KR101719750B1 - Embossed adhesive sheet and preparation method thereof - Google Patents

Abstract

The present invention relates to an adhesive sheet which can be applied as double-sided adhesive tapes, and to a production method thereof. To this end, the adhesive sheet includes: a base material film; and an embossed adhesive layer formed at least one side of the base material film. When the embossed adhesive layer uses an embossed adhesive sheet of which fine structures including an adhesive resin have regular patterns, deaeration can be effectively done when attaching the embossed adhesive layer since the embossed adhesive layer does not have a base, thereby enhancing adhesiveness and becoming thinner.

Description

EMBOSSED ADHESIVE SHEET AND PREPARATION METHOD THEREOF [0002]

The present invention relates to a pressure-sensitive adhesive sheet which can be used as a double-sided pressure-sensitive adhesive tape, and a method for producing the same. More specifically, the present invention relates to a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer patterned in embossed form and excellent in degassing and adhesion, and a method for producing the pressure-sensitive adhesive sheet.

In recent products such as a liquid crystal display (LCD) and an organic light emitting diode (OLED) display, a double-sided pressure-sensitive adhesive sheet is often used for fixing internal parts and the like. An adhesive sheet having an adhesive layer formed on both surfaces of a base film is used have.

When the double-sided pressure-sensitive adhesive sheet is applied to a product, there is a problem that air bubbles are trapped in the pressure-sensitive adhesive layer. Such bubbles deteriorate the adhesive force and particularly cause deterioration of the image quality of the display. To this end, the double-sided pressure-sensitive adhesive sheet is attached to the product and then rubbed while rubbing the pressure-sensitive adhesive sheet. However, when a conventional pressure-sensitive adhesive sheet is used, it is not easy to remove bubbles trapped in the pressure-sensitive adhesive layer.

Thus, a method has recently been proposed in which an embossing pattern having fine convex portions and concave portions is formed on the adhesive layer to attach the double-sided pressure-sensitive adhesive sheet to a product and facilitate the evacuation through the concave portions when pressed. In the embossed adhesive sheet, the embossed adhesive sheet spreads in a plane while pressing the convex portion through the pressing after the attachment to the product, and at the same time, the concave portion is deaerated through the recess in the process of gradually narrowing the concave portion. Finally, when the pressurization is completed, a flat adhesive layer without bubbles or embosses is formed.

As a method of forming such embossed patterns, there is known a technique of using an embossed release paper. Referring to FIG. 7, in the conventional technique, the release film on which the emboss pattern is formed is wound on a roll 345 and prepared. First, the adhesive resin 125 is uniformly coated on the base film by a general coating roll 320 while the base film is being unwound from the base film roll 310. Thereafter, the pressure-sensitive adhesive resin coated on the surface is cured while transferring the base film to form an adhesive layer. Thereafter, the base film and the adhesive layer are laminated with the embossed film to be wound while being passed between the pressing roll 350 and the rolls 345 of the embossed film, and finally wound up on the winding roll 360. In this process, the emboss pattern of the embossed film is transferred to the adhesive layer to produce an embossed adhesive sheet.

8A to 8C, the adhesive coating layer 220 'is formed first, and then the surface of the adhesive coating layer 220' is pressed by the embossing film 250 to form an embossed film The base surface 223 must be present under the convex portion 221 and the concave portion 222 of the emboss pattern. Therefore, in the conventional embossed adhesive sheet, the entire film thickness must be increased by the thickness of the base surface 223, so that it is not easy to realize the thickness of the thin film. Since the adhesive resin is present in the concave portion 222 as well as the convex portion 221 of the embossed pattern by the base surface 223, There is a problem that the air passage in the recessed portion 222 is partially blocked, and therefore, it is not easy to degas. In addition, since the pattern is transferred after the curing of the pressure-sensitive adhesive resin, the viscosity becomes so large that the shape of the concave portion 222 of the pressure-sensitive adhesive layer is not formed as precisely as the emboss pattern 255 of the release film, The base surface 223 'becomes thicker and the shape of the convex portion 221 and the concave portion 222 becomes more unclear. In addition, the method according to the above-described prior art is complicated in the process itself, so that not only the required cost is high but also the thickness and physical properties of the used release paper affect the embossing, so that it is difficult to obtain the desired embossing.

