KR100606605B1 - Pressure sensitive adhesive composition for optical use - Google Patents

Abstract

The present invention relates to an optically clear optical pressure sensitive adhesive composition comprising a UV absorber. More specifically, the optical material used in the PDP filter including a transparent substrate containing a color correction function that absorbs light in the visible region as a filter material used to correct color balance in the PDP. It relates to a pressure-sensitive adhesive composition for. Optical pressure-sensitive adhesive composition according to the present invention including a UV absorber is characterized in that it comprises a pressure-sensitive adhesive and 0.05 to 5 parts by weight of a UV absorber per 100 parts by weight of the pressure-sensitive adhesive, the transmittance is 90% or more The Haze of the antistatic pressure-sensitive adhesive composition is less than 1%, and the UV property is less than 5% when the UV Visible Spectrometer is measured at 380 nm or less.

Adhesive, UV Absorber, Pressure Sensitive

Description

PRESSURE SENSITIVE ADHESIVE COMPOSITION FOR OPTICAL USE

The present invention relates to an optically clear optical pressure sensitive adhesive composition comprising a UV absorber. More specifically, the optical material used in the PDP filter including a transparent substrate containing a color correction function that absorbs light in the visible region as a filter material used to correct color balance in the PDP. It relates to a pressure-sensitive adhesive composition for.

In general, a plasma display panel (PDP) is composed of a discharge gas such as neon, argon, xenon, etc. encapsulated between transparent electrodes printed on a glass tube, and uses a phenomenon of emitting light by gas discharge between electrodes. Or it is advantageous to form a large screen compared to LCD. However, this PDP generates a lot of electromagnetic waves, ultraviolet rays, and near infrared rays. When light is emitted from red, green, and blue trichromatic phosphors, strong visible light is generated in the range of 580 to 590 nm. The presence of additional equipment is essential.

Accordingly, Japanese Patent Application Laid-Open No. 1983-153904 has proposed a PDP using a method of attaching a filter capable of absorbing light of a specific wavelength to the front surface of the PDP in order to correct the color balance of the display color. As a method for blocking harmful light and correcting PDP screen color using such a filter, Japanese Laid-Open Patent Publication No. 1999-160532 discloses a method of separately forming a resin layer containing a near-infrared absorber for color correction on a substrate. Patent No. 2000-340985 discloses a method for controlling the concentration thereof by including a color correction pigment in a transparent adhesive used for bonding members of a PDP filter. In addition, Japanese Patent Laid-Open No. 2001-343520 uses a method of directly dispersing a pigment for coloring a dye in a resin or an adhesive to be applied for improving mesh transparency.

However, these color correction materials may lose reliability due to external UV waves, and for this reason, there is a need for a material that protects workability and required properties, including a UV absorber inside the pressure-sensitive adhesive. to be.

Since conventional pressure-sensitive adhesives do not have a UV absorbing function, they have a limit in protecting color correction materials such as pigments and dyes from UV rays. In particular, when using a multilayer optical film, such a function is required more.

Typical applications of pressure sensitive adhesives with added UV absorption can be used in optical filters of PDPs. Such a UV absorbent pressure-sensitive adhesive is preferable to have the property that the physical properties are maintained without being destroyed by sunlight or ultraviolet rays. In particular, the composition used in the optical filter is weak in durability and often loses its function when exposed to heat, direct sunlight, moisture, there is a limit to the type of resin for the adhesive, coating method and the like can be used.

In addition, with the explosive growth of the PDP market, requirements for optical properties and durability of the filters used therein are becoming increasingly demanding.

The present invention has been made to solve the above problems, an object of the present invention is to provide an optical pressure-sensitive adhesive composition excellent in transparency and UV absorption function.

It is also an object of the present invention to provide an optical pressure-sensitive adhesive composition that can be produced relatively simple and economical.

Optical pressure-sensitive adhesive composition according to the present invention for achieving the above object is a pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive and a UV absorber for absorbing light in the region of 380nm or less, UV transmittance of 5% or less in the region of 380nm It is characterized by being less than.

In a preferred embodiment, the pressure-sensitive adhesive composition is characterized in that the total Haze is 1% or less, and the pressure-sensitive adhesive composition is characterized in that the total transmittance is 90% or more.

