KR102147886B1 - Adhesive composition, and ultra-violet tunable and adhesive protective film using same - Google Patents

Abstract

The present invention relates to an adhesive composition and a UV variable adhesive protective film using the same, wherein the UV variable adhesive protective film obtained from the adhesive composition provides a stable initial adhesive force during the display panel manufacturing process, and can be easily peeled off by high-speed peeling at the end of the process. It has an adhesive force that does not exceed 100gf/inch so that it is possible. In addition, if necessary, the adhesive strength is reduced to 10gf/inch or less through UV irradiation so that it can be peeled more easily. It suppresses the generation of cracks on the display panel surface and does not leave any residue, thus improving the appearance characteristics of the display panel surface. Therefore, it can be usefully used as a protective film during the display panel manufacturing process.

Description

Adhesive composition and UV variable adhesive protective film using the same {ADHESIVE COMPOSITION, AND ULTRA-VIOLET TUNABLE AND ADHESIVE PROTECTIVE FILM USING SAME}

The present invention relates to an adhesive composition and a UV variable adhesive protective film using the same.

Various protective films are used during the manufacturing process of display panels.

Specifically, in the process of inverting the panel or attaching various chips to the rear, a protective film is attached to absorb the impact applied to the front of the panel and to prevent scratches or contamination by the conveyor. Depending on the type, the properties required for the protective film vary.

For example, since display panels made of glass or plastic are vulnerable to impact, protection with a thickness enough to absorb the impact applied during the process and an adhesive function that can effectively follow the steps created by various printing patterns or shapes. Film is required.

Various levels of adhesion are required for this protective film depending on the process conditions. For example, the protective film must be stably attached during the manufacturing process in order to effectively fill in the printing step on the display panel surface (to prevent lift phenomenon), and at the end of the work, without damaging the display panel (on the panel surface). It should be able to be easily removed so that no sticky residue remains.

On the other hand, the technique of removing the adhesive film by reducing the adhesive force by irradiating with UV is a known technique through a semiconductor dicing film. Specifically, the conventional dicing film has a function of stably fixing the semiconductor wafer by its self-adhesion, and then rapidly reducing the adhesive force through UV irradiation to facilitate picking after cutting (Korea Publication No. 2014- 0119182).

However, since the semiconductor dicing film initially realized a high adhesive force of several hundred gf/inch to completely fix the wafer, it was difficult to apply it as a protective film for display panel processing.

Korea Public Publication No. 2014-0119182

Therefore, the present invention effectively tracks the printing step on the surface of the display panel (prevents lifting), provides lamination stability, and enables easy peeling during high-speed peeling, and UV variable adhesive protection that can be easily peeled off by further lowering the adhesive force if necessary. It is intended to provide a film and an adhesive composition used in its production.

In order to achieve the above object, the present invention is a vinyl group-containing monomer is added bonded acrylic copolymer 100 parts by weight; 3 to 10 parts by weight of a diisocyanate-based curing agent; 0.1 to 5 parts by weight of slip agent; It provides a pressure-sensitive adhesive composition comprising; and 1 to 5 parts by weight of a photocuring initiator.

In order to achieve the above other object, the present invention is a base layer; UV variable adhesive layer formed from the adhesive composition; And it provides a UV variable adhesive protective film comprising a release film in a sequentially stacked form.

The UV variable adhesive protective film according to the present invention provides a stable initial adhesive force during the display panel manufacturing process, and has an adhesive force that does not exceed 100 gf/inch to enable easy peeling by high-speed peeling at the end of the process. In addition, if necessary, the adhesive strength is reduced to 10gf/inch or less through UV irradiation so that it can be peeled more easily. It suppresses the generation of cracks on the display panel surface and does not leave any residue, thus improving the appearance characteristics of the display panel surface. Therefore, it can be usefully used as a protective film during the display panel manufacturing process.

1 is a schematic diagram of a UV variable adhesive protective film according to an embodiment of the present invention.

The present invention is not limited to the contents disclosed below, and may be modified in various forms unless the gist of the invention is changed.

In the present specification, "including" means that other components may be further included unless otherwise specified. In addition, all numbers and expressions representing amounts of components, reaction conditions, and the like described in the present specification are to be understood as being modified by the term "about" in all cases unless otherwise specified.

