KR101467532B1 - A Self-adhesive Protection Film having improved properties - Google Patents

Abstract

The present invention provides a self-adhesive protective film. The self-adhesive protective film of the present invention comprises: a support layer; And an adhesive layer formed on one or both surfaces of the support layer, the adhesive layer comprising a polystyrene elastomer and an ethylene vinyl alcohol copolymer. INDUSTRIAL APPLICABILITY According to the present invention, a self-adhesive protective film excellent in cuttability, adhesiveness and thermal stability is obtained by incorporating a polystyrene-based elastomer and an ethylene vinyl alcohol copolymer into an adhesive layer.

Description

[0001] The present invention relates to a self-adhesive protective film having improved performance,

The present invention relates to a self-adhesive protective film with improved performance, and more particularly, to a self-adhesive protective film having improved self-sticking protection with improved mechanical properties such as adhesiveness, heat resistance and cutability by including a polystyrene elastomer and an ethylene vinyl alcohol copolymer in a pressure- Lt; / RTI >

BACKGROUND ART An adhesive film or sheet has been conventionally used as a surface protecting film for protecting the surface of a product such as a synthetic resin plate, a veneer sheet and a metal plate from adherence, contamination and scarring of a lacquer or as a protective film for a surface of a window glass, And has been used as a surface protective film at the time of coating or solder dipping of a printed board. Further, it is possible to use a precise electronic component such as a liquid crystal display, a liquid crystal panel, a reflection plate, a retardation plate, a prism sheet, a light guide plate, a flat steel plate, a plasma display panel plate, and an organic phosphor thin film which are components of a plasma display device or an organic thin film EL device And is widely used as a surface protective film.

Recently, the demand for the development of high-performance, high-performance protective film that does not cause a problem of residue, which is a cause of defects, has been increasingly demanded by IT companies due to the complexity and miniaturization of parts for IT.

Conventional solvent type protective film manufacturing processes include a base film loading (releasing) process, a coating process of the prepared coating liquid, a drying process for removing residual solvent in the coating liquid, aging, And the like. The pressure-sensitive adhesive used in the solvent-type pressure-sensitive adhesive protective film is an acrylic type solvent, and a solvent is used for the coating. The solvent used is toluene xylene, butyl acetate or the like, which causes dizziness and headache . In addition, VOC (Volatile Organic Compound), which is harmful to the atmospheric environment, is emitted during the drying process.

Recently, a solvent-free self-adhesive protective film which does not use a solvent has been proposed as a technique for replacing the manufacturing process of such a solvent-type protective film. Such a solventless self-adhesive protective film of the non-solvent type has an advantage of being able to overcome such low recyclability while having a solvent-type protective film having low recyclability due to an adhesive applied on the surface thereof.

At present, due to the advantages of the self-adhesive protective film described above, the necessity and interest for development are increasing, but the level of domestic products is still short of the manufacturers of SMEs.

Generally, in order to impart a self-adhesive property, when a protective film is processed by a blowing method or a casting method, ethylene vinyl acetate or ethylene acrylic acid having self-adhesive property is co-extruded to a layer to be adhered to a substrate to perform multilayer processing do.

However, the conventional coextruded multilayer film using the vinyl acetate based adhesive layer has a disadvantage in that it is inferior to the conventional solvent type adhesive protective film in adhesion, heat resistance, and the like. In addition, defects are generated in the extrusion process of the film, and the defective product generation ratio is high, which limits the application to optical sheets requiring high quality.

The self-adhesive protective film must have good adhesion and should have a minimum change ratio in order to enhance the heat resistance. It should be easy to cut after bonding with the substrate, and there should be no material remaining on the substrate after peeling off the film.

Accordingly, there is a growing need for an environmentally friendly self-adhesive protective film that is excellent in mechanical properties such as adhesion and heat resistance, and is easy to manufacture.

Korean Patent Laid-Open No. 10-2012-0008703

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-adhesive protective film having improved mechanical properties by including a polystyrene elastomer and an ethylene vinyl alcohol copolymer in an adhesive layer.