In addition, the optical pressure-sensitive adhesive composition according to the invention is characterized in that it comprises a pressure-sensitive adhesive and 0.05 to 5 parts by weight of a UV absorber per 100 parts by weight of the pressure-sensitive adhesive, the UV absorber is the pressure-sensitive adhesive It is characterized in that 0.05 to 3 parts by weight per 100 parts by weight.

In a preferred embodiment, the pressure-sensitive adhesive is a pressure-sensitive adhesive based on poly (meth) acrylate, the UV absorber is characterized in that the hydroxyphenylbenzotriazole (Hydroxyphenylbenzotriazole) -based UV absorber.

In a further preferred embodiment, the hydroxyphenylbenzotriazole UV absorber is octyl-3 [3-tertiary-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] Propionate (Octyl-3- [3- tert- butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate), another preferred embodiment In the hydroxyphenylbenzotriazole-based UV absorber 2- (2-hydroxy-3-tertiary-butyl-5-methylphenyl) -5-chlorobenzotriazole (2- (2-Hydroxy-3-tert-butyl -5-methylphenyl) -5-chlorobenzotriazole).

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. .

The pressure-sensitive adhesive of the optical pressure-sensitive adhesive composition according to the present invention is, for example, natural rubber, synthetic rubber, styrene block copolymer, polyvinyl ether, poly (meth) acrylate (including acrylate and methacrylate). Pressure-sensitive adhesives, including those based on polyolefins and silicones, and having the following general properties. That is, (1) aggressive and permanent viscosity, (2) adhesion to the substrate at a constant pressure, (3) sufficient ability to remain on the attachment, and (4) adhesion sufficient to be cleanly removed from the attachment. It is desirable to have. And the pressure sensitive adhesive component may be a single pressure sensitive adhesive or may be a combination of two or more pressure sensitive adhesives.

Generally optically clear pressure sensitive adhesives are typically acrylate-based pressure sensitive adhesives. However, silicone based pressure sensitive adhesives, rubber resin based pressure sensitive adhesives, block copolymer based pressure sensitive adhesives, in particular those comprising hydrogenated elastomers, or vinyl ether polymer based pressure sensitive adhesives may also have optical transparency. Useful alkyl acrylates (ie, acrylic acid alkyl ester monomers) include linear or branched monofunctional unsaturated acrylates or methacrylates of non-tertiary alkyl alcohols having 4 to 14, especially 4 to 12 carbon atoms, alkyl groups. do.

In a preferred embodiment, the pressure sensitive adhesive is based on one or more poly (meth) acrylates. For example, it is a (meth) acrylic-acid pressure sensitive adhesive. Poly (meth) acrylic acid pressure sensitive adhesives are, for example, one or more alkyl (meth) acrylate ester monomers such as isooctyl acrylate, isononyl acrylate, 2-methyl-butyl acrylate, 2-ethyl n-hexyl acrylate and n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, n-octyl methacrylate, n-nonyl acrylate, isoamyl acrylate, n-decyl acryl Late, isodecyl acrylate, isodecyl methacrylate, isobornyl acrylate, 4-methyl-2-pentyl acrylate and dodecyl acrylate; And one or more optical co-monomer components such as (meth) acrylic acid, vinyl acetate, N-vinyl pyrrolidone, (meth) acrylamide, vinyl esters, fumarates, styrene macromers, alkyl maleates and alkyl fumars Derived from rate (based on maleic acid and fumaric acid, respectively), or combinations thereof.

Under certain conditions, the poly (meth) acrylic acid pressure sensitive adhesive may comprise about 0 to about 30 weight percent acrylic acid and about 100 to about 70 weight percent one or more isooctyl acrylate, 2-ethyl-hexyl acrylate or n-butyl acrylic Derived from the rate composition.

Preferred pressure sensitive adhesives of the invention are derived from about 2 to about 10 weight percent acrylic acid and about 90 to about 98 weight percent one or more isooctyl acrylate, 2-ethyl-hexyl acrylate or n-butyl acrylate composition .

