KR20080059950A - Surface protective film - Google Patents

Abstract

A surface protective film is provided to remove foreign materials generated during a process by peeling the upper surface protective film from an optical film, wherein the upper surface protective film has an adhesive force different from that of the lower surface protective film by a proper degree. A surface protective film consists of upper and lower surface protective films which are attached to the upper and lower surfaces of an optical film respectively. The adhesive force of an adhesive layer of the upper surface protective film is seven to eight times as large as that of an adhesive layer(3a) of the lower surface protective film. The adhesive layer of the lower surface protective film contains aryl resin 100 parts by weight, isocyanate based curing agent 1~20 parts by weight, and general solvent 10~30 parts by weight.

Description

Surface protective film

1A is a schematic view showing a bottom plate surface protective film configuration according to one embodiment of the present invention.

1B is a schematic view showing the configuration of an optical film according to one embodiment of the present invention.

1C is a schematic view showing a top surface protective film according to one embodiment of the present invention.

* Description of Major Reference Marks *

1a, 1b, 1c: base film 2a: primer layer

3a, 3c: adhesive layer 4a, 4c: release film

5b diffusion layer 6b anti blocking layer

7c: antistatic layer

This invention relates to the surface protection film by which the adhesive force of the upper board and the lower board was adjusted in the surface protection film used for an optical protective film etc.

The surface protective film is usually adhered up and down of an optical film (hereinafter referred to as an "optical film") such as a diffusion sheet, and the top plate surface protection film and the bottom plate are attached to the top of the optical film. It is called a surface protection film.

In order to manufacture such a surface protection film, first, a lower surface protection film is affixed on an optical film, and the optical film and lower surface protection film which were affixed are carried out. Subsequently, the unnecessary optical film portion is removed and the top surface protective film is attached.

By the way, the conventional surface protection film has the following problem.

That is, although the lower plate surface protective film has a small adhesive force, since the surface roughness of the optical film side to which the lower plate surface protective film is attached is hardly adhered, adhesion is possible, but the upper plate surface protective film is formed on the optical film side to which the upper plate surface protective film is attached. Due to the high surface roughness, when the adhesive force is small, the winding and unwinding operations are not easy, and it is difficult to be protected from foreign matter or the external environment. Therefore, although the adhesive force of a top plate surface protection film needs to be enlarged, when an adhesive force of an upper plate surface protection film is too large, an optical film will peel together at the time of peeling a top plate surface protection film.

Accordingly, there is a need for a surface protection film that can be easily wound and unwinded from the surface protection film, can be protected from foreign substances or the external environment, and has no problem that the optical film is peeled off together.

The present invention is to solve the problems of the prior art as described above, an object of the present invention, the winding and unwinding of the optical film with a surface protection film is easy to work and can be protected from the external environment, during the process It is to provide a surface protection film that can remove the foreign matter that is generated, and the adhesive force of the upper plate and the lower plate without the problem that the optical film is peeled together when removing the upper surface protective film having a large adhesive force during the process.

In order to achieve the above object, in the present invention, as a surface protection film having an upper plate and a lower plate surface protective film adhered up and down of an optical film, the adhesive force of the pressure-sensitive adhesive layer of the upper plate surface protective film is the lower plate surface protective film. The upper plate and the lower plate, characterized in that 7 to 8 times larger than the adhesive force of the pressure-sensitive adhesive layer of the surface protective film provided with the adhesive force is controlled.

In one embodiment of the present invention, when the average lower surface roughness of the optical film is 0.5 to 5㎛ the adhesion of the pressure-sensitive adhesive layer of the lower plate surface protective film is in the range of 1 to 3gf, of the optical film When the average top surface roughness is 6 to 15 µm, the adhesive force of the pressure-sensitive adhesive layer of the top surface protective film is preferably in the range of 7 to 24 gf.

In one embodiment of the present invention, the pressure-sensitive adhesive layer of the lower surface protection film is 100 parts by weight of the acrylic resin of the subject; 1 to 20 parts by weight of isocyanate curing agent; It is preferable that it consists of an adhesive composition containing 10-30 weight part of normal solvents, and it is preferable that an antistatic agent is further contained in the said adhesive composition.

In one embodiment of the present invention, the pressure-sensitive adhesive layer of the lower plate surface protection film is 70 to 100 parts by weight of polydimethylsiloxane checker resin as the main subject; 10 to 40 parts by weight of MQ resin; It is preferable that the pressure-sensitive adhesive composition comprising 100 to 150 parts by weight of a common solvent. In addition, it is preferable that anchorage agent, which is dimethylvinylsiloxane, is further added in an amount of 1 to 5 parts by weight, and a crosslinking agent, which is polymethylhydrogen siloxane, is further added in an amount of 0.5 to 5 parts by weight, tin or platinum. It is preferred that the catalyst is further added in 0.5 to 2 parts by weight.

