED or a touch screen panel should have optical properties such as transparency and visibility. For this purpose, a pressure sensitive adhesive containing an acrylic resin as a base resin has been generally used, but it has to be supplemented in terms of the improvement of touch sensitivity, and at the same time, studies for securing appropriate modulus and optical properties are actively conducted. to be.

One embodiment of the present invention provides a pressure-sensitive adhesive composition for optical applications capable of realizing an appropriate modulus and touch sensitivity while having excellent optical properties.

Another embodiment of the present invention provides an adhesive film having physical properties suitable for use in an OLED or a touch screen panel including the above optical adhesive composition.

In one embodiment of the present invention, an isobutylene-based resin; A polyisobutylene oligomer having a number average molecular weight of about 1000 or less; Acrylate ester photo-curable monomers; And a pressure-sensitive adhesive enhancer.

The number average molecular weight of the polyisobutylene oligomer may be greater than or equal to about 400 and less than about 800.

The composition may include about 5 to about 30 parts by weight of the polyisobutylene oligomer relative to 100 parts by weight of the isobutylene resin.

The composition may include about 10 to about 50 parts by weight of the photocurable monomer and about 10 to about 70 parts by weight of the adhesion promoter, based on 100 parts by weight of the isobutylene resin.

The isobutylene resin may include at least one selected from the group consisting of polyisobutylene, butyl rubber, and combinations thereof.

The isobutylene resin may have a weight average molecular weight of about 500,000 to about 1,500,000.

The acrylic ester-based photocurable monomer may be selected from the group consisting of dicyclopentadiene (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl And may include at least one selected.

The adhesion promoter may have a refractive index of from about 1.50 to about 1.60.

The adhesion promoter may include at least one selected from the group consisting of hydrogenated dicyclopentadiene compounds, hydrogenated terpene compounds, hydrogenated rosin compounds, hydrogenated aromatic compounds, and combinations thereof.

The tackifier may have a softening point of from about 80 < 0 > C to about 150 < 0 > C.

The refractive index difference between the isobutylene resin and the adhesion promoter may be about 0.02 or less.

The cured product of the optical pressure-sensitive adhesive composition for optical use may have a dielectric constant of about 2.00 or less at a 100 ㎑ thickness of 50 탆 in thickness.

The cured product of the optical pressure-sensitive adhesive composition may have a modulus of about 0.25 MPa or less at 20 캜 to 30 캜.

The cured product of the optical pressure-sensitive adhesive composition for optical use may have a light transmittance of about 85% or more.

The cured product of the optical pressure-sensitive adhesive composition may have a haze of about 1.0% or less.

The optical pressure-sensitive adhesive composition may have a color difference b * of about 0 to about 1.

In another embodiment of the present invention, there is provided an adhesive film comprising a pressure-sensitive adhesive layer comprising a cured product of the optical pressure-sensitive adhesive composition.

The adhesive film may include a release film layer laminated on one side or both sides of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer may have a dielectric constant of about 2.00 or less at 100 kHz with a thickness of 50 m.

The pressure-sensitive adhesive layer may have a modulus of about 0.25 MPa or less.

The optical pressure-sensitive adhesive composition for optical use can realize excellent optical properties, and at the same time can achieve appropriate modulus and excellent touch sensitivity.

The adhesive film comprising the optical pressure-sensitive adhesive composition can be applied to an OLED or a touch screen panel, thereby realizing excellent optical characteristics and touch sensitivity.

1 schematically shows a cross section of an adhesive film according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which the invention pertains. Only.

In one embodiment of the present invention, an isobutylene-based resin; A polyisobutylene oligomer having a number average molecular weight of about 1000 or less; Acrylate ester photo-curable monomers; And a pressure-sensitive adhesive enhancer.

The optical pressure-sensitive adhesive composition for optical use may be used for an OLED or a touch screen panel. In this case, touch sensitivity is one of the important characteristics. At the same time, an appropriate modulus must be implemented. To this end, the optical pressure-sensitive adhesive composition for optical use contains a polyisobutylene oligomer together with an isobutylene-based resin to control the modulus and the dielectric constant, thereby realizing excellent touch sensitivity and adhesion.

The optical pressure-sensitive adhesive composition for optical use includes an isobutylene-based resin, which realizes a low dielectric constant property, and can realize excellent touch sensitivity through the optical pressure-sensitive adhesive composition for optical use. However, the isobutylene-based resin increases the modulus of the pressure-sensitive adhesive composition, thereby deteriorating the pressure-sensitive adhesive performance. This is because when the pressure-sensitive adhesive composition for optical use is applied to an OLED, a touch screen panel, or the like, it lowers the step absorption performance and the wetting performance It can cause problems. Accordingly, the optical pressure-sensitive adhesive composition for optical use may comprise a separate polyisobutylene oligomer having a number average molecular weight of about 1000 or less, thereby controlling the modulus.