The inventors of the present invention have found that an embossed adhesive sheet excellent in degassing property and adhesive property can be produced by a simple method, and the present invention has been completed.

Korean Patent No. 1381442 (3M Innovative Properties Company)

Accordingly, an object of the present invention is to provide an embossed adhesive sheet excellent in degassing and adhesion, and a method of effectively and simply producing the embossed sheet.

According to the above object, the present invention provides an embossed adhesive sheet comprising a base film and an embossed adhesive layer formed on at least one side of the base film, wherein the embossed adhesive layer comprises (i) A plurality of microstructures containing a resin, and (ii) regions in which no adhesive resin is applied between the microstructures.

According to another aspect of the present invention, there is provided a method for manufacturing a pressure sensitive adhesive sheet, comprising the steps of feeding a pressure sensitive adhesive resin composition to an engraved portion of an embossed pattern of a roll while moving a base film such that the base film is passed through a roll having an emboss pattern, Comprising a base film and a plurality of microstructures formed on at least one side of the base film, wherein the microstructures are formed on a base film in the form of a plurality of microstructures having the same height, A method for producing an embossed adhesive sheet comprising an adhesive layer is provided.

Since the embossed adhesive sheet does not have a base surface in the embossed layer of the embossed pattern, it can be effectively deaerated when adhered to the adherend, and can be made into a thinner film having an excellent adhesive strength. Such an embossed adhesive sheet can be easily produced by directly forming a pressure-sensitive adhesive resin composition on a base film in the form of a patterned microstructure through a roll having a pattern on its surface. Therefore, the embossed adhesive sheet can be variously used as a constituent interlaminar adhesive tape in a field where bubble generation such as an OLED display should be suppressed.

1A and 1B illustrate examples of cross-sections of an embossed adhesive sheet according to the present invention.
Fig. 2 shows examples of the horizontal cross-sectional shape of the pattern of the embossed adhesive layer.
3 shows a photograph of the embossed adhesive layer and its enlarged image.
4A and 4B are photographs at the time of attaching the embossed adhesive sheet according to an example of the present invention, and photographs after bubble removal through pressurization.
Figs. 5A and 5B are photographs at the time of attaching the embossed adhesive sheet according to the comparative example and after removal of bubbles through pressurization.
6A and 6B show examples of a method of producing an embossed adhesive sheet by thermal curing according to the present invention.
7 shows a method of manufacturing an embossed adhesive sheet according to the prior art.
8A to 8C show cross-sectional shapes at the time of manufacturing the embossed adhesive sheet according to the prior art.

Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings. In order to facilitate understanding, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

1A, an embossed adhesive sheet 100 according to the present invention includes a base film 110 and an embossed adhesive layer 120 formed on at least one surface of the base film 110, (I) a plurality of microstructures 121, which are discretely spaced apart from each other, but which have the same height and contain an adhesive resin, and (ii) areas where the adhesive resin is not applied between the microstructures 122).

Hereinafter, each layer will be described in detail.

The embossed adhesive layer is a patterned layer which provides excellent adhesion through microstructures 121 containing a pressure sensitive adhesive resin and provides an uncoated area 122 without microstructures 121, Provides excellent degassing through the area.

Referring to FIG. 1A, the embossed adhesive layer 120 includes microstructures 121 that are discontinuously spaced from each other on a vertical cross-sectional structure and have the same height.

The microstructures 121 contain a pressure-sensitive adhesive resin. Specifically, the microstructures 121 are made of an adhesive resin. Accordingly, the microstructures 121 can exhibit adhesion.

In contrast, the embossed adhesive layer 120 includes uncoated regions 122 of the adhesive resin between the microstructures 121 on the vertical cross-sectional structure. That is, the uncoated areas 122 are areas on the base film where the adhesive resin is not applied. Accordingly, no material is present in the uncoated areas 122, and the surface of the base film 110 may be exposed through the uncoated areas 122. The non-applied areas 122 may serve as air passages when attaching the embossed adhesive sheet to the adherend. On the other hand, according to the conventional embossed adhesive sheet, referring to FIG. 8C, since the bases 223 'of the pressure-sensitive adhesive resin are also present in the concave portions 222, the performance as an air passage when adhering to the adherend may be deteriorated.