Another preferred pressure sensitive adhesive of the present invention is derived from about 2 to 10 weight percent acrylic acid and about 90 to about 98 weight percent isooctyl acrylate. Another pressure sensitive adhesive includes about 70 wt% to 75 wt% phenoxy ethyl acrylate and about 25-30 wt% isooctyl acrylate, wherein the phenoxy ethyl acrylate and isooctyl acrylate total It may further comprise about 1 to about 5 parts by weight of acrylic acid per 100 parts by weight.

The pressure sensitive adhesive may be viscous in nature. If desired, thickeners may be added to the base material to form pressure sensitive adhesives. Useful thickeners include, for example, rosin ester resins, aromatic hydrocarbon resins, aliphatic hydrocarbon resins and terpene resins. Examples of other materials including other additives include oils, plasticizers, antioxidants, UV stabilizers, hydrogenated butyl rubbers, pigments, curing agents, polymer additives, thickeners, chain transfer agents and they reduce the optical transparency of pressure sensitive adhesives. If not, it can be added for a specific purpose.

UV absorbers used in the optical pressure-sensitive adhesive composition according to the present invention functions to absorb light in the region of 380nm or less that is the UV region. When a wavelength of 380 nm or less is scanned into the PDP filter, the dye or pigment for coloring inside is deformed to deteriorate the durability of the PDP. In addition, if the UV absorber that satisfies this is not properly used, the overall transmittance decreases or the haze rises, thereby degrading the function of the display which is the original purpose of the PDP. If the transmittance in the region of 380nm or more is lowered, visible light may be damaged and color reproducibility may be lowered, resulting in deterioration of product quality. In this case, when the transmittance of 5% or more was not able to sufficiently protect the internal structure, in order to solve this problem when the transmittance of 7% or less by the UV absorber, more preferably less than 5% Experimental results show that the structure of the PDP can be protected and the objective of selective transmission in the static region can be achieved.

In addition, if the haze is higher than 1.5% due to the UV absorber used, or less than 85% due to the low total transmittance, the screen of the display is uneven and the eyes are tired easily, or there is a lot of color loss. May damage the quality of the product.

Therefore, the researchers have shown that the optical properties due to the UV absorbers used, especially when Haze shows less than 1.5%, more preferably less than 1.0%, and the overall transmittance is more than 85%, more preferably more than 90%. I found that I did the implementation.

The stabilization mechanism of the UV stabilizer used at this time can be represented by the following two methods. First, a method of blocking ultraviolet energy, selectively absorbing ultraviolet energy and releasing it as other forms of energy that are not harmful to the polymer material, or suppressing the photolysis initiation reaction by suppressing chromophore of the activated polymer material. Light blocking agents, ultraviolet absorbers, etc. belong to this. Second, radical scavengers, peroxide decomposers, hindered amine stabilizers, etc. are included as a method of inhibiting photolytic growth reactions by reacting with free radicals or hydrogen peroxide to stop free radicals and decomposing peroxides during photodegradation.

UV stabilizers generally used include hydroxy benzophenone series and hydroxyphenyl benzotriazole series. Although benzophenone UV stabilizers have excellent compatibility with resins and are used in various ways, UV absorbing ability of 340 nm or more is inferior to benzotriazole UV stabilizers. Benzotriazole-based UV stabilizers are absorbable over a wide range and are mainly used for colorless and high-end products. In addition, there are ultraviolet absorbers such as resorcinol monobenzoate, salicylate, hydroxy benzoate and formamidine. In addition, free radical capture captures free radicals, which are the mediators of oxidation, unlike the previously described methods of eliminating energy sources. Typical UV stabilizers by free radical capture are hindered amines (HALS), which are easily oxidized to be converted to nitrooxy radicals and react with polymeric radicals to produce hydroxyamine ethers. Unlike UV absorbers, hindered amine UV stabilizers have excellent surface protection and can be applied to products with thin cross-sections. In addition, a cyclic imino ester compound having two carbon atoms constituting an aromatic nucleus and an imino ester ring as disclosed in US Pat. No. 4,446,262 may be used as an ultraviolet stabilizer. It has been reported that imino ester UV stabilizers have excellent thermal and oxidative stability.