The polyisobutylene oligomer may have a number average molecular weight (Mn) of about 1000 or less. When the number average molecular weight (Mn) of the polyisobutylene oligomer is more than about 1000, the compatibility with the isobutylene resin is lowered, the haze is increased, and the visibility is lowered. There is a fear that it will not be able to do.

For example, the polyisobutylene oligomer may have a number average molecular weight (Mn) of about 400 or more and less than about 800, and by satisfying the above range, excellent compatibility, visibility, and suitable modulus can be realized, It is possible to prevent the problem of dewetting and bubbling at the interface when coating the complex, and realize an excellent low dielectric constant property.

When the number average molecular weight of the polyisobutylene oligomer satisfies the above range, a suitable modulus, low dielectric constant, and excellent optical characteristics can be secured at the same time.

Specifically, the optical pressure-sensitive adhesive composition may contain about 5 to about 30 parts by weight of the polyisobutylene oligomer relative to 100 parts by weight of the isobutylene-based resin. If the content of the polyisobutylene oligomer is less than about 5 parts by weight, the content of the isobutylene resin may be relatively high, resulting in an excessively increased modulus of the pressure-sensitive adhesive composition, resulting in a deterioration in the step difference absorption performance of the pressure-sensitive adhesive. Also, when the content of the polyisobutylene oligomer exceeds about 30 parts by weight, the curing density of the pressure-sensitive adhesive components may be weakened, and reliability of the pressure-sensitive adhesive may deteriorate in a high temperature and high humidity environment when the pressure-sensitive adhesive is applied to the apparatus.

Also, the optical pressure-sensitive adhesive composition for optical use may contain about 10 to about 50 parts by weight of the photocurable monomer relative to 100 parts by weight of the isobutylene-based resin. When the photo-curable monomer is contained in an amount of less than about 10 parts by weight, the pressure-sensitive adhesive composition can not sufficiently cure, resulting in an excessively low curing degree, and may be vulnerable to durability in a high temperature and high humidity environment. Also, when the photo-curable monomer is contained in an amount exceeding about 50 parts by weight, miscibility with the isobutylene resin and the tackifier may be lowered, resulting in a higher haze and a harder tackifier .

In addition, the optical pressure-sensitive adhesive composition may contain about 10 to about 70 parts by weight of the pressure-sensitive adhesive agent per 100 parts by weight of the isobutylene-based resin. When the tackifier is contained in an amount of less than about 10 parts by weight, peeling force of the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition may be deteriorated. In addition, when the tackifier is contained in an amount of more than about 70 parts by weight, the glass transition temperature tends to be high and the tack property may deteriorate, and the peeling force may be lowered. The pressure- Hard).

The optical pressure-sensitive adhesive composition for optical use includes an isobutylene-based resin, and the isobutylene-based resin has a low dielectric constant to realize excellent touch sensitivity. Specifically, the isobutylene resin may include at least one selected from the group consisting of polyisobutylene, butyl rubber, and combinations thereof. The polyisobutylene is a polymer obtained by polymerizing an isobutylene monomer alone, and the butyl rubber is an isobutylene-isoprene copolymer, most of which is a copolymer containing isobutylene and a small amount of isoprene.

The butyl rubber may include about 1 mol% to about 5 mol% of isoprene in 100 mol% of the total monomers constituting the butyl rubber. When the content of isoprene is less than about 1 mol%, the double bonds in the butyl rubber are inadequate to lower the durability of the pressure-sensitive adhesive composition at the time of curing. When the content of the isoprene is more than about 5 mol% There is a fear that the moisture permeation preventing performance of the pressure-sensitive adhesive is lowered.

The isobutylene-based resin may have a weight average molecular weight (Mw) of about 500,000 to about 1,500,000, specifically about 500,000 to about 1,000,000, and more specifically about 500,000 to about 800,000. When the weight average molecular weight (Mw) of the isobutylene resin is less than about 500,000, the physical entanglement site may be insufficient to reduce durability and dewetting may occur during coating. When the weight average molecular weight of the isobutylene resin exceeds about 1,500,000, the viscosity of the pressure-sensitive adhesive composition increases sharply, which is disadvantageous in view of process conditions and compatibility with the polyisobutylene oligomer and the pressure-sensitive adhesion promoter, The roughness of the film during coating increases, which may result in loss of coating uniformity.

