KR20170113805A - Optically clear adhesive composition, optically clear adhesive film and dual sided adhesive tape - Google Patents

Abstract

An acrylic copolymer resin as a copolymer of a mixed monomer component including an acid type monomer and a non-acid type monomer; And a photoinitiator are provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a transparent adhesive composition for optical use, a transparent adhesive film for optical use, and a double-sided adhesive tape. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

A transparent transparent adhesive film for optical use, and a double-faced adhesive tape.

2. Description of the Related Art In recent years, electronic devices such as a PDA, a mobile communication terminal, or a navigation system for a vehicle have formed a large market.

Such an electronic apparatus is provided with a touch screen or a touch panel switch on an input operation section above a display element panel, such as a liquid crystal display element (LCD). Accordingly, an adhesive sheet or an adhesive tape is used to adhere the touch screen panel to the display element panel or the light source, or an adhesive sheet or an adhesive tape is used to fix the bezel to the edge of the touch screen panel.

One embodiment of the present invention provides a composition for an optical transparent pressure-sensitive adhesive capable of realizing a pressure-sensitive adhesive exhibiting excellent initial adhesive force and excellent holding force property.

Another embodiment of the present invention provides an optical transparent pressure sensitive adhesive film produced from the above composition for optical transparent pressure sensitive adhesive.

Another embodiment of the present invention provides a double-sided pressure-sensitive adhesive tape using a transparent adhesive film for optical use produced from the above composition for optical transparent pressure-sensitive adhesive.

In one embodiment of the present invention, an acrylic copolymer resin as a copolymer of a mixed monomer component comprising an acid type monomer and a non-acid type monomer; And a photoinitiator for optical use.

The optical transparent pressure sensitive adhesive film produced from the above composition for optical transparent pressure sensitive adhesive exhibits excellent initial adhesive property and excellent holding property.

1 is a cross-sectional view of a double-sided adhesive tape according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

In the drawings of the present specification, the thicknesses are enlarged to clearly indicate layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Hereinafter, the formation of any structure in the "upper (or lower)" or the "upper (or lower)" of the substrate means that any structure is formed in contact with the upper surface (or lower surface) of the substrate However, the present invention is not limited to not including other configurations between the substrate and any structure formed on (or under) the substrate.

In one embodiment of the present invention, an acrylic copolymer resin as a copolymer of a mixed monomer component comprising an acid type monomer and a non-acid type monomer; And a photoinitiator for optical use.

The pressure-sensitive adhesive composition may be cured to form an adhesive film, a pressure-sensitive adhesive sheet, or a double-sided pressure-sensitive adhesive tape. Specifically, it is suitable for use as a double-sided pressure-sensitive adhesive tape for fixing a touch screen panel.

The adhesive sheet or double-sided adhesive tape produced from the pressure-sensitive adhesive composition may be used to fix the touch screen panel to the upper part of the display device panel or fix the display device panel to the upper part of the optical member or the like, Adhesive tapes exhibit excellent initial adhesion and retention characteristics.

The edge portion of the touch screen panel is fixed by a bezel. As the width of the bezel becomes narrower, improvement of initial adhesion is required. In addition, it is also required that such initial adhesion strength is maintained well.

The pressure-sensitive adhesive composition based on an acrylic resin using an acid type monomer has a strong cohesive force of the polymer itself, so that initial adhesive strength may be somewhat lowered, but retentive properties can be ensured. On the other hand, the pressure-sensitive adhesive composition based on an acrylic resin using a non-acid type monomer is superior to an pressure-sensitive adhesive composition based on an acrylic resin using an acid type monomer, but the property of holding force may be somewhat lowered.

The above composition for optical transparent pressure sensitive adhesive maintains a balance between the initial adhesive force and the holding force characteristic based on the acrylic copolymer resin using the acid type monomer and the anhydrous type monomer together, and both excellent characteristics can be realized.

In addition, since the mixed monomer component includes the acid type monomer and the anhydrous type monomer, the acid type monomer can improve the initial adhesion and the acid type monomer can improve the holding property, By being included in the composition for a transparent pressure-sensitive adhesive for optical, the whitening phenomenon can be prevented.

