KR102398470B1 - Pressure sensitive adhesive composition, protective film using the same, and production method of protective film using the same - Google Patents

Abstract

As a pressure-sensitive adhesive composition in the present specification, based on the total content of the composition, 30-50% by weight of an acrylic monomer; 0.5-10 wt% of an unsaturated monomer containing a carboxyl group and a hydroxyl group; 0.5-3.0 wt% of an isocyanate-based curing agent; And 0.1-2.0% by weight of an ionic charge agent; is provided a pressure-sensitive adhesive composition comprising a.

Description

A pressure-sensitive adhesive composition, a protective film using the same, and a method for manufacturing a protective film using the same

The present specification relates to a pressure-sensitive adhesive composition, a protective film using the same, and a method for manufacturing a protective film using the same, and more specifically, it contains an antistatic agent to provide excellent adhesion, and there is no burr or steaming during cutting, so fairness is improved. It is secured and relates to a pressure-sensitive adhesive composition having excellent peel electrification voltage characteristics, a protective film using the same, and a method for producing a protective film using the same.

In general, an adhesive protective film for protecting a surface is attached to an electronic component or the like. The adhesive protective film is particularly suitable for use in display panels such as LCD panels (Liquid Crystal Display Panel) and PDP (Plasma Display Panel) constituting display devices such as mobile phones, computer monitors, TVs, and various advertisement boards. is increasing rapidly.

Conventionally, a triacetyl cellulose (TAC, triacetyl cellulose)-based film has been mainly used as a display protection film, but there is a problem in that such a TAC film is easily deformed in a high temperature and high humidity environment. Therefore, in recent years, protective films of various materials that can replace the TAC film have been developed, for example, polyethylene terephthalate (PET), cycloolefin polymer (COP, cycloolefin polymer), an acrylic film, etc. alone Or a method of using a mixture has been proposed.

On the other hand, these protective films have a problem in that the adhesive strength between the PVA film and the water-based adhesive, which has been mainly used for bonding the protective film in the prior art, is not sufficient. In order to solve this problem, a method for improving adhesion with a water-based adhesive is proposed by forming a silicone-based pressure-sensitive adhesive layer on the surface of polyethylene terephthalate (PET), cycloolefin polymer (COP), acrylic film, etc. and the silicone-based pressure-sensitive adhesive layer has advantages such as excellent heat resistance and weather resistance.

In addition, as the current display panel is thinned, there is a problem of static electricity occurring during peeling of the protective film that affects the liquid crystal arrangement and the sensor. Since the static electricity generated when the protective film is peeled may damage the upper or lower panel, the demand for static electricity management in the display panel manufacturing field is increasing.

Therefore, in the present invention, an ionic charging agent is added to the acrylic monomer, and the content of the isocyanate-based curing agent is minimized to secure the fluidity of ions having chargeability, so that when the protective film is peeled off, the peeling electrification voltage is less than 0.4Kv and the surface resistance of PSA It is intended to provide an adhesive film that can minimize the value of 109Ω or less, and an adhesive film that can secure wettability at an Ra value of 0.5㎛ ~ 2um with a relatively large roughness of the adherend.

Through this, it is possible to shorten the cleaning process at the time of the second bonding without leaving a residue of the adhesive layer even after the tape is peeled, thereby improving the efficiency.

One embodiment of the present invention, the pressure-sensitive adhesive composition, based on the total content of the composition, 30-50% by weight of an acrylic monomer; 0.5-10 wt% of an unsaturated monomer containing a carboxyl group and a hydroxyl group; 0.5-3.0 wt% of an isocyanate-based curing agent; And 0.1-2.0 wt% of an ionic charge agent; Containing, a pressure-sensitive adhesive composition is provided.

In one embodiment, 0.1-1.0 wt% of an isocyanate-based curing agent may be included with respect to the total content of the composition.

In one embodiment, 0.1-2.0 wt% of an ionic charge agent based on the total content of the composition; may include.

In one embodiment, the isocyanate-based curing agent may include one or more curing agents selected from the group consisting of torylene diisocyanate, xylene diisocyanate, and hexamethylene diisocyanate. there is.