In order to accomplish the above object, the present invention provides a self-

Supporting layer; And an adhesive layer formed on one or both surfaces of the support layer and including a polystyrene elastomer and an ethylene vinyl alcohol copolymer (EVOH).

In the adhesive layer, the polystyrene-based elastomer may be 40 to 70 wt% based on the total weight of the adhesive layer, and the ethylene-vinyl alcohol copolymer may be 10 to 30 wt%. The polystyrene- (ethylene / buthylene) -crystalline block copolymer (CEBC), hydrogenated styrene butadiene rubber (HSBR), styrene- (ethylene / buthylene) (Polystyrene-block-poly (ethylene-ethylene / propylene) -block polystyrene), SEEPS-OH (styrene-isobutylene-styrene triblock copolymer ) SEP (polystyrene-block-poly (ethylene / propylene), and SEPS (polystyrene-block-poly (ethylene / propylene) -block-polystyrene).

The adhesive layer may further include a tackifier resin, and the tackifier resin preferably has a weight average molecular weight of 900 to 1500 or less.

The adhesive layer may further include an adhesive force adjusting agent, and the adhesive strength adjusting agent is preferably contained in an amount of 15 to 50% by weight based on the total weight of the adhesive layer. The adhesion modifier is preferably an elastomer having a lower adhesiveness than the polystyrene elastomer. In one preferred embodiment, the elastomer having lower adhesiveness than the polystyrene elastomer is an ethylene-based, propylene-based, acrylonitrile-based, butadiene-based, , Isoprene-based, polyurethane-based, and silicone-based ones.

The supporting layer may be at least two kinds selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and block- have.

INDUSTRIAL APPLICABILITY As described above, the self-adhesive protective film according to the present invention can provide a self-adhesive protective film having a multilayer structure composed of a pressure-sensitive adhesive layer comprising a polystyrene-based copolymer and an ethylene vinyl alcohol copolymer and a support layer, It is possible to provide a self-adhesive protective film having improved mechanical properties such as heat resistance.

Further, the present invention can provide a self-adhesive protective film free from residues.

Hereinafter, the present invention will be described in more detail with reference to examples and the like, but the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

The self-adhesive protective film according to the present invention comprises a support layer; And an adhesive layer formed on one or both surfaces of the support layer, the adhesive layer comprising a polystyrene elastomer and an ethylene vinyl alcohol copolymer (EVOH).

As described above, the self-adhesive protective film according to the present invention is excellent in mechanical properties such as adhesiveness, cuttability and heat resistance by including the polystyrene-based elastomer and the ethylene vinyl alcohol copolymer in the adhesive layer, A protective film can be provided.

As used herein, the term 'self-tackiness' used in the present invention means that no other adhesive is used, no additional pressure or heat is applied, and no mechanical means such as pushpins, screws, staples, nails, Means the property of a film that can be adhered to a surface.

The term " protective film " used in the present invention means a film that adheres to the surface to be protected of the adherend to protect the adherend so that scratching or peeling does not occur.

Typically, an elastomer is a synthetic polymeric material similar in character to rubber, which, when modified, has the property of returning to its original shape, i.e., resilient, vaginal, not worn and chemically resistant. The elastomer has a high adhesive strength but is difficult to be separated again after bonding, so that it is difficult to exhibit self-adhesive property, and it is difficult to manufacture the film in the form of a film because of its cohesive property.

In the present invention, a mixture obtained by mixing an elastomer with a styrenic system in an appropriate blend ratio, that is, a polystyrene elastomer, is provided in the adhesive layer in order to utilize the high adhesive force of the elastomer and impart easiness of film formation.

First, the self-adhesive protective film of the present invention may contain a polystyrene-based elastomer and an ethylene vinyl alcohol copolymer in an adhesive layer, wherein the polystyrene-based elastomer is contained in an amount of 40 to 70% by weight based on the total weight of the adhesive layer, And the vinyl alcohol copolymer is 10 to 30% by weight.

As a result of experiments conducted by the present inventors, it has been found that it is difficult to expect the above-described effect when the composition is out of the above range.