The spacing of the microstructures, that is, the depth d of the non-coated region 122 is equal to the height of the microstructures 121, and is equal to the thickness t of the embossed adhesive layer 120. 8C, the depth of the concave portions 222 is the same as the height of the convex portions 221. However, due to the presence of the base surface 223 ', the embossed adhesive layer 220 can be easily formed, .

The microstructures 121 may have a height of 1 to 20 탆, preferably 2 to 10 탆, and more preferably 2 to 8 탆. Within the above-mentioned preferable range, the pattern formation can be facilitated and the adhesive force can be further improved.

The embossed adhesive layer has a regular pattern of microstructures 121 and uncoated areas 122 when viewed in a horizontal cross-sectional shape.

Fig. 2 shows examples of the horizontal cross-sectional shape of the pattern of the embossed adhesive layer. In FIG. 2, the white region represents the fine structures 121 and the black region represents the non-applied regions 122. The microstructures 121 may have a horizontal cross sectional shape of a regular pattern of polygonal (e.g., rhombic, rectangular, etc.), circular, elliptical, stripe, or a combination thereof.

The microstructures may have a length or diameter of from 1.0 to 5.0 mm in the horizontal cross-sectional shape. Specifically, when the horizontal cross-sectional shape of the microstructures 121 is polygonal, the length L of one side may be 0.1 to 10 mm, and more preferably 1.0 to 5.0 mm. In addition, the diameter L of the microstructures 121 may be in the range of 0.1 to 10 mm, more preferably 1.0 to 5.0 mm. When the amount is within the above-mentioned preferable range, the pattern can be easily formed and the bubbles can be removed more effectively.

The spacing of the microstructures, that is, the width of the uncoated region 122 may be 0.01 to 0.5 mm, and more preferably 0.1 to 0.3 mm. Within the above-mentioned preferable range, the bubbles can be removed more effectively, and the pattern formation is advantageous in achieving precision and adhesion.

3 shows a photograph of the embossed adhesive layer and its enlarged image. 3, the adhesive layer having a regular emboss pattern can be identified.

The embossed adhesive sheet may further include an additional functional layer on the other side of the base film 110 and the embossed adhesive layer 120. Referring to FIG. 1B, the embossed adhesive sheet 100 'may further include a printed layer 140 and / or a non-patterned regular adhesive layer 130 formed on the other side of the base film 110. In addition, the release films 151 and 152 may be further provided on at least one of both outer surfaces.

The base film 110 may be a transparent film, for example, a transparent polymer film. The base film may include a polymer resin selected from the group consisting of polyolefin, polystyrene, polycarbonate, polyester, cellulose, acrylic, polyvinyl chloride, and mixtures thereof. Specifically, the base film is selected from the group consisting of polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, triacetyl cellulose, acrylic, polyvinyl chloride and mixtures thereof And may include a polymer resin. In addition, the base film may be uniaxially or biaxially stretched, if necessary, in order to enhance mechanical strength or optical function. The thickness of the base film may be selected depending on the material, but may be 1 탆 to 100 탆, and preferably 3 탆 to 50 탆.

The non-patterned general adhesive layer 130 may include a polymer resin that is typically used in an adhesive layer, and may include, for example, an acrylic resin. Preferably, the general adhesive layer may include a thermosetting polymer resin and / or a UV curable polymer resin. The general adhesive layer may have a thickness of 1 탆 to 50 탆, more specifically, 2 탆 to 20 탆.

The release films 151 and 152 may include a commonly used release material such as silicone. The release film may have a thickness ranging from 10 to 100 mu m.

The printing layer 140 refers to a layer on which a color, a pattern, a pattern or the like is printed or deposited for a decoration function. The printing layer may be formed by printing or vapor deposition. Alternatively, a colored PET film may be used instead of the above printing or vapor deposition.

In the embossed adhesive sheet, the adhesive resin is not present in the uncoated areas of the embossed adhesive layer and there is no underlying adhesive surface as in the prior art, so that the surface of the base film is exposed, and therefore, .

4A and 4B are photographs at the time of attaching the embossed adhesive sheet according to an example of the present invention, and photographs after air bubbles are removed through pressurization. As shown in FIGS. 4A and 4B, it can be seen that the bubbles which were collected at the time of initial attachment were effectively removed through the pressurization.