Adhesive composition

The present invention is a vinyl group-containing monomer is added bonded acrylic copolymer 100 parts by weight; 3 to 10 parts by weight of a diisocyanate-based curing agent; 0.1 to 5 parts by weight of slip agent; It provides a pressure-sensitive adhesive composition comprising; and 1 to 5 parts by weight of a photocuring initiator.

The adhesive composition may have an adhesive strength of 100 gf/inch or less when cured with a coating film having a thickness of 20 to 80 μm, and may have an adhesive strength of 10 gf/inch or less when UV irradiation after curing.

Hereinafter, each component of the adhesive composition will be described in detail.

Vinyl -Containing monomer is added Combined Acrylic copolymer

The adhesive composition according to the present invention includes an acrylic copolymer to which a vinyl group-containing monomer is additionally bonded. The vinyl group-containing monomer may be a methacrylate containing an isocyanate group.

The acrylic copolymer to which the vinyl group-containing monomer is additionally bonded imparts adhesiveness to the adhesive composition due to adhesive properties peculiar to the acrylic resin. However, the vinyl group-containing monomer added to the copolymer increases the UV curability by actively causing a radical reaction upon UV irradiation, and thus the acrylic copolymer has a function of reducing the adhesive strength of the adhesive composition through UV irradiation. Perform.

The acrylic copolymer to which the vinyl group-containing monomer is additionally bonded is, for example, copolymerization of 2-ethylhexyl acrylate and butyl acrylate with a functional group monomer having a hydroxy group, and then the obtained copolymer is mixed with 2-isocyanate ethyl methacrylate. It may be an acrylic copolymer having an unsaturated double bond reactor prepared by addition reaction with a methacrylate containing an isocyanate group (vinyl group-containing monomer) such as.

The functional group monomer having a hydroxy group is hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3- Chloropropyl (meth) acrylate (2-hydroxy-3-chloropropyl (meth) acrylate), 4-hydroxybutyl (meth) acrylate (4-hydroxybutyl (meth) acrylate), glycerol (meth) acrylate (glycerol ( meth)acrylate), methyl α-hydroxy (meth)acrylate, ethyl α-hydroxy (meth)acrylate, propyl α- It may be hydroxy (meth) acrylate (propyl α-hydroxy (meth) acrylate), butyl α-hydroxy (meth) acrylate (butyl α-hydroxy (meth) acrylate), or a mixture thereof.

The methacrylate containing an isocyanate group is 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 2-isocyanatopropyl acrylate (2 -isocyanatopropyl acrylate), 2-(O-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate (2-(O-[1'-methylpropylideneamino]carboxyamino)ethylmethacrylate), 2-isocyanatoethyl 2 -Propenoate (2-isocyanatoethyl 2-propenoate), 1,1-bis (acryloyloxymethyl) ethyl isocyanate (1,1-bis (acryloyloxymethyl) ethyl isocyanate) or a mixture thereof.

Preferably, it may be 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, or a mixture thereof.

The acrylic copolymer to which the vinyl group-containing monomer is additionally bonded (acrylic copolymer having an unsaturated double bond reactive group) may have a weight average molecular weight of 300,000 to 1,500,000 g/mol.

Diisocyanate Hardener

The adhesive composition according to the present invention includes a diisocyanate-based curing agent.

The diisocyanate-based curing agent may be an aliphatic isocyanate compound containing two or more functional groups, an alicyclic isocyanate compound, an aromatic isocyanate compound, and the like.

Specifically, the diisocyanate-based curing agent is toluene diisocyanate, methylenediphenyl diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate trimer, toluene diisocyanate trimer, isophorone diisocyanate. It may be an isocyanate trimer or mixtures thereof. More specifically, it may be a hexamethylene diisocyanate trimer or an isophorone diisocyanate trimer.

The hexamethylene diisocyanate trimer is more advantageous in terms of securing flexibility to increase the curing density of the adhesive layer and improve step followability, and the isophorone diisocyanate trimer has a slow reaction rate, but is advantageous when forming a hard film.

The curing agent may be included in an amount of 3 to 10 parts by weight, 3 to 8 parts by weight, or 3 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer to which the vinyl group-containing monomer is added. When within the above range, when the adhesive composition is coated and cured, an initial adhesive strength of 100 gf/inch or less may be provided.

Slip agent

The adhesive composition according to the present invention includes a slip agent. The slip agent imparts a slip property (slip property) to the adhesive composition.