Specifically, when the polystyrene-based elastomer is less than 40% by weight based on the total weight of the adhesive layer, the adhesive strength may be lowered and the elastic modulus may become excessively high. On the other hand, if it exceeds 70% by weight, it may be difficult to form a film due to poor compatibility with an ethylene vinyl alcohol copolymer, and it may be difficult to peel off from the adherend due to high adhesive strength. As a result, There is a possibility of occurrence.

The polystyrene-based elastomer may be included in the pressure-sensitive adhesive layer in order to secure high adhesion and thermal stability. Examples of the pressure-sensitive adhesive layer include SEBS (styrene- (ethylene / buthylene) -styrene block copolymer), crystalline block- (ethylene / ) -crystalline block copolymer, HSBR (Hydrogenated styrene butadiene rubber), SEBC (styrene- (ethylene / buthylene) -crystalline block copolymer), SEEPS (polystyrene- -OH (polystyrene-block-poly (ethylene / propylene) -block-hydroxyl-polystyrene, SIBS (styrene-isobutylene-styrene triblock copolymer) SEP poly (ethylene / propylene) -block-polystyrene), but the present invention is not limited thereto.

In order to minimize the difference between the initial adhesion and the late adhesion, the self-adhesive protective film of the present invention may contain an ethylene vinyl alcohol copolymer in the adhesive layer composition, and the ethylene vinyl alcohol copolymer may contain ethylene and / But are not limited to, copolymers polymerized by Hydrolysis or Alcohloysis.

As described above, the ethylene vinyl alcohol copolymer is preferably 10 to 30% by weight based on the total weight of the pressure-sensitive adhesive layer. When it is more than 30% by weight, the adhesive strength may be deteriorated. When it is less than 10% There is a problem that the difference between the initial adhesive force and the late adhesive force becomes large and the peeling force is lowered, which is not preferable.

In some cases, the adhesive layer of the present invention may further include an adhesive force adjusting agent, a tackifier resin, and the like.

The adhesion modifier may be used to easily adjust the adhesive force required for the adherend, and may be added in an amount of 25 to 35% by weight based on the total weight of the adhesive layer. The adhesive force adjusting agent is preferably an elastomer having a lower tackiness than the polystyrene type elastomer, and more preferably, the adhesive force of the tack strength adjusting agent may be 60% or less of the adhesive force of the polystyrene type elastomer.

Specific examples thereof may include at least one selected from the group consisting of ethylene, propylene, acrylonitrile, butadiene, acrylic, isoprene, polyurethane, and silicone. Preferably, an ethylene-based elastomer having good compatibility with the polystyrene-based elastomer and having a small difference in adhesion between the two elastomers can be used.

The ethylenic elastomer can be divided into a random copolymer and a block copolymer. When the density of the random copolymer is 0.880 or less, the softening point is low and it is difficult to secure the thermal stability of the protective film. On the other hand, Even though the copolymer has a density of 0.880 or less, the softening point is high and the thermal stability of the protective film can be secured. Therefore, it is more preferable to use an ethylene-based elastomer block copolymer.

On the other hand, the tackifying resin may be usually added in an amount of less than 5 to 15% by weight based on the total weight of the adhesive layer. Such a tackifier resin is not particularly limited as long as it can increase the tackiness without causing chemical change when added to the pressure-sensitive adhesive layer. For example, the tackifier resin may be an oil such as an aliphatic or aromatic, aliphatic or aromatic copolymer Based resin, a terpene-phenol resin, an alkylphenol resin, a coumarone-indene resin, a rosin resin, a paraffin oil, a naphthene oil, an aromatic oil, castor oil, tall oil, Phenol resin and the like can be used.

The tackifier resin may preferably be a petroleum resin having excellent adhesion at low pressure between the protective film and the adherend during laminating.

The tackifier resin preferably has a weight average molecular weight (Mw) of 900 to 1500 or less. If the weight average molecular weight is less than 900, residues may occur. If the tackifier resin has a weight average molecular weight of more than 1500, the workability may deteriorate. More preferably, the Mw of the tackifier resin is preferably 1000 to 1400 or less.

The self-adhesive protective film of the present invention can be suitably blended with the above compositions to produce an adhesive layer having a thickness of 10 to 20 mu m.