The optical pressure-sensitive adhesive composition for optical use may contain an acrylic ester-based photopolymerizable monomer so as to be cured by ultraviolet rays. Since the isobutylene resin is hardly cured by light irradiation itself, it can be cured to be mounted in an OLED or a touch screen panel by incorporating a certain amount of photo-curable monomer. Since the optical pressure-sensitive adhesive composition for optical use contains acrylic ester-based photo-curable monomer, excellent compatibility with the isobutylene-based resin and the pressure-sensitive adhesive can be ensured, and advantageous effects can be achieved in terms of securing optical properties such as peeling force and visibility .

Specifically, the acrylic ester-based photo-curable monomer may be prepared by copolymerizing dicyclopentadiene (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl And the like. The (meth) acrylate includes both acrylate and methacrylate. For example, the acrylate ester photo-curable monomer may include dicyclopentadiene (meth) acrylate or isobornyl (meth) acrylate. In this case, especially, the refractive index increasing effect is excellent due to the structural characteristics, A more advantageous effect can be realized in terms of compatibility with the isobutylene resin and the tackifier.

Since the isobutylene resin has low moisture permeability, it is difficult to secure a peel force and adhesion force for itself to be used as an optical adhesive. Accordingly, the optical pressure-sensitive adhesive composition for optical use may contain a tackifier in order to secure a peel force and an adhesive force.

Specifically, the tackifier may have a refractive index of from about 1.50 to about 1.60, and more specifically from about 1.50 to about 1.55, and more specifically from about 1.50 to about 1.52. The optical pressure-sensitive adhesive composition for optical use has excellent compatibility with the isobutylene-based resin by including a pressure-sensitive adhesive having a refractive index within the above-mentioned range, and can exhibit excellent transparency and visibility when used in an OLED or a touch screen panel.

The adhesion promoter may include a hydrogenated dicyclopentadiene compound, a hydrogenated terpene compound, a hydrogenated rosin compound, or a hydrogenated aromatic compound. Since the adhesion promoter contains a hydrogenated structure, it can be advantageous in securing transparency and less adversely affected by light energy at the time of photo-curing, thereby securing excellent adhesion and peeling force.

For example, the adhesion-promoting agent may include a hydrogenated dicyclopentadiene-based compound or a hydrogenated rosin-based compound, and in this case, particularly, an effect that tack performance is imparted and optical properties such as light transmittance and haze are improved Can be obtained.

The hydrogenated tackifier may be partially hydrogenated or fully hydrogenated. Specifically, the hydrogenated tackifier can have a hydrogenation rate of about 60% or more, for example, 100%. If the hydrogenation rate is less than about 60%, the pressure-sensitive adhesive layer containing a large amount of double bonds in the molecule may decrease the visibility and transparency of the pressure-sensitive adhesive composition, and the tendency of the double bonds to absorb the light energy becomes large. There is a problem in that when the light energy is irradiated for curing, it is absorbed and, as a result, the tackiness and the peeling force become uneven.

Further, the tackifier may have a softening point of about 80 캜 to about 150 캜, specifically about 80 캜 to about 130 캜, and more specifically about 100 캜 to about 120 캜. The softening point generally refers to the temperature at which, when heat is applied to a material, it begins to undergo strain or softening by heat. When the softening point of the pressure-sensitive adhesive is less than about 80 캜, the pressure-sensitive adhesive may soften at a relatively low temperature, and the reliability of the pressure-sensitive adhesive containing the pressure-sensitive adhesive may deteriorate. When the pressure- There is a problem that it is difficult to distribute and store at a high temperature. When the temperature exceeds about 150 ° C, there is a problem that it is difficult to realize the effect of improving the tackiness of the pressure-sensitive adhesive at room temperature, and there is a problem that the pressure- .

The optical pressure-sensitive adhesive composition includes an isobutylene-based resin and an adhesion promoter, and the refractive index difference between the isobutylene resin and the adhesion promoter may be 0.02 or less. When the refractive index difference is 0.02 or less, the isobutylene resin and the pressure-sensitive adhesion promoter can ensure excellent compatibility, and the optical pressure-sensitive adhesive composition including the same can easily realize excellent visibility and transparency. The smaller the refractive index difference is, the better the effect of improving the compatibility, the visibility and the transparency is, and when the refractive index is the same, the effect can be maximized.