The slip agent may be obtained through a combination of at least one selected from the group consisting of an organic-modified polydimethylsiloxane-based compound, a fluorine-modified polyacrylate-based compound, and a perfluoro polyether (PFPE)-based compound.

The slip agent may be a polydimethylsiloxane-based compound containing a hydroxy functional group. The polydimethylsiloxane-based compound including the hydroxy functional group may have a weight average molecular weight of 1,000 to 50,000 g/mol or 10,000 to 50,000 g/mol.

The polydimethylsiloxane-based compound containing the hydroxy functional group may be combined with the acrylic copolymer to which the vinyl group-containing monomer is added and transferred to the surface of the adherend, thereby preventing deterioration of the surface properties of the adherend.

The slip agent may be included in an amount of 0.1 to 5 parts by weight, 0.1 to 3 parts by weight, or 0.1 to 1.5 parts by weight based on 100 parts by weight of the acrylic copolymer to which the vinyl group-containing monomer is added. When within the above range, when the adhesive composition is coated and cured, an initial adhesive strength of 100 gf/inch or less may be provided.

Photocuring Initiator

The adhesive composition according to the present invention includes a photocuring initiator so that it can be photocured through UV irradiation.

The photocuring initiator is preferably a radical photopolymerization initiator, but is not limited thereto. The photocuring initiator is 1-hydroxy-cyclohexyl phenylketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, methyl formate, 1-phenyl-1,2-propenedione, benzyl It may be dimethyl ketal, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, benzophenone, or a mixture thereof.

When the photocuring initiator is a mixture of 1-hydroxy-cyclohexyl phenylketone and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, the 1-hydroxy-cyclohexyl phenylketone and bis(2 The weight ratio of ,4,6-trimethylbenzoyl)-phenylphosphine oxide may be 2:1 to 4:1.

The photocuring initiator may be included in an amount of 1 to 5 parts by weight, 1 to 3 parts by weight, or 1 to 2 parts by weight based on 100 parts by weight of the acrylic copolymer to which the vinyl group-containing monomer is additionally bonded. When within the above range, after photocuring by UV irradiation, the adhesive strength may be reduced to 10 gf/inch or less.

UV variable adhesive protective film

The present invention can obtain a UV variable adhesive protective film by using the adhesive composition as described above. Specifically, the present invention is a base layer; UV variable adhesive layer formed from the adhesive composition; And it provides a UV variable adhesive protective film comprising a release film in a sequentially stacked form.

Base layer

The UV variable adhesive protective film according to the present invention may include a substrate layer of a generally used protective film, for example, a plastic film as a substrate layer.

The base layer may be a plastic film such as polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), and specifically PET. PET is advantageous in terms of durability, mechanical strength, and transparency.

The thickness of the base layer may be 188 μm or less, 125 μm or less, 100 μm or less, 50 to 188 μm, 50 to 125 μm, or 50 to 100 μm.

In consideration of the handleability and flexibility aspects, it is preferably 125 μm or less, and in order to effectively protect the panel from being pressed by lamination and to ensure adequate flexibility, the range of 50 to 100 μm is more preferable.

UV variable type Adhesive layer

The UV variable adhesive protective film according to the present invention includes a UV variable adhesive layer obtained from the adhesive composition.

Detailed description of the adhesive composition is the same as described above.

The adhesive layer may be obtained by curing the adhesive composition with a coating film on one surface of the base layer. Specifically, the adhesive layer may be formed by heat drying and curing at 100 to 130°C, or 110 to 120°C for 1 to 5 minutes, or 1 to 3 minutes after applying the adhesive composition on the base layer. .

The adhesive layer may have a thickness of 20 to 80 µm, 30 to 70 µm, 50 to 80 µm, or 50 to 75 µm. When within the above range, the display panel can be effectively protected from physical impacts such as pressing and stamping. I can.

The adhesive layer has an adhesive strength of 100 gf/inch or less, 90 gf/inch or less, 85 gf/inch or less, 30 to 100 gf/inch, 30 to 90 gf/inch, or 30 to 80 gf/inch, and 10 gf/inch or less after UV irradiation, It may have an adhesive strength of 8 gf/inch or less, 7 gf/inch or less, 1 to 10 gf/inch, 1 to 8 gf/inch, or 1 to 7 gf/inch.