In one embodiment, the ionic charge agent may include one or more curing agents selected from the group consisting of metal salts, amine-based or pyridine-based charge agents.

Another embodiment of the present invention provides a protective film comprising; a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to an embodiment of the present invention.

In one embodiment, the base film is polyethyleneterephthalate (PET), polybutyleneterephthalate (PBT), polyethylenenaphthalate (PEN), polybutylenenaphthalate (PBN), polyethylene ( polyethylene: PE), polypropylene (polypropylene: PP), and polyimide (polyimide) may include one or more selected from the group consisting of.

In one embodiment, the pressure-sensitive adhesive layer may have adhesion to an adherend having an Ra value of 0.5-2 μm.

In one embodiment, the protective film may further include a release film layer on the pressure-sensitive adhesive layer.

In one embodiment, the protective film may have a measured value of tack 　 adhesive force of 40 gf or more at 25°C.

In one embodiment, the protective film may have a peel electrification voltage of 0.3 kv or less.

In one embodiment, the protective film may have a surface resistance of 10 ⁹ Ω or less.

Another embodiment of the present invention comprises the steps of preparing a base film; and forming a pressure-sensitive adhesive layer including the pressure-sensitive adhesive composition according to an embodiment of the present invention on the base film;

In one embodiment, the process speed of forming the pressure-sensitive adhesive layer may be 5 m/min or less.

In one embodiment, before forming the pressure-sensitive adhesive layer, forming a primer layer comprising a urethane-based resin on the base film; may further include.

According to exemplary embodiments of the present invention, it contains an acryl-based monomer, an unsaturated monomer containing a carboxyl group and a hydroxyl group, an isocyanate-based curing agent, and an ionic charge agent to increase adhesion with the base film and at the same time have an excellent peel electrification voltage protective film It is possible to manage the static electricity problem that occurs during peeling.

1 shows a schematic diagram of a protective film according to an embodiment of the present invention.
FIG. 2 is an SEM view showing that a major component is precipitated when a protective film according to an embodiment of the present invention is attached to an adherend.
FIG. 3 shows the result of component analysis by EDS that a major component is precipitated when a protective film according to an embodiment of the present invention is attached to an adherend.
4A and 4B are photographs of surface roughness using 2D and 3D, respectively. Specifically, FIG. 4a shows the roughness Ra of the surface was measured using 2D, and FIG. 4b is a 3D photograph of the surface. In other words, the surface roughness is 0.6um, and it is a figure measured by selecting an adherend with high roughness.
5A and 5B show a case in which a protective film according to an embodiment of the present invention is attached to an adherend having a Ra of 0.6 μm, and shows good adhesion ( FIG. 5A ) and the case of poor adhesion due to generation of microbubbles. (Fig. 5b) is shown respectively.
6 is a hardness test of the protective film according to an embodiment of the present invention, and shows the results of pencil testing of specimens of evaluation criteria H1 (left), S1H1 (center), and S2H1 (right), respectively.

Term Definition

In the present specification, the "pressure-sensitive adhesive layer" is not particularly limited as long as it is a film having adhesive strength and elasticity. "Pressure-sensitive adhesive" means an adhesive that adheres to the surface of an adherend just by applying pressure, and can be removed from the adherend without leaving almost no traces on the adherend by applying an appropriate strength.

As used herein, the term “burr” refers to rubber molding residues, and refers to fine powders, residues, etc. generated in parts such as cut materials during a process such as film cutting.

As used herein, "steamed" means that some components of the pressure-sensitive adhesive stick to the adherend or knife when cutting the pressure-sensitive adhesive, and steamed corresponds to an intermediate state between a solid and a liquid when compared to a solid-type burr.

Hereinafter, embodiments of the present invention will be described in more detail.

The embodiments of the present invention disclosed in the text are illustrated for the purpose of explanation only, and the embodiments of the present invention may be embodied in various forms and should not be construed as being limited to the embodiments described in the text. .