The optical pressure-sensitive adhesive composition may further include a photoinitiator. When the optical pressure-sensitive adhesive composition contains a photoinitiator, the photo-curable monomer can be cured upon light irradiation, thereby forming a cured product from the pressure-sensitive adhesive composition. When the optical pressure-sensitive adhesive composition includes a photoinitiator, the photoinitiator may be included in an amount of about 0.1 to about 5 parts by weight based on 100 parts by weight of the isobutylene resin. By incorporating the photoinitiator in the above range, the photo-curing efficiency of the optical pressure-sensitive adhesive composition can be maximized, and more advantageous effects can be achieved in terms of production cost and securing optical characteristics such as color difference b *.

The photoinitiator may be selected from the group consisting of benzoin methyl ether, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide,?,? - methoxy -? - Phenanone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-dimethoxy-2- 2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl] -1-methyl- -1-butanone, and combinations thereof.

The optical pressure-sensitive adhesive composition for optical use may be cured to form a cured product. For example, the cured product may be used as an adhesive layer to be mounted in an OLED or a touch screen panel to impart excellent touch sensitivity, tack-improving effect, and optical characteristics.

The cured product of the optical pressure-sensitive adhesive composition may have a dielectric constant of about 2.00 or less, specifically about 1.90 or less, and more specifically about 1.80 or less at 100 kHz of a thickness of 50 m. When the dielectric constant exceeds the above range, there is a fear that touch sensitivity is lowered when the cured product is applied to a touch screen panel or the like. The optical pressure-sensitive adhesive composition includes the isobutylene resin and the polyisobutylene oligomer together, and the cured product obtained by curing the cured product exhibits a modulus suitable for the range of the above-mentioned permittivity, thereby obtaining excellent touch sensitivity and step difference absorption performance .

The cured product of the optical pressure-sensitive adhesive composition may have a modulus of about 0.25 MPa or less, specifically about 0.20 MPa or less, more specifically about 0.16 MPa or less at a temperature of about 20 캜 to about 30 캜. The modulus is defined as the ratio of stress to strain (Stress / Strain) and is a measure of the stiffness or softness of the adhesive. That is, the higher the modulus, the harder the pressure-sensitive adhesive. The optical pressure-sensitive adhesive composition includes the isobutylene-based resin and the polyisobutylene oligomer together so that the cured product obtained by curing the cured product can realize a modulus in the above range together with a low dielectric constant property. If the modulus of the cured product is higher than the above range at a temperature of about 20 ° C to about 30 ° C, the step difference absorption performance of the pressure sensitive adhesive is lowered, thereby deteriorating the high temperature reliability and reducing the durability of the device .

The cured product of the optical pressure-sensitive adhesive composition may have a peel force against glass of about 1000 g / in or more, specifically about 1500 g / in or more. When the peeling force is less than about 1000 g / in, there is a problem that the adhesive is detached from an adherend, and when used in an OLED or a touch screen panel, moisture resistance and adhesiveness can not be secured at the same time. That is, when the cured product of the optical pressure-sensitive adhesive composition for optical use maintains the peeling force within the above-mentioned range, excellent adhesive property and moisture resistance can be easily achieved at the same time when used in an OLED or a touch screen panel.

The cured product of the optical pressure-sensitive adhesive composition may have a light transmittance of about 85% or more, specifically about 90% or more, and more specifically about 93% or more. The optical pressure-sensitive adhesive composition for optical use together with the isobutylene-based resin, the polyisobutylene oligomer, and the pressure-sensitive adhesive improves a light transmittance of about 85% or more in a cured product obtained by curing the adhesive. When the light transmittance is less than about 85%, the cured product hardly realizes excellent transparency, and, for example, when used in an OLED or a touch screen panel, there is a fear that excellent optical characteristics may not be realized.

The cured product of the optical pressure-sensitive adhesive composition may have a haze of about 1.0% or less, specifically about 0.6% or less, more specifically about 0.3% or less. If the haze exceeds about 1.0%, the transparency of the cured product may be deteriorated, and when the cured product is applied to a touch screen panel or the like, transparency required may not be secured. By maintaining the haze of the cured product of the optical pressure-sensitive adhesive composition in the above range, excellent visibility can be ensured when used in a touch screen panel.

When the white light (D65) is irradiated to the cured product by the colorimetric system established by the International Lighting Commission (CIE), the color difference due to the transmitted light is expressed by the CIE 10 ° standard observer (CIE 1964) A *, b * defined as the distance between the two colors in the color space is consistent with the degree of color difference seen by a person. At this time, a white light source (D65) is added to the cured material in a wavelength region of about 380 nm to about 780 nm, where L * represents brightness, a * represents Red-Green, and b * represents a value between Yellow- When the light is irradiated, the values derived from the transmitted light can be represented by the color difference a * and the color difference b *.