The protective film includes a UV-variable adhesive layer having the adhesive force as described above, so that it can be easily peeled off by high-speed peeling in the latter part of the process, and if necessary, the adhesive strength is more effectively reduced through UV irradiation and can be removed more easily. have.

Release film

The UV variable adhesive protective film according to the present invention may include a release film formed on one side of the adhesive layer, and specifically may include a base layer, an adhesive layer, and a release film in a sequentially stacked form.

The release film may be a plastic film, such as polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), etc., and specifically, silicone-coated PET It can be a film.

The release film may have a thickness of 25 to 100 μm, or 25 to 50 μm.

The release film may have a peel force of 10 to 30 gf/inch or less based on Tesa 7475.

In the above range, it may not be separated from the adhesive layer alone during the punching process for forming a sheet, and it may be easy to peel the release film during the lamination process.

Antistatic layer

The UV variable adhesive protective film according to the present invention may further include an antistatic layer to prevent adsorption of foreign substances.

Specifically, the adhesive protective film may further include an antistatic layer on the other surface of the base layer (a surface opposite to the contact surface with the adhesive layer).

The antistatic layer may be formed by coating a conventionally known material such as a conductive polymer (eg, poly(3,4-ethylenedioxythiophene) (PEDOT)) and an ionic liquid on the other surface of the substrate layer. It can be formed by coating the PEDOT-containing composition on the other surface of the substrate layer.

The antistatic layer may have a surface resistance of 10^12 Ω/□ or less, 10^10 Ω/□ or less, 10^5 to 10^12 Ω/□, or 10^5 to 10^10 Ω/□. When it is in the above range, it is more advantageous in terms of the effect of inhibiting foreign matter adsorption.

The UV-variable adhesive protective film may be prepared by applying the adhesive composition to one surface of a base layer and heat-drying to form an adhesive layer, and then laminating a release film on one surface of the adhesive layer.

As an application method, for example, a gravure roll coating method, a Mayer bar coating method, a blade coating method, a curtain coating method, a comma coating method, a slot die coating method, etc. can be used, and the comma coating method in consideration of the thickness of the adhesive layer Or slot die coating may be preferred.

As described above, the UV variable adhesive protective film according to the present invention provides a stable initial adhesive force during the display panel manufacturing process, and has an adhesive strength not exceeding 100 gf/inch to enable easy peeling by high-speed peeling in the late process. In addition, if necessary, the adhesive strength is reduced to 10gf/inch or less through UV irradiation so that it can be peeled more easily. It suppresses the generation of cracks on the display panel surface and does not leave any residue, thus improving the appearance characteristics of the display panel surface. Therefore, it can be usefully used as a protective film during the display panel manufacturing process. In addition, the protective film may protect the panel from physical impact during the manufacturing process, and effectively follow a step difference due to a bezel area or a printing area to prevent lifting.

The above will be described in more detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the examples is not limited thereto.

[ Example ]

Example 1. Preparation of adhesive composition

100 parts by weight of an acrylic copolymer (SA 105, MW: 700,000 to 800,000 g/mol, Samwha Paint) to which a vinyl group-containing monomer is added, 3.5 parts by weight of hexamethylene diisocyanate trimer SC100I (Samhwa Paint) as a diisocyanate-based curing agent , 1-hydroxycyclohexyl phenylketone (Igacure 184, BASF) and bis(2,4,6-trimethylmenzoyl)-phenylphosphine oxide (Igacure 819, BASF) as a photocuring initiator of 3:1 2 parts by weight of the mixture mixed at a weight ratio and 1 part by weight of BYK377 (BYK) as a slip agent were uniformly mixed to prepare an adhesive composition.

Example 2 and Comparative example 1 to 3. Preparation of adhesive composition

As shown in Table 1 below, an adhesive composition was prepared in the same manner as in Example 1, except that the content of each raw material was adjusted differently.

[ Evaluation example ]

1. Adhesion evaluation

Prepare a 75 μm-thick polyethylene terephthalate (PET) substrate layer and a 25 μm-thick release film (RF02N, SKC hi-tech&marketing), and place the adhesive layer between the substrate layer and the release film on one side of the substrate layer. The adhesive composition prepared in Example 1 was applied and thermally dried at 120° C. for 3 minutes to prepare a protective film so that the dry thickness of the adhesive layer was 75 μm.