The present invention can make various changes and can have various forms, and the embodiments are not intended to limit the present invention to a specific disclosed form, and all changes, equivalents or substitutes included in the spirit and scope of the present invention should be understood as including

adhesive composition

One embodiment of the present invention, the pressure-sensitive adhesive composition, based on the total content of the composition, 30-50% by weight of an acrylic monomer; 0.5-10 wt% of an unsaturated monomer containing a carboxyl group and a hydroxyl group; 0.5-3.0 wt% of an isocyanate-based curing agent; And 0.1-2.0 wt% of an ionic charge agent; Containing, a pressure-sensitive adhesive composition is provided.

In an exemplary embodiment, the pressure-sensitive adhesive composition may include 30-50 wt% of an acrylic monomer based on the total content of the composition. If the content of the acrylic monomer is less than 30% by weight, sufficient crosslinking reaction does not occur and may impair the adhesive properties of the acrylic. long-term reliability may be compromised.

In an exemplary embodiment, the acrylic monomer may include an acrylic acid ester monomer, for example, a (meth)acrylic acid ester monomer. Specifically, the (meth) acrylic acid ester monomer is butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) ) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, selected from the group consisting of decyl (meth) acrylate, etc. It may include one or more being.

In addition, the pressure-sensitive adhesive composition may include 0.5-10% by weight of an unsaturated monomer containing a carboxyl group and a hydroxyl group, based on the total content of the composition. If the weight of the carboxyl group and hydroxyl group-containing unsaturated monomer is less than 0.5 wt%, crosslinking may not occur because sufficient reaction with NCO of the isocyanate curing agent does not occur, and if it exceeds 10 wt%, unreacted carboxyl group and hydroxyl group after sufficiently reacting with NCO There is a possibility of causing problems by causing transfer to the remaining adherend.

In an exemplary embodiment, the unsaturated monomer containing a carboxyl group and a hydroxyl group may be an ethylenically unsaturated compound monomer containing an acid functional group. For example, as a polyester-based oligomer, it may be an oligomer having a carboxyl group and an unsaturated bond. Specifically, the carboxyl group contained in the unsaturated monomer may undergo a urea reaction with an isocyanate group (-NCO), as shown in Formula 1 below. .

In addition, the hydroxyl group contained in the unsaturated monomer may undergo a urethane reaction with an isocyanate group (-NCO), as shown in Chemical Formula 2 below.

Through the urea reaction and the urethane reaction, the unsaturated monomer containing a carboxyl group and a hydroxyl group may be cross-linked with an isocyanate-based curing agent.

In an exemplary embodiment, the isocyanate-based curing agent may include an isocyanate compound, an epoxy compound, a metal compound, etc., specifically, the isocyanate compound is torylene diisocyanate, xylene diisocyanate ( It may include an adduct with an aromatic diisocyanate such as xylene diisocyanate, hexamethylene diisocyanate, or a compound having a hydroxyl group. For example, the isocyanate-based curing agent may include one or more curing agents selected from the group consisting of torylene diisocyanate, xylene diisocyanate, and hexamethylene diisocyanate. . Specifically, the isocyanate-based curing agent is an aliphatic isocyanate compound such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate (TMDI), diphenylmethane diisocyanate (MDI), xylyl It may include one or more curing agents selected from the group consisting of rendiisocyanate (XDI), dimethyldiphenylenediisocyanate (TOID), and tolylenediisocyanate.

Also, in an exemplary embodiment, 0.5-3.0% by weight of an isocyanate-based curing agent, for example, 0.5-2.0% by weight, may be included, preferably 0.1-1.0% by weight of an isocyanate-based curing agent, based on the total content of the composition. there is. When the content of the isocyanate-based curing agent is less than 0.5% by weight, the curing density is low and the adhesive layer passes over the adherend, and constant adhesive strength or physical properties may not be maintained. It may produce bad results for long-term reliability, and it is also not good from an economic point of view.

In particular, when the isocyanate-based curing agent is included in the above range, it can be optimized in tack adhesive strength and crosslinking amount, and accordingly, the adhesive film according to an embodiment of the present invention has a tack 　 adhesive force of 40 gf or more, By including 0.5-3.0 wt% of an isocyanate-based curing agent based on the total content of the composition, excellent tack adhesion and crosslinking properties can be achieved at the same time.