The cured product of the optical pressure-sensitive adhesive composition may have a color difference b * of about 0 to about 1, specifically about 0 to about 0.5, and more specifically about 0 to about 0.2.

The color difference b * affects the high temperature reliability of the pressure sensitive adhesive. The cured product of the pressure sensitive adhesive composition for optical use can realize the color difference b * in the above range by including the isobutylene based resin and the pressure sensitive adhesive, By displaying the color difference b * in the above range, it is possible to realize an effect of ensuring excellent visibility even at a high temperature.

On the other hand, the cured product of the optical pressure-sensitive adhesive composition may have a color difference a * of about -0.1 to about 0. When the color difference a * of the cured product satisfies the above range, the absolute values of the color differences a * and b * are all close to zero. Thus, moire phenomenon can be prevented and excellent visibility can be ensured when using the touch screen panel.

The optical pressure-sensitive adhesive composition for optical use contains an isobutylene-based resin, and its cured product has a water vapor transmission rate (WVTR) of about 10 g / m < 2 > And specifically about 6 g / m 2 24 hr or less. When the moisture permeability of the cured product is more than about 10 g / m 2 .24 hr, the durability of the device including the cured product may be lowered. For example, when the cured product is used in a touch screen panel, So that the function as the touch sensor may be lost. That is, by maintaining the moisture permeability of the cured product of the optical pressure-sensitive adhesive composition in the above-described range, moisture resistance and durability of the device including the same can be improved.

Another embodiment of the present invention provides an adhesive film comprising a pressure-sensitive adhesive layer comprising a cured product of the optical pressure-sensitive adhesive composition.

The adhesive film may be used in an optical product such as an OLED or a touch screen panel, and a pressure-sensitive adhesive layer containing a cured product of the optical pressure-sensitive adhesive composition is placed inside the OLED or the touch screen panel to serve as sealing or sealing Can be performed.

Specifically, the adhesive film may include a release film layer laminated on one side or both sides of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer. The release film layer may be laminated on one side or both sides of the pressure-sensitive adhesive layer as a layer to be peeled off when the pressure-sensitive adhesive film is finally used, whereby the pressure-sensitive adhesive layer can be finally attached to the adherend have.

1 schematically shows a cross section of an adhesive film 100 according to an embodiment of the present invention. Referring to FIG. 1, the adhesive film 100 may include a releasing film layer 110 laminated on both sides of the pressure-sensitive adhesive layer 120 and the pressure-sensitive adhesive layer 120. The adhesive film 100 may be disposed such that the adhesive layer 110 laminated on both sides of the adhesive layer 120 is peeled off and both sides of the adhesive layer 120 are attached to the adherend.

The pressure-sensitive adhesive layer may include a cured product of the optical pressure-sensitive adhesive composition, and may have properties of dielectric constant, modulus, light transmittance, peeling force, haze, and color difference of the cured product. The above dielectric constant, modulus, light transmittance, peeling force to glass, haze and color difference are as described above.

The pressure-sensitive adhesive layer can be used, for example, in a touch screen panel. Specifically, the pressure-sensitive adhesive layer can be used as an optical clear adhesive (OCA) layer on a transparent conductive film including a glass cover window and ITO have. Since the pressure-sensitive adhesive layer contains a cured product of the optical pressure-sensitive adhesive composition, excellent optical properties and touch sensitivity for use as the optical transparent pressure-sensitive adhesive layer can be secured at the same time, and excellent step- have.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

< Example  And Comparative Example >

Example  One

20 parts by weight of a polyisobutylene oligomer having a number average molecular weight of 200 and 20 parts by weight of a dicyclopentadiene-based adhesion promoter having a hydrogenation rate of 100% and a refractive index of 1.52, based on 100 parts by weight of butyl rubber (BASF, Oppanol B 80) And 20 parts by weight of a photocurable monomer of dicyclopentadiene diacrylate (Eternal, Taiwan) were mixed to prepare an optical pressure-sensitive adhesive composition. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Example  2

20 parts by weight of a polyisobutylene oligomer having a number average molecular weight of 450, 20 parts by weight of a dicyclopentadiene-based adhesion promoter having a hydrogenation rate of 100% and a refractive index of 1.52 based on 100 parts by weight of butyl rubber (BASF, Oppanol B 80) And 20 parts by weight of a photocurable monomer of dicyclopentadiene diacrylate (Eternal, Taiwan) were mixed to prepare an optical pressure-sensitive adhesive composition. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Example  3