On the other hand, Figs. 5A and 5B are photographs at the time of attaching the embossed adhesive sheet according to the comparative example and after removal of bubbles through pressurization. As a comparative example, in the case of using an embossed adhesive sheet in which the basesurface 223 'of the pressure-sensitive adhesive resin is present in the concave portions 222 of the embossed pattern as shown in FIG. 8C, the degassing effect is lowered, It can be seen that the air bubbles collected in the air bubbles are not completely removed even after they are pressurized.

The embossed adhesive sheet may have an adhesive strength of 100 to 2,000 gf / in, more preferably 300 to 1,000 gf / in. When the adhesive force is within the above-described preferable range, there is an advantage of adhesion and easy reworkability.

Further, since the embossed adhesive sheet does not have a base adhesive surface in the embossed adhesive layer, it is easier to realize a thin film thickness. For example, the embossed adhesive sheet may have a total thickness of 1 to 50 μm, 5 to 50 μm, 3 to 30 μm, or 5 to 30 μm.

The embossed adhesive sheet is obtained by supplying a pressure sensitive adhesive resin composition to an engraved portion of an embossed pattern of the roll while moving the base film such that the base film is passed through a roll having an embossed pattern so that the pressure sensitive adhesive resin composition is discretely spaced apart from each other And then curing the microstructures. The present invention also relates to a method of manufacturing a microstructure, comprising the steps of: forming a microstructure on a base film;

The formation of the pressure-sensitive adhesive resin composition on the base film using the roll having the emboss pattern may be a gravure roll coating.

The method of feeding the adhesive resin composition to the engraved portion of the emboss pattern of the roll includes (A) feeding the embossing pattern roll by partially immersing the embossing pattern roll in the adhesive resin composition and rotating it, and (B) A pressure-sensitive adhesive resin composition may be directly supplied to the engraved portion of the embossing pattern roll.

6A, according to an example (method A) of the method for manufacturing the embossed adhesive sheet, the roll 330 having the embossed pattern is immersed in the pressure-sensitive adhesive resin composition 125, The pressure sensitive adhesive resin composition may be supplied in the form of an emboss pattern formed on the base film together with the rotation of the roll 330 in the form of a microstructure. Thereafter, the microstructures are thermoset (510) to obtain a final embossed adhesive layer.

6B, an apparatus 126 for supplying a pressure-sensitive adhesive resin composition is prepared according to another embodiment (Method B) of the method for producing the embossed adhesive sheet, and the embossing pattern roll 330 ), The embossing pattern roll 330 is rotated to form the pressure-sensitive adhesive resin composition in the form of a microstructure on the base film, followed by thermosetting (510) to obtain an embossed adhesive layer .

After the curing, a step of laminating a release film on the embossed adhesive layer may be further included.

The roll having the embossed pattern may have a reversed phase pattern on the surface of the microstructures to be formed on the base film. That is, the pattern provided on the surface of the roll having the embossed pattern is an emboss pattern composed of embossed portions and engraved portions, and the engraved portions may be formed in a shape of a rhombus, a rectangle, a circle, an ellipse, a stripe, Which corresponds to the shape of the microstructures to be formed on the base film. For example, the engraved portion may have a length or diameter of 0.1 to 10 mm on one side, a depth of 1 to 20 탆, and a width of the embossed portion may be 0.01 to 0.5 mm.

The microstructure of the embossed adhesive layer is prepared from a pressure-sensitive adhesive resin. Specifically, the microstructure of the embossed adhesive layer is prepared by drying and curing a pressure-sensitive adhesive resin composition comprising a pressure-sensitive adhesive resin, a curing agent, a solvent and other additives.

6A, the pressure-sensitive adhesive resin composition 125 is filled in the concave portion of the pattern formed on the surface of the emboss patterned roll 330, and is rotated together with the roll 330, Coated on one side of the film in the form of a pattern, then dried and cured while being transported at a constant speed together with the base film to form an embossed adhesive layer.

In such a series of processes, the pressure-sensitive adhesive resin is required to (i) be easily and tightly filled in the engraved portion of the pattern formed on the surface of the roll, (ii) To be easily and precisely applied in the form of a pattern on one side of the film, and (iv) to maintain the pattern shape (i.e., microstructure shape) upon transportation with the base film.