On the other hand, the substrate for forming the support layer in the present invention is not particularly limited, but may be a low density polyethylene (LDPE), a linear low density polyethylene (LLDPE), a medium density polyethylene (MDPE), a high density polyethylene (HDPE) -Propylene Block Copolymer) may be used. Among these, in particular, it is preferable to mix Block-PP and HDPE, or mix LDPE and HDPE, or MDPE and HDPE in consideration of cuttability and workability of the self-adhesive protective film. At this time, the resin composition of the support layer used is generally blended and used, but not always limited thereto.

The thickness of the support layer is preferably 1 to 200 탆, more preferably 1 to 100 탆.

The compositions corresponding to the respective layers of the film may be put into a hopper to produce the desired self-adhesive protective film of the present invention.

Specifically, when the composition of the adhesive layer is put into the hopper, the composition of the adhesive layer can be moved to one side while the screw rotates. At this time, the adhesive layer composition is melted at 210 to 220 ° C and supplied to one side. The melted composition can be extruded by a conventional single-screw or twin-screw extruder to form an adhesive layer. In the same manner, a support layer is sequentially formed on the pressure-sensitive adhesive layer and pressurized to produce the self-adhesive protective film of the present invention.

{Example}

Material Information

- SIBS: Kaneka's 062M, density 0.947

- Ethylene vinyl alcohol copolymer (EVOH): NF518E from Mitsui, density 0.910

- Petroleum resin (A): R1125 from Eastman, weight average molecular weight 1300

  Petroleum resin (B): R1010 from Eastman, weight average molecular weight 800

Adhesion modifier (A): Dow 9500 (block copolymer), density 0.877

  Adhesion modifier (B): Dow 8852G (random copolymer), density 0.875

- LDPE: Melting Index 5.5, density 0.922

- MDPE: Melting Index 5.0, density 0.938

- HDPE: Melting Index 6.5, density 0.962

- Block-PP: Melting Index 7.0, density 0.900

≪ Example 1 >

A pressure-sensitive adhesive layer composition comprising 60% by weight of SIBS, 10% by weight of a petroleum resin (A) and 30% by weight of an ethylene vinyl alcohol copolymer as a polystyrene type copolymer and 5% by weight of HDPE and 95% The support layer was co-extruded by the T-die method to prepare a self-adhesive protective film having a thickness of 12 탆 on the 48 탆 thick support layer.

≪ Example 2 >

In the same manner as in Example 1 except that the composition of the pressure-sensitive adhesive layer in Example 1 was 70% by weight of SIBS, 10% by weight of petroleum resin (A) and 20% by weight of ethylene vinyl alcohol copolymer, A protective film was prepared.

≪ Example 3 >

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 50 wt% of SIBS, 35% of the adhesion modifier (A), 5 wt% of the petroleum resin (A), and 10 wt% A self-adhesive protective film was prepared.

<Example 4>

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 50 wt% of SIBS, 30% of the adhesion modifier (A), 10 wt% of the petroleum resin (A), and 10 wt% A self-adhesive protective film was prepared.

&Lt; Example 5 >

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 50% by weight of SIBS, 25% by weight of the adhesion modifier (A), 5% by weight of petroleum resin (A) and 20% by weight of ethylene vinyl alcohol copolymer A self-adhesive protective film was prepared.

&Lt; Example 6 >

Example 1 was repeated except that the pressure-sensitive adhesive layer composition of Example 1 was composed of 50 wt% of SIBS, 20% of the adhesion modifier (A), 10 wt% of petroleum resin (A) and 20 wt% of ethylene vinyl alcohol copolymer A self-adhesive protective film was prepared.

&Lt; Example 7 >

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 50 wt% of SIBS, 15% of the adhesion modifier (A), 15 wt% of petroleum resin (A), and 20 wt% A self-adhesive protective film was prepared.

&Lt; Example 8 >

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 50% by weight of SIBS, 15% by weight of the adhesion modifier (A), 10% by weight of petroleum resin (A) and 25% by weight of ethylene vinyl alcohol copolymer A self-adhesive protective film was prepared.

&Lt; Example 9 >

Example 1 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer composition was composed of 40 wt% of SIBS, 25 wt% of adhesion modifier (A), 10 wt% of petroleum resin (A), and 25 wt% of ethylene vinyl alcohol copolymer A self-adhesive protective film was prepared.