20 parts by weight of a polyisobutylene oligomer having a number average molecular weight of 450, 100 parts by weight of a polyisobutylene resin (BASF, Oppanol B 80) 30 parts by weight of a dicyclopentadiene-based adhesion promoter having a refractive index of 1.52 and 20 parts by weight of a photocurable monomer of dicyclopentadiene diacrylate (Eternal, Taiwan) were mixed to prepare an optical pressure-sensitive adhesive composition. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Example  4

20 parts by weight of a polyisobutylene oligomer having a number average molecular weight of 450, 20 parts by weight of a dicyclopentadiene-based adhesive resin having a hydrogenation degree of 20% and a refractive index of 1.52, and 100 parts by weight of a polyisobutylene resin (BASF, Oppanol B 80) 30 parts by weight of an enhancer and 20 parts by weight of a photocurable monomer of dicyclopentadiene diacrylate (Eternal, Taiwan) were mixed to prepare an optical pressure-sensitive adhesive composition. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Example  5

And 20 parts by weight of a polyisobutylene oligomer having a number-average molecular weight of 800, to prepare a pressure-sensitive adhesive layer.

Comparative Example  One

Sensitive adhesive composition for optical use was prepared by mixing 20 parts by weight of a dicyclopentadiene-based adhesion promoter having a hydrogenation rate of 100% and a refractive index of 1.52 with respect to 100 parts by weight of an acrylic resin. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Comparative Example  2

30 parts by weight of a linear petroleum type adhesion promoter having a hydrogenation rate of 100% and a refractive index of 1.49, and 30 parts by weight of dicyclopentadiene diacrylate (manufactured by Taiwan Eternal Co., Ltd.) based on 100 parts by weight of a polyisobutylene resin (BASF, Oppanol B 80) G) 20 parts by weight of a photopolymerizable monomer were mixed to prepare an optical pressure-sensitive adhesive composition. 1 part by weight of a photoinitiator (BASF, Irgacure 184) was mixed with the optical pressure-sensitive adhesive composition for optical use, followed by photo-curing by irradiation with light energy of 2,000 mJ / cm 2 UV-A to prepare a pressure-sensitive adhesive layer.

Comparative Example  3

A pressure-sensitive adhesive layer was prepared in the same manner as in Example 1, except that the optical pressure-sensitive adhesive composition for optical use did not contain the polyisobutylene oligomer.

Comparative Example  4

A pressure-sensitive adhesive layer was prepared in the same manner as in Example 1, except that the pressure-sensitive adhesive composition for optical use did not contain the pressure-sensitive adhesive and the polyisobutylene oligomer.

Comparative Example  5

And 20 parts by weight of a polyisobutylene oligomer having a number average molecular weight of 1,200 was prepared in the same manner as in Example 3.

division Suzy Adhesion enhancer Photocurable monomer Oligomer rescue Hydrogenation rate Refractive index Example 1 Butyl rubber Dicyclopentadiene series 100% 1.52 DCPDA PIB
Mn 200 Example 2 Butyl rubber Dicyclopentadiene series 100% 1.52 DCPDA PIB
Mn 450 Example 3 Polyisobutylene Dicyclopentadiene series 100% 1.52 DCPDA PIB
Mn 450 Example 4 Polyisobutylene Dicyclopentadiene series 20% 1.52 DCPDA PIB
Mn 450 Example 5 Butyl rubber Dicyclopentadiene series 100% 1.52 DCPDA PIB
Mn 800 Comparative Example 1 Acrylic resin Dicyclopentadiene series 100% 1.52 - - Comparative Example 2 Polyisobutylene Linear-structured petroleum 100% 1.49 DCPDA - Comparative Example 3 Butyl rubber Dicyclopentadiene series 100% 1.52 DCPDA - Comparative Example 4 Butyl rubber - DCPDA - Comparative Example 5 Polyisobutylene Dicyclopentadiene series 100% 1.52 DCPDA PIB
Mn 1200

<Evaluation>

The pressure-sensitive adhesive layers of Examples 1 to 5 and Comparative Examples 1 to 5 were cut to have a thickness of 50 탆, and the following physical properties were measured, and the results are shown in Table 2 below.

Experimental Example  1: Measurement of dielectric constant

The capacitance (Cp) of the pressure-sensitive adhesive layer was measured using a measuring device (Agilent E4980A), and the dielectric constant was calculated by the following general formula (1) using the measured capacitance (Cp).