In an exemplary embodiment, the ionic charging agent is included in the pressure-sensitive adhesive composition to secure a low peel electrification voltage, and there is no burr and steam generation during film cutting, thereby ensuring good processability.

In an exemplary embodiment, the ionic charge agent may include a metal salt, an amine-based charge agent, or a pyridine-based charge agent. Specifically, the ionic charge agent may include one or more charge agents selected from the group consisting of pyridine series. The ionic charging agent can minimize the peeling charging voltage and the surface resistance value of the pressure-sensitive adhesive layer when the protective film is peeled off by securing the fluidity of ions having chargeability.

In addition, the ionic charge agent may include at least one selected from the group consisting of a metal salt having a metal ion, an ionic liquid, a carbon material, and a surfactant, and the metal salt includes a lithium salt, a lithium imide ( Lithium imide) and potassium salt may be cited as examples, and the ionic liquid may include pyridine imide and the like. Specifically, the metal salt may be a lithium salt, and specifically, lithium iodide (LiI), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), lithium hexafluoroalsenate (LiAsF ₆ ) , lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluorophosphate (LiPF ₆ ), sodium hexafluorophosphate (NaPF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), bis(trifluoromethane) Sulfonyl)imilithium (LiN(CF ₃ SO ₂ ) ₂ ), tris(trifluoromethanesulfonyl)methidridium (LiC(CF ₃ SO ₂ ) ₃ ), bis(fluorosulfonyl)imide potassium from the group consisting of (KaN(FSO ₂ ) ₂ ), sodium bis(fluorosulfonyl)imide (NaN(FSO ₂ ) ₂ ) and bis(fluorosulfonyl)imilithium (LiN(FSO ₂ ) ₂ ) It may be one or more selected.

In an exemplary embodiment, 0.1-2.0% by weight of an ionic charge agent based on the total content of the composition; may include. If the ionic charge content is less than 0.1% by weight, more than 2Kv of static electricity may be generated, and if it is more than 2.0% by weight, it may be difficult to control further low static electricity beyond the critical point.

protective film

Another embodiment of the present invention provides a protective film 100 including; a pressure-sensitive adhesive layer 120 including the pressure-sensitive adhesive composition according to an embodiment of the present invention. For example, the protective film may be laminated in the order of the base film 110 and the pressure-sensitive adhesive layer 120 . 1 shows a schematic diagram of a protective film according to an embodiment of the present invention, which will be described with reference to this.

The base film 110 uses a high elastic modulus, a small hygroscopic expansion coefficient, and a small linear expansion coefficient. In particular, it is preferable to use a fabric having optical properties and not using a recycled chip.

In an exemplary embodiment, the base film 110 may include polyethyleneterephthalate (PET), polybutyleneterephthalate (PBT), polyethylenenaphthalate (PEN), and polybutylenenaphthalate (PBN). ), polyethylene (PE), polypropylene (PP), and polyimide (polyimide) may include at least one selected from the group consisting of. Preferably, the strength of the base film 110 is 15 kgf/15 mm or more in the MD direction, 20 kgf/15 mm or more in the TD direction, and the elongation may be a polyethylene terephthalate film having less than 120% of the MD direction and TD direction.

In an exemplary embodiment, the thickness of the base film 110 may be 65 to 85 μm or more. If the thickness is less than 65㎛, it may be damaged due to handling problems during process work.

In an exemplary embodiment, the thickness of the pressure-sensitive adhesive layer 120 may be 100 μm or more, and may be 200 μm or less. If the thickness of the pressure-sensitive adhesive layer 120 is less than 100 μm, it may be vulnerable to external impacts (pinholes, press, etc.) Non-curing may occur in the layer, which may lower the physical properties of the adhesive protective film.

In an exemplary embodiment, the pressure-sensitive adhesive layer 120 may have adhesion to an adherend having an Ra value of 0.5-2 μm. Specifically, the pressure-sensitive adhesive layer may have excellent adhesion even on an adherend with high roughness, for example, the measured value of tack and adhesive force at 25° C. may be 40 gf or more, for example, it may be in the range of 40 gf to 100 gf there is. When it has a tack adhesive force in the above range, it may have excellent adhesion even to an adherend having a high roughness. The tack adhesive force may be a value obtained by measuring the tack by laminating a sample of 40 mm * 40 mm to the sus head using a probe tack equipment at 25°C. On the other hand, "tack" is called initial adhesive force or instantaneous adhesive force, etc., and is one of the main properties of the adhesive. This tack refers to the property of sticking to the adherend in a short time by simply touching the adherend very lightly. A strong initial tack means that it has an adhesive force that can withstand practical use immediately after bonding.