Thus, in the series of steps of the above-described manufacturing method, a process requiring flowability of the pressure-sensitive adhesive resin composition 125 and a process requiring viscosity are mixed.

Therefore, it is important that the pressure-sensitive adhesive resin contained in the pressure-sensitive adhesive resin composition has thixotropy. The thixotropy means a property that the viscoelasticity of the polymer resin changes due to an external force. According to such characteristics, the polymeric resin is disentangled to lower its viscosity under high shear force such as mixing or application, while when the external force is removed, it returns to the entanglement form, can do. Therefore, the pressure-sensitive adhesive resin having thixotropic property can maintain the form of the coating film because the apparent viscosity is lowered at the time of coating and easily applied, but the viscosity is restored after the application and does not flow.

In order to impart thixotropy to the pressure-sensitive adhesive resin, it is preferable that the molecular weight and the acid value of the pressure-sensitive adhesive resin are controlled. As the molecular weight and the acid value of the pressure-sensitive adhesive resin are lower, the flowability is increased, so that the coating can be easily performed and the coating can be uniform, while the coated pattern shape (i.e., microstructure shape) can not be maintained and the pattern accuracy can be lowered. On the other hand, the viscosity of the pressure-sensitive adhesive resin increases as the molecular weight and the acid value become higher, so that the coating can not be easily performed because the coating can not be uniform, while the coated pattern shape can be maintained well and the pattern precision can be enhanced.

The pressure-sensitive adhesive resin may have a weight average molecular weight (Mw) of 500,000 to 1,000,000 g / mol. When the molecular weight of the pressure-sensitive adhesive resin is within the above-mentioned range, flowability and viscosity are balanced and the thixotropy is improved, which can be more advantageous for precise pattern formation and uniform coating. The weight average molecular weight of the pressure-sensitive adhesive resin may more preferably be 600,000 to 700,000 g / mol.

The pressure-sensitive adhesive resin may have an acid value of 8 to 12. When the acid value of the pressure-sensitive adhesive resin is within the above range, flowability and viscosity are balanced and the thixotropy is improved, which can be more advantageous for precise pattern formation and uniform coating. The acid value of the pressure-sensitive adhesive resin may be more preferably 9 to 11.

The pressure-sensitive adhesive resin may be a thermosetting resin or a UV-curable resin. Alternatively, the pressure sensitive adhesive resin may be a resin having both a thermosetting property and a UV setting property.

The pressure-sensitive adhesive resin may include an acrylic resin. The pressure sensitive adhesive resin may be pressure sensitive adhesive (PSA) acrylic resin.

For example, the acrylic resin is a resin in which one or more acrylic monomers are polymerized. The acrylic resin may be a resin obtained by polymerizing a combination of at least one of an acrylic monomer and a carboxyl group-containing unsaturated monomer. Specific examples of the acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, isobutyl (meth) acrylate, ) Acrylate, cyclohexyl (meth) acrylate, ethylhexyl (meth) acrylate, tetrahydroperfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, 2- (Meth) acrylate, methyl? -Hydroxymethylacrylate, ethyl? -Hydroxymethylacrylate (meth) acrylate, 2-hydroxy-3-chloropropyl (Meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethoxydiethylene glycol (Meth) acrylate, methoxytripropylene glycol (meth) acrylate, poly (ethylene glycol) methyl ether (meth) acrylate, tetrafluoropropyl (meth) acrylate, (Meth) acrylate, hexafluoroisopropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, isobonyl (Meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate and dicyclopentenyloxyethyl (meth) acrylate, and mixtures thereof.

Specific examples of the carboxyl group-containing unsaturated monomer include methyl (meth) acrylate, butyl (meth) acrylate, and mixtures thereof. Specific examples of the carboxyl group-containing unsaturated monomer include acrylic acid, methacrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid , Acrylic acid dimer, itaconic acid, maleic acid, maleic anhydride, and mixtures thereof, and preferably methacrylic acid, acrylic acid, and mixtures thereof.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted that the following embodiments are illustrative of the present invention and the scope of the present invention is not limited thereto.