[Formula 1]

ε = ε ₀ ε _r = Cp x t / A

In the formula 1, and ε is the dielectric constant, ε ₀ is the permittivity in vacuum, ε _r is the relative permittivity of the adhesive layer, Cp is the measured capacitance values, t is the thickness of the pressure-sensitive adhesive layer, A Represents an area of the pressure-sensitive adhesive layer sample contacting the electrode when the capacitance (Cp) is measured.

Experimental Example  2: Modulous  Measure

The storage modulus of the modulus of the pressure-sensitive adhesive layer was measured using a measuring device (ARES G2) at 25 ° C.

Experimental Example  3: Measurement of optical properties

One) Measurement of light transmittance

After attaching the pressure-sensitive adhesive layer to a transparent glass substrate, the light transmittance was measured using a UV-Vis spectrometer at 20 ° C to 30 ° C at room temperature.

2) Measurement of haze

After attaching the pressure-sensitive adhesive layer to a transparent glass substrate, the haze was measured with a haze meter (BYK company) at 20 ° C to 30 ° C at room temperature.

3) Measurement of color difference

The pressure-sensitive adhesive layer was adhered to a transparent glass substrate, and color difference was measured using CM-5 (Konica Minolta, color difference meter) at 20 ° C to 30 ° C at room temperature.

division permittivity Modulus
(MPa) Optical characteristic Light transmittance (%) Haze (%) Color difference b * Example 1 1.82 0.14 92.8 0.21 0.21 Example 2 1.78 0.15 93.2 0.18 0.14 Example 3 1.76 0.16 93.1 0.21 0.13 Example 4 1.80 0.16 92.0 0.55 0.92 Example 5 1.81 0.19 92.8 0.63 0.15 Comparative Example 1 2.91 0.09 92.1 0.80 0.20 Comparative Example 2 2.04 0.27 92.1 1.43 0.45 Comparative Example 3 1.94 0.27 92.0 0.20 0.21 Comparative Example 4 2.98 0.35 92.1 0.18 0.31 Comparative Example 5 1.94 0.38 93.1 0.54 0.18

As shown in Table 1, Examples 1 to 5 were formed from an optical pressure-sensitive adhesive composition containing an isobutylene-based resin and a polyisobutylene oligomer having a number average molecular weight of 1000 or less, and exhibited a low dielectric constant of 2.00 or less, The modulus of 0.25 MPa or less is exhibited. Unlike Comparative Examples 2 to 4, which include isobutylene-based resins but do not include polyisobutylene oligomer, low-permittivity characteristics and appropriate modulus characteristics are realized at the same time, It can be confirmed that the embodiments 1 to 5 have an effect of realizing excellent touch sensitivity and adhesive performance at the same time.

Examples 2 to 4 were formed from an optical pressure-sensitive adhesive composition containing a polyisobutylene oligomer having a number-average molecular weight of about 400 or more and less than about 800 together with an isobutylene-based resin and exhibited a low dielectric constant of 1.80 or less, The modulus of 0.16 MPa or less is exhibited, and it can be seen that both excellent touch sensitivity and adhesive performance are realized at the same time.

In Examples 2 to 3, the pressure-sensitive adhesive was hydrogenated at 100% with an isobutylene-based resin. In contrast to Example 4 in which the hydrogenation rate was only 20%, the light transmittance, haze and color difference It can be understood that excellent optical characteristics are realized.

The comparative example 5 contains a polyisobutylene oligomer having a number average molecular weight of more than 1000, specifically a number average molecular weight of 1200, which is higher than that of Examples 1 to 5 in both dielectric constant and modulus. As a result, in Examples 1 to 5, the polyisobutylene oligomer having a number average molecular weight of 1000 or less was included, thereby ensuring low dielectric constant characteristics and appropriate modulus at the same time, and superior touch sensitivity, . &Lt; / RTI &gt;

 Comparative Example 1 includes an acrylic resin rather than an isobutylene resin and exhibited a lower modulus than those of Examples 1 to 5. However, the dielectric constant was significantly higher than that of Examples 1 to 5, The sensitivity is inferior. In other words, in the case of Examples 1 to 5, both the isobutylene-based resin and the polyisobutylene oligomer can be simultaneously incorporated to realize an excellent touch sensitivity, and at the same time, an appropriate modulus for realizing excellent adhesion performance can be ensured.