&Lt; Example 10 >

A self-adhesive protective film was prepared in the same manner as in Example 1 except that the support layer was composed of 70% by weight of LDPE and 30% by weight of HDPE.

&Lt; Example 11 >

A self-adhesive protective film was prepared in the same manner as in Example 1 except that the support layer was composed of 50 wt% of LDPE and 50 wt% of HDPE.

&Lt; Example 12 >

In Example 1, a self-adhesive protective film was prepared using the same method as in Example 1, except that the support layer was composed of 80% by weight of MDPE and 20% by weight of HDPE.

&Lt; Example 13 >

A self-adhesive protective film was prepared in the same manner as in Example 1, except that the support layer was composed of MDPE 60 wt% and HDPE 40 wt%.

&Lt; Example 14 >

A self-adhesive protective film was prepared in the same manner as in Example 1, except that the support layer was composed of 90 wt% of HDPE and 10 wt% of Block-PP.

&Lt; Example 15 >

A self-adhesive protective film was prepared in the same manner as in Example 1 except that the support layer was composed of 70% by weight of HDPE and 30% by weight of Block-PP.

&Lt; Comparative Example 1 &

A commercially available coated adhesive type protective film (Novacel, 9832) was used.

&Lt; Comparative Example 2 &

A commercially available self-adhesive type protective film (POLYFILM, CR-205) was used.

&Lt; Comparative Example 3 &

A self-adhesive protective film was prepared in the same manner as in Example 3, except that 5% by weight of the petroleum resin (B) as the pressure-sensitive adhesive layer was used.

&Lt; Comparative Example 4 &

A self-adhesive protective film was produced in the same manner as in Example 3, except that 35% by weight of the adhesion modifier (B) of the adhesive layer in Example 3 was used.

&Lt; Comparative Example 5 &

A self-adhesive protective film was prepared in the same manner as in Example 1, except that the support layer was 100% by weight of LDPE.

&Lt; Comparative Example 6 >

In Example 1, a self-adhesive protective film was produced using the same method as in Example 1 except that the support layer was 100% by weight of MDPE.

&Lt; Comparative Example 7 &

A self-adhesive protective film was prepared in the same manner as in Example 1, except that the support layer was 100 wt% of Block-PP.

{evaluation}

The properties of the film were measured by the following evaluation method for the prepared or purchased protective film.

1. Adhesion measurement

(1) Initial adhesive strength (peel strength)

The films prepared in Examples and Comparative Examples were cut into 25 mm × 20 cm (width × length) and attached to the pattern light guide plate. After 30 minutes, the adhesive strength was measured according to KST 1028.

(2) Late adhesion (peel strength)

The peel strength was measured in the same manner as in the initial peel strength measurement described above except that the adhesive strength was measured after 2 days from the attachment.

2. Adhesion measurement by laminating machine pressure

(1) 0.1 MPa

After applying a pressure of 0.1 MPa using a laminator to the pattern light guide plate, the adhesive strength was measured according to KST 1028 after 30 minutes.

(2) 0.3 MPa

After applying a pressure of 0.3 MPa using a laminator to the pattern light guide plate, the adhesive strength was measured according to KST 1028 after 30 minutes.

(3) 0.5 MPa

After applying a pressure of 0.5 Mpa using a laminator to the pattern light guide plate, the adhesive strength was measured according to KST 1028 after 30 minutes.

3. Measurement of thermal stability

(1) room temperature

The film was attached to the pattern light guide plate and allowed to stand at room temperature for 1 hour. Then, the adhesive strength was measured according to KST 1028 to evaluate the thermal stability.

(2) 50 DEG C

The film was attached to the pattern light guide plate and allowed to stand at 50 DEG C for 1 hour, and the adhesive strength was measured according to KST 1028 to evaluate the thermal stability.

(3) 80 DEG C

The film was attached to a pattern light guide plate and allowed to stand at 80 DEG C for 1 hour, and the adhesive strength was measured according to KST 1028 to evaluate the thermal stability.