On the other hand, in order to prevent the pressure-sensitive adhesive layer from being transferred to the adherend, the pressure-sensitive adhesive composition must be sufficiently crosslinked. Specifically, the amount of crosslinking is related to the content of the isocyanate-based curing agent, and when an isocyanate-based curing agent is added in excess, the tack adhesion may be lowered. There may be a problem that the pressure-sensitive adhesive layer is transferred to the agent. Therefore, it is important to control the balance of tack and crosslinking amount, and in the adhesive film according to an embodiment of the present invention, the measured value of tack 　 adhesive force is 40 gf or more, and isocyanate-based curing agent 0.5- with respect to the total content of the composition It can have excellent tack adhesion and crosslinking properties at the same time by including 3.0% by weight.

In addition, when the prepared adhesive film is cut into a sheet or cell due to excellent tack adhesion and crosslinking properties, the occurrence of burrs or steaming on the adhesive surface can be significantly reduced.

Optionally, the protective film may further include a release film layer 130 on the pressure-sensitive adhesive layer 120 . The release film layer 130 may have a structure in which a release substrate and a release layer are sequentially stacked. For example, the release film layer 130 is coated with a release agent such as a silicone resin on a release substrate such as PET. It may be formed by

In an exemplary embodiment, the protective film 100 may have a peel electrification voltage of 0.3 kv or less. Accordingly, the protective film can prevent damage to the panel positioned above or below due to static electricity generated when the protective film is peeled off.

In an exemplary embodiment, the protective film 100 may have a surface resistance of 10 ⁹ Ω or less. If the surface resistance is more than 10 ⁹ Ω, the static electricity may be 1Kv or more when peeling the adhesive film.

How to make a protective film

Another embodiment of the present invention comprises the steps of preparing a base film; and forming a pressure-sensitive adhesive layer including the pressure-sensitive adhesive composition according to an embodiment of the present invention on the base film;

The base film is the same as described above, and the step of forming the pressure-sensitive adhesive on the base film is specifically, coating the above-described pressure-sensitive adhesive composition on one surface of the base film, and drying it to form a pressure-sensitive adhesive layer. there is.

In an exemplary embodiment, the application of the pressure-sensitive adhesive composition may be applied on a base film by a coating method generally used in the art, but is not particularly limited, for example, a die coater, a nip coater, a gravure roll coater and A comma coater or the like can be used. After application, the pressure-sensitive adhesive composition may be dried at, for example, 50 to 110° C. to form a pressure-sensitive adhesive layer.

In an exemplary embodiment, the process speed of forming the pressure-sensitive adhesive layer may be 5 m/min or less. This is for the stability of the initial curing, and when the speed is more than 5 m/min, the initial curing is not sufficiently performed, and it may be difficult to maintain a thickness of 100 μm or more of the pressure-sensitive adhesive layer.

In an exemplary embodiment, before forming the pressure-sensitive adhesive layer, forming a primer layer including a urethane-based resin on the base film; may further include.

Optionally, the method for manufacturing the protective film may further include forming a release film layer on the pressure-sensitive adhesive layer. The release film layer may be manufactured to have a structure in which a release substrate and a release layer are sequentially stacked. For example, the release film layer may be formed by applying a release agent such as a silicone resin on a release substrate such as PET. After that, it is possible to prevent foreign substances and poor handling by laminating a silicone-coated release film on the adhesive-coated surface.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example

[Example 1] Preparation of pressure-sensitive adhesive composition

Based on the total weight of the pressure-sensitive adhesive composition, 45% by weight of butyl (meth)acrylate as an acrylic monomer, 2.5% by weight of a polyester oligomer containing a carboxyl group and an unsaturated bond as an unsaturated monomer containing a carboxyl group and a hydroxyl group, hexamethylene diisocyanate as an isocyanate curing agent (HDI) 0.5% by weight, and bis(trifluoromethanesulfonyl)imilithium (LiN(CF ₃ SO ₂ ) ₂ ) 2.0% by weight as an ionic charging agent was mixed to prepare a pressure-sensitive adhesive composition.