In one embodiment of the present invention, the pressure-sensitive adhesive layer of the upper surface protective film is 100 parts by weight of the acrylic resin of the subject; 1 to 10 parts by weight of isocyanate curing agent; And it is preferable that it consists of an adhesive composition containing 20-50 weight part of normal solvents.

In one embodiment of the present invention, the lower plate surface protection film is a base film; A primer layer formed on the base film; And the pressure-sensitive adhesive layer formed on the primer layer, wherein the primer layer is a coating layer of a primer composition including a main material, a polyorganosiloxane crosslinking agent, a common catalyst, and a common solvent as a silane coupling agent. , With respect to the total weight of the main ingredient and the solvent, the content of the main content of the solid content is 5 to 20wt%.

In one embodiment of the invention, the coating thickness of the primer composition is preferably 0.1 ~ 1㎛.

In one embodiment of the present invention, the viscosity of the primer composition is preferably 10 to 300cps.

In one embodiment of the present invention, the primer layer is 20 parts by weight of the main component of the solid, 1 to 10 parts by weight of crosslinking agent of polyorganosiloxane, 1 to 5 parts by weight of a common catalyst and 80 to 380 parts of a common solvent. As the coating layer of the primer composition comprising a portion, the viscosity of the primer composition is preferably 10 to 300cps.

In one embodiment of the invention, the subject preferably contains a vinyl group.

In one embodiment of the invention, the polyorganosiloxane preferably has Si-H.

Hereinafter, the surface protection film adjusted the adhesive force of the upper plate and the lower plate according to the present invention will be described in detail.

FIG. 1A is a schematic diagram showing a constitution of a lower plate surface protection film according to one embodiment of the present invention, and FIG. 1B is a schematic diagram showing an optical film (diffusion sheet) configuration according to one embodiment of the present invention, and FIG. It is a schematic diagram which shows the structure of the upper surface protection film which concerns on one Example of this invention.

As shown in FIG. 1A, the lower plate surface protective film has an adhesive layer 3a formed thereon with a primer layer 2a on the base film 1a, and a release film (on the adhesive layer 3a). 4a) are stacked. As shown in FIG. 1B, in the optical film (diffusion sheet), a diffusion layer 5b having a relatively large surface roughness is formed on one surface of the substrate film 1b, and on the surface of the substrate film 1b on the opposite side. An anti blocking layer 6b having a relatively small surface roughness is formed. As shown in FIG. 1C, the upper surface protective film has a pressure-sensitive adhesive layer 3c formed under the base film 1c and a release film 4c laminated thereunder, and an optional surface on the opposite surface of the base film 1c. The antistatic layer 7c is formed.

In the present invention, the adhesive force of the pressure-sensitive adhesive layer of the upper plate surface protection film and the adhesive force of the pressure-sensitive adhesive layer of the lower plate surface protection film are adjusted, respectively, so that the adhesive force of the upper plate surface protection film is 7 to 8 times as compared to the adhesive force of the lower plate surface protection film. do. In this way, the adhesive force of the upper and lower surface protective films must be adjusted to have a mutually different difference (7 to 8 times) to facilitate the winding and unwinding operation without peeling off the optical film when the surface protective film is peeled off. In particular, it is possible to obtain an effect that the foreign matter is removed by the adhesive force of the top surface protective film, especially in the domosong processing.

Each adhesive force in the upper and lower surface protective films should be larger as the roughness of the upper and lower surfaces of the optical film becomes larger. Typically, the lower surface roughness of the optical film is 0.5 to 5 탆 on average, and The top surface roughness of the film for averages is 6-15 micrometers on average. In consideration of such roughness, the adhesive force of the upper plate is preferably adjusted in the range of 7 to 24 gf, and the adhesive force of the lower plate is preferably adjusted in the range of 1 to 3 gf.

Examples of the configuration of the upper and lower plate surface protection films are as follows.

First, a lower surface protection film is explained in full detail.

First, the base film of the lower plate surface protective film is a conventional one, for example, PET, PE, OPP, NY, PI, nylon and the like. In the case of PET film, it is usually formed in 75㎛, OPP is formed in 100㎛. However, while the optical film is 100% cut during the domosong processing, the base film of the lower surface protection film should have a thickness of at least 70 μm in case of half cutting. In addition, the base film may be corona treatment to increase the adhesion with the primer layer to be described later.

In a lower surface protection film, an acrylic adhesive or a silicone adhesive is used for an adhesive layer.