4. Measurement of cuttability

The cutability of the protective film was evaluated by comprehensively judging whether the film was attached to the pattern light guide plate and whether it was easy to cut, whether the edges were lengthened, whether powder was generated, and the like. (?: Very good,?: Good,?: Fair, X: poor)

5. Measurement of residue

The film was attached to the pattern light guide plate, allowed to stand at 60 DEG C for 2 days, peeled off, and the substance remaining on the light guide plate was visually evaluated (O: present, X: none)

The measurement results are shown in Table 1 below.

division Adhesion (gf / 25mm) Depending on the pressure of the laminator
Adhesion (gf / 25mm) Thermal Stability (gf / 25mm) Residue
Whether Cutting ability Early review 0.1Mpa 0.3Mpa 0.5 Mpa Room temperature 50 ℃ 80 ℃ Comparative Example 1 43 51 31 37 43 43 47 54 O O Comparative Example 2 39 50 26 32 39 39 52 86 X O Comparative Example 3 49 55 46 50 51 - - - O - Comparative Example 4 45 51 - - - 45 158 298 O - Comparative Example 5 45 46 - - - - - - X X Comparative Example 6 44 45 - - - - - - X X Comparative Example 7 42 42 - - - - - - X Δ Example 1 42 43 39 40 42 42 44 47 X O Example 2 49 49 47 47 49 49 51 52 X ◎ Example 3 41 43 39 40 41 41 44 47 X ◎ Example 4 50 51 47 48 50 50 53 55 X ◎ Example 5 48 48 44 47 48 48 50 51 X ◎ Example 6 51 52 48 50 51 51 53 56 X ◎ Example 7 56 56 54 54 56 56 57 59 X ◎ Example 8 48 49 46 48 48 48 51 54 X ◎ Example 9 43 43 40 41 43 43 46 47 X ◎ Example 10 42 42 - - - - - - X O Example 11 43 44 - - - - - - X ◎ Example 12 42 42 - - - - - - X ◎ Example 13 42 43 - - - - - - X ◎ Example 14 43 43 - - - - - - X ◎ Example 15 42 43 - - - - - - X ◎

(1) Evaluation of cohesion

Comparing the difference between the initial adhesion and the late adhesion in Table 1, it can be seen that Examples 1 to 15 have an average of 0.6 gf / 25 mm and Comparative Examples 1 to 7 have an average of 4.7 gf / 25 mm. The late adhesive force is generally larger than the initial adhesive force. However, the larger the difference is, the lower the peeling force and the peeling force can not be easily released from the adherend (light guide plate). Therefore, it is preferable that the difference between the initial adhesion and the late adhesion is not large, and it can be seen that the self-adhesive protective film produced according to one embodiment of the present invention is excellent in adhesion and peel strength.

(2) Evaluation of adhesion according to the pressure of the laminating machine

Referring to Table 1, in Examples 1 to 9, it can be seen that the change of adhesive force according to the pressure of the laminating machine is not large.

Specifically, the difference between 0.1 MPa and 0.5 MPa in Examples 1 to 9 was 2.67 gf / 25 mm on the average, and it was confirmed that the change of the adhesive force according to the pressure was small and the peeling was easily possible from the light guide plate.

On the other hand, the difference between 0.1 MPa and 0.5 MPa in Comparative Examples 1 to 3 is 10 gf / 25 mm on average, and the change with pressure is about 4 times larger than that in the Example. As a result, it was found that the protective film prepared according to Comparative Examples 1 to 3 was difficult to peel off from the light guide plate, and adhesive residue remained on the light guide plate.

(3) Evaluation of thermal stability

From the measurement results of the thermal stability of Examples 1 to 9, it was confirmed that the thermal stability was extremely small because the dimensional change by heat was extremely small.

Specifically, the adhesive strength at room temperature and at 80 ° C was 11 gf / 25 mm for Comparative Example 1, 47 gf / 25 mm for Comparative Example 2, and 253 gf / 25 mm for Comparative Example 4. On the other hand, it was confirmed that the adhesive strength difference of Examples 1 to 9 was 4.44 gf / 25 mm on average, which was about 23.5 times smaller than Comparative Examples 1, 2 and 4.