[Example 2] Preparation of protective film

The pressure-sensitive adhesive composition of Example 1 was applied on the base film using a comma. By adjusting the gap of the comma knife, it was applied evenly with a thickness of 66um wet (based on solid content of 30%). After the pressure-sensitive adhesive composition was applied, it was dried at 120° C. for 0.03 hours to prepare a 20 μm adhesive layer protective film.

2 and 3 show the phenomenon of precipitation of unreacted or electrified components having Tm at room temperature when the prepared protective film is attached to the adherend, and the precipitated portion is analyzed by SEM imaging (FIG. 2) and EDS (FIG. 3) It was confirmed that the major agent (component D) was detected.

Through this, i) first, the phenomenon of transfer to the adherend when the content of the charge agent is added in excess inside the adhesive, and ii) second, when the crystallization temperature of the charge agent in the adhesive is near room temperature (25 degrees), it crystallizes and adheres The phenomenon causing metastasis was confirmed.

[Experimental Example 1] Protection film evaluation criteria setting

Evaluation was carried out on the basis of whether the pressure-sensitive adhesive layer was soft or hard in the prepared protective film. This criterion is interpreted as judging by the tack and the Tg of the pressure-sensitive adhesive layer.

That is, to make it a little softer, select a formulation with a low Tg or add tackifier to make it softer. On the other hand, to make it hard, the opposite is done. However, when making an excessively soft pressure-sensitive adhesive layer (PSA), the PSA residue is attached to the cutting section during cutting and affects the appearance. On the other hand, if it is too hard, residual PSA material is generated after cutting, which also affects the appearance. And, there is a problem that it does not adhere well to the adherend with a large Ra value. That is, there is a need to adjust Softness and Hardness.

Accordingly, according to the tack and pencil hardness of the PSA, two levels of Softness (S) and two levels of Hardness (H) were set as follows.

1) Softness

1-1) Softness Stage 1: S1

1-2) Softness Level 2: S2

2) Hardness

2-1) Hardness Level 1: H1,

2-2) Hardness Level 2 H2

3) Softness & Hardness (composite hardness)

3-1) Softness Level 1 & Hardness Level 1 S1H1

3-2) Softness Level 2 & Hardness Level 1 S2H1

3-3) Softness Level 1 & Hardness Level 2 S1H2

3-4) Softness Level 2 & Hardness Level 2 S2H2

S1 S2 H1 H2 S1H1 S2H1 S1H2 S2H2 Tack(gf) 20-60 60-100 10-20 0-10 20-40 40-70 10-20 10-30 Burr(ea) 0-10 0 10 to 50 0 0-20 0 0-10 0-10 Steamed (OK/NG) OK NG OK OK NG OK OK OK Ra 0.5um~2um (Adhesiveness OK/NG) NG OK NG NG NG OK NG NG Separation voltage (Kv) 0.43 0.28 0.89 1.32 0.48 0.19 0.56 0.39

Therefore, when proceeding to step S2H1, adhesion is good even at Ra 0.5um to 2um, and fairness is secured because there is no occurrence of burrs and steaming during cutting. Additionally, it was confirmed that the delamination voltage was also 0.19Kv, which met the development goal.

[Experimental Example 2] Protective film adhesion test

In order to select the adherend, the surface roughness of the adherend was measured as shown in FIGS. 4A and 4B. Specifically, FIGS. 4A and 4B are photographs of the roughness of the surface using 2D and 3D, respectively, where FIG. 4A is a diagram of 4b that the roughness (Ra) of the surface was measured using 2D, and 3D of the surface was taken accordingly. . Through this, the adhesiveness of the protective film was tested by selecting an adherend with a high roughness with a surface roughness of 0.6 μm. Adhesion was evaluated by attaching a protective film prepared to an adherend having a Ra of 0.6 μm as follows.