In one embodiment, the acid type monomer is a carboxyl group-containing (meth) acrylate, and the acid type monomer is a hydroxy group-containing (meth) acrylate.

Examples of the acid type monomer include (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid, Dimer, itaconic acid, fumaric acid, maleic acid, maleic anhydride, and combinations thereof.

The mixed monomer component may contain 5 to 15% by weight of the acid type monomer. The mixed monomer component may contain the acid type monomer as the content range to secure predetermined holding force characteristics.

Specific examples of the acid type monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, and combinations thereof .

The mixed monomer component may contain 5 to 30% by weight of the acid-free monomer. The mixed monomer component may contain the acid-free monomer as the content range to secure a predetermined initial adhesive property.

The weight ratio of the acid type monomer and the acid type monomer in the mixed monomer component may be 15:30 to 5: 5, specifically 10:20 to 8:10. By containing the acid type monomer and the acid type monomer in the content ratio of the mixed monomer component, it is possible to effectively prevent the white turbidity phenomenon.

The mixed monomer component may further include an alkyl (meth) acrylate monomer and an alicyclic (meth) acrylate monomer.

Specific examples of the alkyl (meth) acrylate monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n- (Meth) acrylate, isooctyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl .

The alicyclic (meth) acrylate monomer specifically includes one selected from the group including cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and combinations thereof doing

In one embodiment, the mixed monomer component comprises 60 to 70 wt% of an alkyl (meth) acrylate monomer, 15 to 30 wt% of an alicyclic (meth) acrylate monomer, 5 to 15 wt% of the acid type monomer, And 5 to 15% by weight of the monomer.

The acrylic copolymer resin may have a weight average molecular weight of about 2,000,000 to about 8,000,000.

The composition for optical transparency pressure sensitive adhesive composition may further contain additives such as an epoxy resin, a crosslinking agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant, a plasticizer and a combination thereof Lt; RTI ID = 0.0 > additive < / RTI >

In another embodiment of the present invention, there is provided a transparent adhesive film for optical use having a pressure-sensitive adhesive layer containing a photo-cured product of the composition for optical transparent pressure-sensitive adhesive.

The above pressure-sensitive adhesive composition can be cured by photocuring the above composition for optical pressure-sensitive adhesive. The photo-curing can be performed, for example, by UV irradiation. The UV irradiation carried out for photocuring can be carried out for about 10 seconds to about 15 seconds with a metal halide lamp, which is a commonly used metal halide lamp. The amount of the UV radiation is preferably about 1.0 J / cm ² to about 3.0 J / cm ² , and more preferably about 1.5 J / cm ² to about 2.5 J / cm ² .

As described above, the above-mentioned optical transparent adhesive film has excellent initial adhesive force, excellent holding force characteristics, and also effectively suppresses the whitening phenomenon.

In another embodiment of the present invention, a transparent substrate layer; And a pressure-sensitive adhesive layer formed on both sides of the transparent substrate layer and including a photo-cured product of the pressure-sensitive adhesive composition.

1 shows a cross section of the double-faced pressure-sensitive adhesive tape 100, which is a structure in which an adhesive layer 12 is laminated on both sides of a transparent substrate layer 11. [

The double-sided adhesive tape 10 can be used to fix the touch screen panel to an upper portion of the display element panel or fix the display element panel to an upper portion of an optical member or the like.

The transparent substrate layer 11 may be a transparent plastic film such as a polyethylene terephthalate (PET) film, a polycarbonate (PC) film, or a polyvinyl chloride (PVC) film.

The pressure-sensitive adhesive layer 12 may be formed by coating the transparent substrate layer 11 with the composition for optical transparent pressure-sensitive adhesive as described above to form the pressure-sensitive adhesive tape.