Example 1: Production of pressure-sensitive adhesive sheet for each pattern size

A pattern of rhombic lattice as shown in Fig. 2 (a) is formed on a PET base film by using an acrylic copolymerizing pressure-sensitive adhesive resin (DS-8700), and the length and height of one side of the microstructure to which the pressure- The spacing between the microstructures (the width of the area where no adhesive resin was applied) was adjusted to the dimensions shown in Table 1 to form a pattern. As a result, a total of seven embossed adhesive sheets having different pattern dimensions were produced.

Test Example 1: Evaluation of pressure-sensitive adhesive sheet for each pattern size

The following items were evaluated for each of the embossed adhesive sheets prepared in Example 1 and summarized in Table 1 below.

(1) Pattern formation:

◎: The shape and boundary of the pattern are clear, the adhesive is 100% filled in the pattern,

○: The shape and boundary of the pattern are relatively clear, the adhesive inside the pattern is filled by 80% or more,

△: there is a part where the shape and boundary of the pattern are not clear,

X: No pattern formed.

(2) Bubble removal:

○: 100% of air bubbles were removed,

?: Bubbles were removed by 80% or more,

X: Bubbles are not removed well.

(3) Adhesion:

A sample was taken in a size of 25 mm x 250 mm and attached to a SUS304 steel plate of 50 mm x 150 mm. The sample was reciprocated twice with a 2 kg roller, pressed and left for 30 minutes. The test piece was bent at 180 degrees using a UTM and peeled off at a rate of 300 mm / min to measure the adhesive strength.

division Pattern dimension Evaluation results Microstructure
size Microstructures
Interspacing Microstructure
Height pattern
formation bubble
remove adhesiveness Pattern A 1.2 mm 0.2mm 3 탆 ○ ○ 400gf / in Pattern B 1.5mm 0.25 mm 5 탆 ◎ ○ 800gf / in Pattern C 2mm 0.25 mm 5 탆 ○ ○ 850gf / in Pattern D 0.5mm 0.2mm 1 탆 △ △ 100gf / in Pattern E 12mm 1mm 5 탆 ○ △ 500gf / in Pattern F 1.2 mm 0.2mm 2 탆 ○ ○ 350gf / in Pattern G 1.5mm 0.25 mm 8 탆 ◎ ○ 950gf / in

As shown in Table 1, the embossed sheets to which the patterns A, B, C, F and G having the pattern dimensions belonged to the preferred range of the present invention were excellent in pattern formation and bubble removing performance and had high adhesion.

On the other hand, the embossed adhesive sheets to which the patterns D and E having the pattern dimensions deviating from the preferred range of the present invention were somewhat poor in evaluation items of at least one of pattern formation, bubble removal and adhesive force.

Example 2: Production of pressure-sensitive adhesive sheet for each pressure-sensitive adhesive resin

Acrylic copolymerizable pressure-sensitive adhesive resins having molecular weights and acid values shown in Table 2 were prepared. Each of these pressure-sensitive adhesive resins was used to form an embossed adhesive layer having the pattern B on the PET base film in the process shown in Fig. 6A. As a result, a total of five embossed sheets produced using different pressure sensitive adhesive resins were produced.

Test Example 2: Evaluation of adhesive sheet for each adhesive resin

The following items were evaluated for each embossed adhesive sheet prepared in Example 2 and summarized in Table 2 below.

&Amp; cir &: The shape of the pattern is clear,

?: The shape of the pattern can be seen, but the coating thickness is uneven,

?: The shape of the pattern is visible, but the shape is uneven, the coating thickness is uneven,

X: Pattern is not formed.

division Adhesive resin Evaluation results Molecular weight (g / mol) Acid value Pattern formation Resin A 60 million 10 ◎ Resin B 65 million 11 ◎ Resin C 70 million 12 ○ Resin D 75 million 14 △ Resin E 300,000 6 X

As shown in Table 2, the embossed adhesive sheets to which the pressure-sensitive adhesive resins A, B, and C having the molecular weight and acid value of the pressure-sensitive adhesive resin within the preferred range of the present invention were applied had a clear pattern shape and a substantially uniform coating thickness.

On the other hand, the embossed adhesive sheets to which the pressure-sensitive adhesive resins D and E having the pattern dimensions deviating from the preferred range of the present invention were applied were uneven in shape and non-uniform in thickness even if no pattern was formed or a pattern was formed.