As shown in the following experiment, it is difficult to maintain the appearance quality as the amount of UV absorber increases, and it is also shown that the quantitative selection is important according to the type of UV absorber. When prepared using randomized generalized pressure sensitive adhesives and UV absorbers described above, the visibility is poor, or it is difficult to show selective transmittance.

Accordingly, it is an object of the present invention to provide an optical pressure-sensitive adhesive composition having excellent transparency and visibility having a stable transmittance of less than 5% and a selective transmittance of less than 5% and a haze of less than 1% in the wavelength range of 380 nm or less and a total transmittance of 90% or more. It can be said that the technical features of the invention.

EXAMPLE

First, 30% of a hardening | curing material (epoxy) is added to 70 weight% of main materials (acrylate), and it stirs and makes a pressure-sensitive adhesive agent. The coating solution is prepared by adding 50% by weight of a solvent to the pressure-sensitive adhesive thus prepared. Thereafter, 1 part by weight, 3 parts by weight, and 5 parts by weight of the UV absorber were added to 100 parts by weight of the pressure-sensitive adhesive (excluding the base material + hardener), except for the solvent, to prepare a coating liquid for pressure-sensitive adhesive. .

The coating liquid for pressure-sensitive adhesive thus produced was applied to the film by a coater, and the film coated with the coating liquid was dried to remove the solvent added above, and then physical properties were measured.

Example 1

Hydroxyphenylbenzotriazole based UV absorber, based on 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the examples (base material + hardener), more specifically octyl-3- [ 3-tertiary-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (Octyl-3- [3- tert -butyl-4-hydroxy Adhesive composition which added -5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate).

Example 2

Hydroxyphenylbenzotriazole-based UV absorber, which is 1 part by weight of the UV absorber with respect to 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the embodiment (substrate + hardener), more specifically 2- (2- An adhesive composition to which hydroxy-3-tertiary-butyl-5-methylphenyl) -5-chlorobenzotriazole (2- (2-Hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole) is added.

Comparative Example 1

Hydroxyphenylbenzotriazole-based UV absorber, which is 1 part by weight of the UV absorber relative to 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the examples (substrate + hardener), more specifically, 2- (2H) Adhesive composition to which -benzotriazol-2-yl) -pi-cresol (2- (2H-benzotriazol-2-yl) -p-cresol) was added.

Comparative Example 2

Hydroxyphenylbenzotriazole-based UV absorber, which is 1 part by weight of the UV absorber based on 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the examples (substrate + light fire), more specifically 2- (2) H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (2- (2H-Benzotriazole-2- Adhesive composition to which yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol) is added

Comparative Example 3

Hydroxyphenylbenzotriazole-based UV absorber, which is 3 parts by weight of the UV absorber with respect to 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the embodiment (main material + hardener), more specifically 2- (2 H. Adhesive composition to which -benzotriazol-2-yl) -pi-cresol (2- (2H-benzotriazol-2-yl) -p-cresol) was added.

[Comparative Example 4]

Hydroxyphenylbenzotriazole-based UV absorber, which is 5 parts by weight of UV absorber based on 100 parts by weight of the pressure-sensitive adhesive during the preparation of the pressure-sensitive adhesive shown in the examples (substrate + hardener), more specifically, 2- (2H) Adhesive composition to which -benzotriazol-2-yl) -pi-cresol (2- (2H-benzotriazol-2-yl) -p-cresol) was added.

Table 1 shows the types and amounts of pressure-sensitive adhesives and UV absorbers used in the above Examples and Comparative Examples.

division Main adhesive components UV absorbers UV absorber amount (part by weight) Example 1 Poly (meth) acrylate Octyl-3- [3- tert -butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate One Example 2 Poly (meth) acrylate 2- (2Hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole One Comparative Example 1 Poly (meth) acrylate 2- (2Hbenzotriazol-2-yl) -p-cresol One Comparative Example 2 Poly (meth) acrylate 2- (2H-Benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol One Comparative Example 3 Poly (meth) acrylate 2- (2Hbenzotriazol-2-yl) -p-cresol 3 Comparative Example 4 Poly (meth) acrylate 2- (2Hbenzotriazol-2-yl) -p-cresol 5