As a result, it was well laminated in FIG. 5A, but it was confirmed that microbubbles were generated during lamination of a film having a large Ra value in FIG. 5B, which is a phenomenon that occurs because adhesion is not performed due to insufficient softness of the adhesive layer. Therefore, in order to strengthen the softness and make the S2H1 stage, the isocyanate curing agent was processed at 0.5% by weight to develop and design so that adhesion can be obtained.

[Experimental Example 3] Peeling electrification voltage test according to the content of the charge agent

A pressure-sensitive adhesive composition containing 1 to 3% by weight of an isocyanate-based curing agent was prepared, and peel electrification voltage was evaluated according to the content of the charging agent. The protective film was laminated on a melamine plate (Size: A4) and after 30 minutes had elapsed, it was peeled off at a speed of 30 m/min MAX. ). The results are shown in Table 2 below.

Electrostatic content <wt%> Stripping voltage <Kv> note Primary Secondary tertiary 4th 0.5 -0.89 -0.92 -0.99 -0.89 Stripping voltage NG One -0.74 -0.64 -0.63 -0.66 Stripping voltage NG 1.5 -0.43 -0.45 -0.48 -0.49 Stripping voltage NG 2.0 -0.21 -0.23 -0.19 -0.22 2.5 -0.23 -0.33 -0.37 -0.27 precipitation 3.0 -0.22 -0.23 -0.38 -0.32 precipitation 5.0 or higher -0.34 -0.37 -0.41 -0.34 precipitation

[ Experimental example 4] According to the content of isocyanate-based curing agent stripping voltage and hardness test

From the above-described Experimental Example 1, when 2.0 wt% or more of the charge agent was added, it was confirmed that the charge agent component was not only precipitated, but also the peel electrification voltage was not significantly lowered. From this, assuming that the content of the antistatic agent is 2.0 wt% based on the total weight of the pressure-sensitive adhesive composition, the peel electrification voltage was tested by varying the content of the isocyanate-based curing agent when the content of the antistatic agent was 2.0 wt%. The measurement of the peel voltage was the same as in Experimental Example 1.

In addition, a hardness test was performed by measuring the occurrence of burrs and steaming. The occurrence of burrs and steaming was evaluated by measuring the number of burrs and steaming occurrence in 3 lines at 300mm length with a pencil test (8H Pensil, 700g load, Speed 2m/min). The peel electrification voltage and hardness test results are shown in Table 3 below.

Hardener content Stripping voltage <Kv> Burr
<ea> steamed Tack
<gf> step adherence
<OK/NG> <% by weight> Primary Secondary tertiary 4th 0.50% 0.19 0.18 0.21 0.19 0 OK 65 S2H1 OK 1.00% 0.27 0.29 0.27 0.28 15 OK 40 S1H1 NG 1.50% 0.39 0.37 0.42 0.36 35 OK 19 H1 NG 2.00% 0.44 0.56 0.55 0.63 47 OK 10 H1 NG 2.50% 0.89 1.23 0.92 1.12 0 OK 5 H2 NG 3.00% 1.56 1.73 1.49 1.53 0 OK 3 H2 NG

[Experimental Example 5] Surface resistance test according to the content of isocyanate-based curing agent

The surface resistance test was performed by measuring the average value after measuring the surface resistance 9 times under the conditions of 100V and 5sec using a measuring device METRISO-2000. The results are shown in Table 4 below.

Hardener content Surface resistance <Ω> <% by weight> Primary Secondary tertiary 4th 0.50% 8.73*10 ⁸ 5.72*10 ⁸ 6.80*10 ⁸ 4.98*10 ⁸ 1.00% 1.11*10 ⁹ 2.32*10 ⁹ 3.13*10 ⁹ 2.22*10 ⁹ 1.50% 4.25*10 ⁹ 5.24*10 ⁹ 4.92*10 ⁹ 5.24*10 ⁹ 2.00% 8.88*10 ⁹ 6.32*10 ⁹ 7.09*10 ⁹ 8.18*10 ⁹ 2.50% 2.12*10 ¹⁰ 1.48*10 ¹⁰ 9.32*10 ⁹ 2.87*10 ¹⁰ 3.00% 4.43*10 ¹⁰ 5.01*10 ¹⁰ 4.29*10 ¹⁰ 2.91*10 ¹⁰