This means that the adhesive force of the self-adhesive protective film produced according to an embodiment of the present invention is not easily changed by heat, and thus the peeling force is not lowered, so that it can be easily peeled off from the adherend. Further, it was confirmed that there was no adhesive residue.

On the other hand, in Comparative Example 4 using the random copolymer, the adhesive strength at room temperature was 45 gf / 25 mm and the adhesive strength at 80 ° C was 298 gf / 25 mm. As the temperature increased, The increase value is larger than that of Comparative Example 2. That is, it was confirmed that the use of the ethylene-elastomer random copolymer other than the ethylene elastomer block copolymer deteriorated the thermal stability, that is, the heat resistance.

(4) Evaluation of cutability

The cutting properties of Examples 1 to 15 were examined. When the film was adhered to the light guide plate and cut to a predetermined size, it was confirmed that the edges were not elongated and the overall cut was easy. On the other hand, in Comparative Examples 5 to 7, edges were partially elongated at the time of cutting, and powder and the like were generated. Particularly, in Comparative Example 5 and Comparative Example 6, when the cutting was performed, edges were stretched to make it difficult to cut into a film of a desired size, so that some extrusion occurred at the cut portion.

This is because the support layer of the self-adhesive protective film produced according to an embodiment of the present invention is an ethylene-based copolymer or a polypropylene-based polymer, which is not an ethylene-based polymer or a polypropylene- It was confirmed that the present invention has excellent cutability.

(5) Evaluation of residue

Referring to Table 1, in Examples 1 to 15, the adhesive was adhered to the light guide plate and left for 48 hours. After peeling off the protective film, adhesive residue was not generated. On the other hand, in the case of Comparative Example 1 and Comparative Examples 3 and 4 which were the coating adhesive type protective films, it was confirmed that residual adhesive remained on peeling, and there was an inconvenience of additionally using a solvent to remove the residue.

Comparing the results of Examples 1 to 15 and Comparative Examples 1 to 7 in a comprehensive manner, it can be seen that the adhesion of the self-adhesive protective film produced according to one embodiment of the present invention is similar or excellent, And the like.

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

Claims (9)

Supporting layer; And
An adhesive layer formed on one side or both sides of the support layer and including a polystyrene elastomer and an ethylene vinyl alcohol copolymer (EVOH);
Respectively,
Wherein the adhesive layer further comprises an adhesive force adjusting agent,
Wherein the adhesion-modifying agent is an elastomer having lower adhesiveness than the polystyrene-based elastomer. The method according to claim 1,
Wherein the polystyrene-based elastomer in the pressure-sensitive adhesive layer is 40 to 70% by weight based on the total weight of the pressure-sensitive adhesive layer, and the ethylene-vinyl alcohol copolymer is 10 to 30% by weight. The method according to claim 1,
Examples of the polystyrene elastomer include SEBS (styrene- (ethylene / buthylene) -styrene block copolymer, crystalline block- (ethylene / buthylene) -crystalline block copolymer (CEBC), hydrogenated styrene butadiene rubber (HSBR) (ethylene-ethylene / propylene) -block polystyrene (SEEPS), polystyrene-block-poly (ethylene-ethylene / propylene) -block-hydroxyl-polystyrene , Polystyrene-block-poly (ethylene / propylene), and SEPS (polystyrene-block-poly (ethylene / propylene) -block-polystyrene) Wherein the self-adhesive protective film is characterized by: The method according to claim 1,
Wherein the pressure-sensitive adhesive layer further comprises a tackifier resin. 5. The method of claim 4,
Wherein the tackifier resin has a weight average molecular weight (Mw) of 900 to 1,500 or less. The method according to claim 1,
Wherein the adhesion modifier is contained in an amount of 15 to 50 wt% based on the total weight of the adhesive layer. delete The method according to claim 1,
Wherein the elastomer having lower adhesiveness than the polystyrene elastomer is at least one selected from the group consisting of ethylene, propylene, acrylonitrile, butadiene, acrylic, isoprene, polyurethane and silicone. . The method according to claim 1,
The supporting layer may be at least two selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and block-PP (Poly-Propylene Block Copolymer) A self-adhesive protective film.