As a result of the experiment using the examples and comparative examples, the transmittance, Haze, transmittance below 380nm and the appearance of the coating is shown in Table 2. (Circle) shows good, (triangle | delta) here and X is not good here.

division Transmittance Haze Transmittance below 380nm Coating appearance Overall rating Example 1 90.64 0.17 1.402 ○ ○ Example 2 90.47 0.20 2.00% ○ ○ Comparative Example 1 90.67 0.34 13.06 ○ X Comparative Example 2 90.62 0.15 7.16 ○ X Comparative Example 3 90.63 1.0 4.98 △ X Comparative Example 4 90.68 0.98 1.37 △ △

As can be seen from Table 2, in Example 1 and Example 2 of Table 2, the adhesive component having excellent transmittance, haze, transmittance below 380 nm, and appearance were all obtained. In addition, as shown in Comparative Example 1 and Comparative Example 2, depending on the type of the UV absorber, at 1 part by weight, such as 100 parts by weight of the poly (meth) acrylate pressure-sensitive adhesive, a desired UV absorption effect of 380 nm or less is obtained at 380 nm or less. As shown in Comparative Example 3 and Comparative Example 4, 5 parts by weight, preferably 3 parts by weight is required for the UV transmittance below 380 nm to be less than the desired 5%. . It was also shown that the clean appearance (transparency, appearance quality) of the coating deteriorates depending on the amount of UV absorber added.

In addition, as shown in Comparative Example 1, Comparative Example 3, and Comparative Example 4 of Table 2, the haze was increased as the amount of the UV absorber was increased, but the Haze increased rapidly in proportion to the amount of the UV absorber. It did not appear.

Experimental Example

Transmittance and Haze Test

Permeability and haze of all samples were measured using a Haze meter (NDH-300A). Given that the results of this experiment described are fabricated in a laboratory, anyone in this field expects that the production in the actual process will result in better appearance quality compared to the results in this experiment in the actual process. You can do it.

UV characteristic evaluation

In the evaluation of the UV characteristics in the region of 380 nm or less of all samples, the transmittance in the region of 380 nm or less was measured using a UV Visble Spectrometer, (Shimadzu, Japan).

Optical property test (reference)

The optical properties of the base as a reference point when base PET and glass microscope slides are used in the laminate were tested for visual transmission, haze. This value is shown in Table 3.

TABLE 3

materials Luminous transmittance (%) Haze (%) PET 89.0 0.8 Glass microscope slides 92.4 0.1

In the present specification, the present inventors describe only a few examples of various manufacturing and analysis experiments performed according to the manufacturing method according to the present invention, but the technical idea of the present invention is not limited thereto and is variously modified by those skilled in the art. Of course it can be implemented.

As described above, according to the optical pressure-sensitive adhesive composition according to the present invention, there is a very excellent effect of transparency and UV absorption.

In addition, it can be seen that the optical pressure-sensitive adhesive composition according to the present invention has a relatively simple and economical effect can be produced.

Claims (8)

delete delete delete A pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive based on poly (meth) acrylate and a hydroxyphenylbenzotriazole-based UV absorber that absorbs light in an area of 380 nm or less. 0.05 to 5 parts by weight of a UV absorber per 100 parts by weight of the pressure-sensitive adhesive, UV transmittance of less than 5% in the area of 380 nm or less, total Haze is less than 1%, the total transmittance is 90% Optical pressure-sensitive adhesive composition. The optical pressure-sensitive adhesive composition of claim 4, wherein the UV absorbent is 0.05 to 3 parts by weight per 100 parts by weight of the pressure-sensitive adhesive. delete The hydroxyphenylbenzotriazole-based UV absorbing agent according to claim 4, wherein the hydroxyphenylbenzotriazole-based UV absorber is octyl-3 [3-tertiary-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) Phenyl] propionate (Octyl-3- [3- tert- butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate) Adhesive composition. The hydroxyphenylbenzotriazole-based UV absorber according to claim 4, wherein the 2- (2-hydroxy-3-tertiary-butyl-5-methylphenyl) -5-chlorobenzotriazole (2- (2-Hydroxy-) 3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole), optical pressure-sensitive adhesive composition.