First, the acrylic copolymer resin is polymerized and then the remaining components are mixed to form the photo-curable pressure-sensitive adhesive composition, followed by film formation to produce a transparent adhesive film for optical use. The method for forming the film is not particularly limited, and for example, a casting method can be applied. Specifically, the above composition for optical transparent pressure sensitive adhesive is coated on a releasing film or a release paper by a usual means such as bar coats, knife coats, roll coats, spray coats, gravure coats, curtain coats, comma coats and / The film-forming step can be carried out. The film is formed in this manner, transferred to the transparent substrate layer 11, and then photo-cured to form the adhesive layer 12.

The thickness of the adhesive layer 12 may be about 10 탆 to about 100 탆.

The thickness of the transparent base layer 11 may be about 4 탆 to about 500 탆.

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 )

Example  One

A mixed monomer component containing 60% by weight of ethylhexyl acrylate, 20% by weight of isobornyl acrylate, 5% by weight of acrylic acid and 15% by weight of hydroxyethyl acrylate was placed in a 1 liter glass reactor and thermally polymerized to obtain an acrylic To obtain a copolymerized resin syrup. Cyclohexylphenyl-ketone (Igacure 184, BASF) as a photoinitiator was mixed with 100 parts by weight (based on solid content) of the obtained photo-curable acrylic copolymer resin and sufficiently stirred to prepare a composition for optical transparent pressure- . Subsequently, a composition for a transparent pressure-sensitive adhesive for photo-curable optics was formed to a thickness of 100 탆 and irradiated with light having a wavelength of 250 nm to be photo-cured to prepare a transparent adhesive film for optical use.

Comparative Example  One

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1, except that an acrylic copolymer resin was prepared by copolymerizing a mixed monomer component obtained by mixing 70% by weight of ethylhexyl acrylate, 25% by weight of isobornyl acrylate and 5% .

Comparative Example  2

Except that an acrylic copolymer resin was prepared by copolymerizing a mixed monomer component obtained by mixing 75 wt% of ethylhexyl acrylate, 15 wt% of isobornyl acrylate and 15 wt% of hydroxyethyl acrylate, To prepare a pressure-sensitive adhesive tape.

Comparative Example  3

It was attempted to prepare a composition for an optical transparent pressure sensitive adhesive by mixing the resin prepared in Comparative Example 1 with the resin prepared in Comparative Example 2,

evaluation

The optical transparency adhesive films produced in Example 1 and Comparative Examples 1-3 were evaluated for physical properties by the following evaluation methods and described in Table 1 below.

(1) Hardening degree measurement

With respect to the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the above Examples and Comparative Examples, the gel content [%] was measured by a dry-type method, and the method was as follows

Dry Breakfast:

(GEL,%) = (Later weight / (Initial weight) X100

In the above equation, the initial weight cured specimen is immersed in ethyl acetate and left for 24 hours at room temperature. The weight is an expanded mass which is the weight of the specimen left after being filtered using a 200 mesh wire net. The latter weight is filtered using a 200 mesh wire net And then drying the specimen left at 110 ° C for 2 hours.

(2) Evaluation of initial adhesion

In the above-mentioned pressure-sensitive adhesive films, each of the pressure-sensitive adhesive layers was attached to a polycarbonate (PC) substrate and kept at room temperature for 20 minutes. Then, the peel strength was measured at a rate of 300 mm / min to measure an initial adhesive force [kgf / in ² ]

(3) Evaluation of retention force

For the adhesive tape of the above example and the comparative example, two SUS substrates of 60 mm × 25 mm rectangles are prepared, and a specimen corresponding to 1 inch × 1 inch is attached to both sides. Two hours after the incubation, the chamber was placed in a high-temperature / high-humidity chamber under the condition of 85 ° C / 85%, and the time of dropout was measured.