In addition, Comparative Example 4, which does not include both the polyisobutylene oligomer and the adhesion promoter, showed higher permittivity and modulus than Examples 1 to 5. In Examples 1 to 5, polyisobutyl It is understood that the effect of improving the touch sensitivity, the coating property, and the tackiness is more excellent by including both the phenol oligomer and the tackifier.

The comparative example 2 includes the adhesion promoter having a refractive index of 1.49 and has a dielectric constant higher than that of the comparative example 3 including a dicyclopentadiene adhesion promoter having a refractive index of 1.50 to 1.60 and a haze exceeding 1% , The touch sensitivity enhancement effect and the visibility improvement effect are more easily realized through the adhesion promoter having the refractive index of 1.50 to 1.60.

The optical pressure-sensitive adhesive composition for optical use can realize excellent optical characteristics, at the same time, can secure proper modulus and low dielectric constant characteristics, and can realize excellent touch sensitivity, coating property and adhesiveness together with excellent visibility and transparency.

In addition, the adhesive film comprising the optical pressure-sensitive adhesive composition can be applied to an OLED or a touch screen panel, thereby securing excellent optical characteristics, touch sensitivity, coating property and adhesiveness.

100: Adhesive film
110: release film layer
120: pressure-sensitive adhesive layer

Claims (20)

An isobutylene-based resin; A polyisobutylene oligomer having a number average molecular weight of 1000 or less; Acrylate ester photo-curable monomers; And a tackifier
Sensitive adhesive composition for optics.
The method according to claim 1,
Wherein the polyisobutylene oligomer has a number average molecular weight of 400 or more and less than 800
Sensitive adhesive composition for optics.
The method according to claim 1,
Based on 100 parts by weight of the isobutylene-based resin, 5 to 30 parts by weight of the polyisobutylene oligomer
Sensitive adhesive composition for optics.
The method according to claim 1,
10 to 50 parts by weight of the photocurable monomer and 10 to 70 parts by weight of the adhesion promoter, based on 100 parts by weight of the isobutylene resin,
Sensitive adhesive composition for optics.
The method according to claim 1,
Wherein the isobutylene resin comprises at least one member selected from the group consisting of polyisobutylene, butyl rubber, and combinations thereof
Sensitive adhesive composition for optics.
The method according to claim 1,
The isobutylene-based resin has a weight average molecular weight of 500,000 to 1,500,000
Sensitive adhesive composition for optics.
The method according to claim 1,
The acrylic ester-based photocurable monomer may be selected from the group consisting of dicyclopentadiene (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl Comprising one or more selected
Sensitive adhesive composition for optics.
The method according to claim 1,
The adhesion promoter preferably has a refractive index of 1.50 to 1.60
Sensitive adhesive composition for optics.
The method according to claim 1,
Wherein the adhesion promoter comprises at least one selected from the group consisting of a hydrogenated dicyclopentadiene compound, a hydrogenated terpene compound, a hydrogenated rosin compound, a hydrogenated aromatic compound, and combinations thereof
Sensitive adhesive composition for optics.
The method according to claim 1,
The adhesion promoter preferably has a softening point of from 80 캜 to 150 캜
Sensitive adhesive composition for optics.
The method according to claim 1,
The isobutylene-based resin and the adhesion promoter preferably have a refractive index difference of 0.02 or less
Sensitive adhesive composition for optics.
The method according to claim 1,
The cured product of the optical pressure-sensitive adhesive composition for optical use had a dielectric constant of 2.00 or less
Sensitive adhesive composition for optics.
The method according to claim 1,
The cured product of the optical pressure-sensitive adhesive composition for optical use has a modulus of 0.25 MPa or less at 20 캜 to 30 캜
Sensitive adhesive composition for optics.
The method according to claim 1,
The cured product of the optical pressure-sensitive adhesive composition for optical use has a light transmittance of 85%
Sensitive adhesive composition for optics.
The method according to claim 1,
The cured product of the optical pressure-sensitive adhesive composition for optical use has a haze of 1.0% or less
Sensitive adhesive composition for optics.
The method according to claim 1,
The cured product of the optical pressure-sensitive adhesive composition for optical use has a color difference b * of 0 to 1
Sensitive adhesive composition for optics.
A pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive composition for optical use according to any one of claims 1 to 16.
18. The method of claim 17,
Wherein the adhesive film comprises a release film layer laminated on one side or both sides of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer
Adhesive film.
18. The method of claim 17,
The pressure-sensitive adhesive layer had a dielectric constant of 2.00 or less
Adhesive film.
18. The method of claim 17,
The pressure-sensitive adhesive layer preferably has a modulus of 0.25 MPa or less
Adhesive film.

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