The embossed adhesive sheet can be used as a double-faced adhesive tape in various fields and products. In particular, it can be used for products requiring high transparency and degassing properties, such as double-faced pressure-sensitive adhesive sheets used for fixing internal parts in products such as liquid crystal displays (LCD) and organic light emitting diode (OLED) displays.

100, 100 ': embossed adhesive sheet according to the present invention,
110: substrate film, 120: embossed adhesive layer,
121: microstructure, 122: uncoated region,
125: pressure-sensitive adhesive resin composition, 126: pressure-sensitive adhesive resin supply device,
130 general adhesive layer, 140 printing layer,
151, 152: release film, 200: embossed adhesive sheet according to the prior art,
210: base film, 220: embossed adhesive layer,
220 ': adhesive coating layer, 221: convex portion,
222: concave portion, 223, 223 ': base surface,
250: embossed film, 255: embossed pattern of release film,
310: substrate film roll, 320: (non-patterned) coating roll,
330: roll having an emboss pattern, 340: release film roll,
345: Embossed film roll, 350: Pressure roll,
360: winding roll, 510: thermosetting,
L is the length or diameter of one side of the microstructure,
w: width of uncoated area, d: depth of uncoated area,
t: thickness of embossed adhesive layer.

Claims (12)

An embossed adhesive sheet comprising a base film and an embossed adhesive layer formed on at least one side of the base film,
The embossed adhesive layer
(i) a plurality of microstructures which are discretely spaced apart from each other but which have the same height and contain a pressure-sensitive adhesive resin, and
(ii) an embossed adhesive sheet comprising areas where the adhesive resin is not applied between the microstructures,
(PSA) acrylic resin having at least one of a thermosetting property and a UV setting property and having a weight average molecular weight of 600,000 to 700,000 g / mol and an acid value of 8 to 12,
Wherein the microstructures have a horizontal cross-sectional shape of a regular pattern of polygonal, circular, elliptical, stripe, or a combination thereof having a length or diameter of 1.0 to 5.0 mm and having a height of 2 to 10 탆, mm and spaced apart from each other at an interval of 1 mm.
The method according to claim 1,
Wherein the microstructures have a rhombic lattice-like regular pattern horizontal cross-sectional shape.
3. The method of claim 2,
Wherein the microstructures have a length of 1.0 to 5.0 mm in a horizontal cross-sectional shape and are spaced apart from each other by an interval of 0.1 to 0.3 mm.
The method of claim 3,
Wherein the microstructures have a height of 2 to 8 占 퐉.
The method according to claim 1,
Wherein the embossed adhesive sheet has an adhesive strength of 300 to 1,000 gf / in.
delete delete The method according to claim 1,
Wherein the embossed adhesive sheet has a total thickness of 5 to 50 占 퐉.
The pressure sensitive adhesive resin composition is fed to the engraved portion of the embossed pattern of the roll while moving the base film such that the base film is passed through the roll having the embossed pattern so that the pressure sensitive adhesive resin composition is discontinuously separated from each other by a plurality of microstructures And then curing the microstructures. The method of claim 1,
A method for producing an embossed adhesive sheet comprising a base film and an embossed adhesive layer composed of a plurality of microstructures formed on at least one side of the base film,
(PSA) acrylic resin having a weight average molecular weight of 600,000 to 700,000 g / mol and an acid value of 8 to 12, the pressure-sensitive adhesive resin composition having at least one of thermosetting property and UV-curable property,
Wherein the microstructures have a horizontal cross-sectional shape of a regular pattern of polygonal, circular, elliptical, stripe, or a combination thereof having a length or diameter of 1.0 to 5.0 mm and having a height of 2 to 10 탆, mm in the longitudinal direction of the embossed adhesive sheet.
10. The method of claim 9,
Wherein the formation of the pressure-sensitive adhesive resin composition on the base film using a roll having the embossed pattern is a gravure roll coating.
11. The method of claim 10,
The feeding of the embossing pattern of the pressure-sensitive adhesive resin composition to the engraved portion of the roll,
Wherein the adhesive layer is formed by rotating the roll having the embossed pattern partially immersed in the pressure-sensitive adhesive resin composition.
10. The method of claim 9,
Wherein the hardening of the microstructures is thermosetting.

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