From the experimental results, when the isocyanate-based curing agent was added in an amount of 2.0 wt % or more, the fluidity of cations and anions of the charge agent in the pressure-sensitive adhesive layer was lowered, and the peel electrification voltage and surface resistance were increased, and it was confirmed that the effect of the charge agent could not be obtained. In addition, when the curing agent was added in an amount of 0.5 wt % or less, it was confirmed that the curing degree and cohesive force of the PSA were low, so that the transfer occurred in the adherend and thus the function of the adhesive tape could not be exhibited.

Accordingly, the pressure-sensitive adhesive composition has a pressure-sensitive adhesive layer in which the adhesion is ensured not only in S2H1 stage cutting fairness and ultra-low peel electrification voltage, but also in Ra value of 0.5um to 2um in about 0.5% by weight of the isocyanate curing agent and about 2.0% by weight of the ionic charge agent. film can be made.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the protection scope of the present invention as long as they are apparent to those of ordinary skill in the art.

Claims (15)

Based on the total content of the composition, 30-50% by weight of an acrylic monomer, 0.5-10% by weight of an unsaturated monomer containing a carboxyl group and a hydroxyl group, 0.5-1.0% by weight of an isocyanate-based curing agent, and 0.1-2.0% by weight of an ionic charge A pressure-sensitive adhesive composition comprising A pressure-sensitive adhesive layer comprising;
The ionic charge agent is lithium iodide (LiI), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), lithium hexafluoroalsenate (LiAsF ₆ ), lithium tetrafluoroborate (LiBF) ₄ ), lithium hexafluorophosphate (LiPF ₆ ), sodium hexafluorophosphate (NaPF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), bis(trifluoromethanesulfonyl)imilithium (LiN) (CF ₃ SO ₂ ) ₂ ), tris(trifluoromethanesulfonyl)methlithium (LiC(CF ₃ SO ₂ ) ₃ ), bis(fluorosulfonyl)imide potassium (KaN(FSO ₂ ) ₂ ) , bis(fluorosulfonyl)imide sodium (NaN(FSO ₂ ) ₂ ) and bis(fluorosulfonyl)imilithium (LiN(FSO ₂ ) ₂ ) protection comprising at least one selected from the group consisting of As a film, the protective film has a surface resistance of 10 ⁹ Ω or less measured at 100 V, 5 sec conditions using a measuring device METRISO-2000, and tack adhesive force measured using a probe tack device at 25 ° C. A protective film with a measured value of 40 gf or higher. delete The method of claim 1,
0.5-1.5 wt% of an ionic charge based on the total content of the composition; characterized in that it comprises a, protective film. According to claim 1,
The isocyanate-based curing agent comprises at least one curing agent selected from the group consisting of torylene diisocyanate, xylene diisocyanate, and hexamethylene diisocyanate. film. delete delete The method of claim 1,
The protective film further includes a base film, wherein the base film includes polyethyleneterephthalate (PET), polybutyleneterephthalate (PBT), polyethylenenaphthalate (PEN), and polybutylenenaphthalate ( A protective film comprising at least one selected from the group consisting of polybutylenenaphthalate: PBN), polyethylene (PE), polypropylene (PP), and polyimide. delete The method of claim 1,
The protective film, characterized in that it further comprises a release film layer on the pressure-sensitive adhesive layer. delete According to claim 1,
The protective film is laminated on a melamine plate and after 30 minutes has elapsed, the value measured after peeling at a speed of 30 m/min MAX is characterized in that it has a peeling electrification voltage of 0.3 kv or less, the protective film. delete preparing a base film; and
A method for producing a protective film, comprising a; forming a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition of any one of claims 1 and 3 to 4 on the base film. 14. The method of claim 13,
The process speed of the step of forming the pressure-sensitive adhesive layer is a method for producing a protective film, characterized in that 5 m / min or less. 14. The method of claim 13,
Before forming the pressure-sensitive adhesive layer, forming a primer layer comprising a urethane-based resin on the base film; protective film manufacturing method further comprising a.

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