(4) Evaluation of rebound characteristics

Specimens were prepared in the size of 150 mm * 20 mm for the adhesive tape prepared in Example 1 and Comparative Example 1-3, and then adhered to one end surface of an aluminum plate (155 mm * 30 mm * 0.5 mm), and then a 7 kg roller was reciprocated twice . A 7 kg roller was reciprocated twice after one side of the polycarbonate sheet (170 mm * 35 mm * 2 mm) was aligned with one end surface of the aluminum plate and the aluminum was attached to the center of the polycarbonate sheet. After being stored at room temperature for 24 hours, the specimen was placed on an aluminum test jig (210 mm * 165 mm * 5 mm) and placed in an 85 ° C 85% relative humidity chamber. In Table 1 below, when there is no widening, it is good, and when there is widening, it is described as poor.

(5) Evaluation of turbidity generation

It was visually observed whether clouding occurred.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Hardness (%) 50 52 68 When the resin is mixed, cloudiness occurs and all tests are impossible. Initial adhesive strength (g · mm) 40 18 60 retention 24 hours 24 hours 12 hours Resilience 4 hours 2 hours 10 minutes Occurrence of turbidity Not occurring Not occurring Not occurring Occur

Comparative Example 1 shows the case where acid type monomer is used, which is inferior in initial adhesion property but excellent in retention force characteristic, and Comparative Example 2 is in the case of using acid type monomer, and has excellent initial adhesion, but inferior retention characteristic. Example 1 exhibited retentive properties at the level of Comparative Example 1 and exhibited an initial adhesion characteristic superior to that of Comparative Example 1, but inferior to the initial adhesive strength at the level of Comparative Example 2. It was confirmed that the results of Example 1 demonstrate a predetermined initial adhesive force and holding force characteristics, and at the same time, the whitening phenomenon occurred in Comparative Example 3 did not occur.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And falls within the scope of the invention.

10: Double-sided adhesive tape
11: transparent substrate layer
12: Adhesive layer

Claims (15)

An acrylic copolymer resin as a copolymer of a mixed monomer component including an acid type monomer and a non-acid type monomer; And a photoinitiator.
The method according to claim 1,
Wherein the weight ratio of the acid type monomer and the acid type monomer in the mixed monomer component is from 15:30 to 5: 5
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the mixed monomer component comprises 5 to 15% by weight of the acid type monomer
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the mixed monomer component comprises 5 to 30% by weight of the acid-free monomer
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the acid type monomer is a carboxyl group-containing (meth) acrylate, and the acid type monomer is a (meth) acrylate containing a hydroxy group
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
The acid type monomer may be selected from the group consisting of (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid, Fumaric acid, maleic acid, maleic anhydride, and combinations thereof.
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
(Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, and combinations thereof.
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the mixed monomer component further comprises an alkyl (meth) acrylate monomer and an alicyclic (meth) acrylate monomer
A composition for a transparent pressure-sensitive adhesive for optical use.
9. The method of claim 8,
(Meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, Butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, and combinations thereof.
A composition for a transparent pressure-sensitive adhesive for optical use.
9. The method of claim 8,
Wherein the alicyclic (meth) acrylate monomer comprises one selected from the group consisting of cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate,
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the mixed monomer component comprises 60 to 70 wt% of an alkyl (meth) acrylate monomer, 15 to 30 wt% of an alicyclic (meth) acrylate monomer, 5 to 15 wt% of the acid type monomer, and 5 to 15 wt% Containing%
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
Wherein the photoinitiator comprises one selected from the group consisting of a benzoin-based initiator, a hydroxyketone-based initiator, an amino ketone-based initiator, a caprolactam-based initiator,
A composition for a transparent pressure-sensitive adhesive for optical use.
The method according to claim 1,
The composition for optical transparent pressure sensitive adhesive further comprises at least one additive selected from the group consisting of an epoxy resin, a crosslinking agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant, a plasticizer,
A composition for a transparent pressure-sensitive adhesive for optical use.
A transparent pressure-sensitive adhesive film for optical use having a pressure-sensitive adhesive layer comprising a photo-cured product of the composition for optical transparent pressure-sensitive adhesive according to any one of claims 1 to 13.
A transparent base layer; And
An adhesive layer formed on both sides of the transparent base layer and comprising a photo-cured product of the composition for optical transparent pressure-sensitive adhesive according to any one of claims 1 to 13;
Sensitive adhesive tape.

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