After removing the release film from the protective film, attach it to an alkali-free glass (glass plate) by reciprocating twice using a 2Kg roll, and leave it for 30 minutes in an atmosphere of 25°C and 50% relative humidity, and then at a speed of 300 mm/min at a 180° angle. The adhesive strength (initial adhesive strength) when the adhesive layer was peeled off was measured, and after irradiating the accumulated light amount of 500 mJ/cm ² with a metal halide UV lamp, the adhesive strength was measured in the same manner.

For the adhesive compositions of Example 2 and Comparative Examples 1 to 3, a protective film was prepared in the same manner to measure initial adhesive strength and adhesive force after UV irradiation.

2. Surface contamination evaluation

After removing the release film from the protective film prepared in Evaluation Example 1, it was attached to an alkali-free glass, and left for 96 hours at 60° C. and 90% relative humidity. Thereafter, the protective film was removed and the degree of contamination on the surface of the glass plate was visually checked under 3-wavelength illumination. If no stains or residues remain, pass, visible stains or whitening, and residuals of the adhesive layer were evaluated as NG.

3. After high-speed peeling Of the deposited layer surface crack Whether to evaluate

After removing the release film from the protective film prepared in Evaluation Example 1, the film was laminated by reciprocating and reciprocating twice in a 2Kg roll on the deposition surface of the film on which the silicon oxide was deposited, and then allowed to stand in an environment of 25°C and 50% relative humidity for 24 hours. The protective film was peeled off by peeling at a high speed of 10 m/min at a 180° angle, and it was checked whether the deposition surface cracked on the surface from which the protective film was peeled off.

Looking at the results of Table 1, the protective films prepared with the adhesive compositions of Examples 1 and 2 showed an initial adhesive strength of 100 gf/inch or less, and surface contamination such as whitening was not observed when removed after deposition on a glass plate or film. It can be seen that the residue was not left and defects such as cracks did not occur, so it was easily peeled off.

On the other hand, all of the protective films made of the compositions of Comparative Examples 1 to 3 exhibited excessive adhesion exceeding 100 gf / inch. In addition, as a result of evaluating the degree of surface contamination and whether or not cracks, it was confirmed that the protective film was not neatly peeled off such as whitening phenomenon occurred on the surface of the glass plate (Comparative Example 1), or cracks occurred after high-speed peeling.

In addition, the protective films prepared with the compositions of Examples 1 and 2 effectively reduced adhesion to less than 10 gf/inch after UV irradiation, whereas the protective films prepared with the compositions of Comparative Examples 1 to 3 all exceeded 10 gf/inch. It was confirmed that the adhesive strength was not significantly reduced even after UV irradiation as the adhesive strength was shown, and the adhesive strength of up to 39 gf/inch was shown.

Claims (10)

100 parts by weight of an acrylic copolymer to which a vinyl group-containing monomer is added;
3 to 10 parts by weight of a diisocyanate-based curing agent;
0.1 to 5 parts by weight of slip agent; And
As an adhesive composition comprising 1 to 5 parts by weight of a photocuring initiator,
The slip agent is a polydimethylsiloxane-based compound containing a hydroxy functional group,
The adhesive composition has an adhesive strength of 100 gf/inch or less when cured with a coating film having a thickness of 20 to 80 µm, and has an adhesive strength of 10 gf/inch or less when UV irradiation after curing. delete The method of claim 1,
The acrylic copolymer to which the vinyl group-containing monomer is additionally bonded has a weight average molecular weight of 300,000 to 1,500,000 g/mol. The method of claim 1,
The adhesive composition, wherein the vinyl group-containing monomer is a methacrylate containing an isocyanate group. delete According to 1,
The photocuring initiator is a mixture of 1-hydroxy-cyclohexyl phenylketone and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the 1-hydroxy-cyclohexyl phenylketone and bis(2, The weight ratio of 4,6-trimethylbenzoyl)-phenylphosphine oxide is 2:1 to 4:1, the adhesive composition. Base layer; A UV variable adhesive layer formed from the adhesive composition of any one of claims 1, 3, 4 and 6; And comprising a release film in a sequentially laminated form, UV variable adhesive protective film. delete The method of claim 7,
The release film has a peeling force of 10 to 30 gf / inch based on Tesa 7475, UV variable adhesive protective film. The method of claim 7,
The adhesive protective film further includes an antistatic layer on the other surface of the base layer, and the antistatic layer has a surface resistance of 10^12 Ω/□ or less, a UV variable adhesive protective film.

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