The acrylic resins used as the subject of the acrylic pressure-sensitive adhesives are acrylic resins having a high molecular weight of about 200,000 to 1 million [butyl acrylate, ethylene methacrylate methyl copolymer resin (EMMA), ethylene acrylate ethyl copolymer resin (EEA), methyl ethylene acrylate. Copolymer resin (EMA) etc.], and a hardening | curing agent and a solvent are used other than the acrylic resin which is a subject.

The curing agent is an isocyanate-based curing agent, it is particularly preferred to add 1 to 20 parts by weight based on 100 parts by weight of the main ingredient. If the curing agent is less than 1 part by weight, it may not be sufficiently cured, and a pressure may occur in the pressure-sensitive adhesive layer. If the curing agent is more than 20 parts by weight, the curing agent may be excessively cured, resulting in burrs of white powder when cutting the surface protection film. have. The solvent is conventionally used, for example, ethyl acetate, and is mixed with 10 to 30 parts by weight based on 100 parts by weight of the subject matter.

The acrylic pressure-sensitive adhesive may be used to further include an antistatic agent, such antistatic agent by adding one or two or more known antistatic agents such as alkali metal salts, organic-inorganic conductive polymers, and other surfactants in a conventional content Can be used As the alkali metal salt, however, lithium amide (LiNH ₂ ) or lithium diethylamide ((LiN (C ₂ H ₅ ) ₂ )) is more preferable in terms of surface resistance and peeling charge performance.

As the method for producing the acrylic pressure-sensitive adhesive composition, the main ingredient and the solvent are put into the corresponding composition and stirred for 10 minutes, and then the curing agent and the antistatic agent are put into the stirrer with the corresponding composition and mixed for 10 minutes.

Finally, the release film laminated on the acrylic pressure-sensitive adhesive is a silicone release coating after the siloxane antistatic coating excellent compatibility with silicone, for example, 25㎛ PET film to prevent foreign matter adhesion by the silicon during peeling, further An antistatic treatment may be performed on the silicon release film. Accordingly, it is possible to minimize foreign matter mixing due to static electricity that may occur during the skin adhesion process and the lamination process.

On the other hand, the silicone pressure-sensitive adhesive is particularly preferably 70 to 100 parts by weight based on polydimethylsiloxane, and in order to impart adhesion thereto, it is preferable to use MQ resin in 10 to 40 parts by weight in terms of adhesion and control.

The MQ resin is composed of a monofunctional M unit represented by the general formula R ₃ SiO- and a tetrafunctional Q unit represented by SiO ₄ −, and has the general formula of the following [Formula 1].

In blending the subject and the MQ resin, the higher the content of the MQ resin, the higher the adhesion. As described above, since the lower surface roughness of the diffusion sheet is 0.5 to 5 μm, the adhesive force in the lower plate surface protective film is mixed with 10 to 40 parts by weight of the MQ resin with respect to 70 to 100 parts by weight of the main ingredient to adjust the adhesive strength in the range of 1 to 3 gf. It is desirable to be.

It is preferable to add the anchorage agent of dimethylvinylsiloxane to the mixed composition of the said subject and MQ resin, and it is more preferable to add the dimethylvinylsiloxane anchorage agent which further contains a silane coupling agent.

The anchorage agent is more preferably added in an amount of 1 to 5 parts by weight for the linkage between the pressure-sensitive adhesive layer and the primer layer. When the anchorage agent is added in less than 1 part by weight, the link is not good and may cause burrs, and exceeding 5 parts by weight is not necessary because it is unnecessary excess addition and may act as a foreign matter.

It is preferable to add a crosslinking agent which is polymethylhydrogensiloxane to the mixed composition of the said main body and MQ resin, and it is more preferable to add 0.5-5 weight part at this time. If the crosslinking agent is less than 0.5 parts by weight, it is difficult to obtain the desired adhesive force due to the failure to induce adequate curing. It is not preferable that the crosslinking agent is more than 5 parts by weight because it may be an unnecessary excess addition and may act as a foreign matter.

It is preferable to add tin and a platinum catalyst to the mixed composition of the said subject, an MQ resin, an anchorage agent, and a crosslinking agent, and it is especially preferable to add 0.5-2 weight part. If the catalyst is less than 0.5 parts by weight, as in the case of the crosslinking agent, it is difficult to obtain a desired adhesive force due to the inadequate hardening, and it is not preferable that the catalyst is more than 2 parts by weight because it is an unnecessary excess addition and may act as a foreign matter.

In the case of the lower plate surface protective film using a silicone pressure sensitive adhesive, it is preferable to further form a primer layer. The primer layer not only prevents the adhesive from transferring to the diffusion sheet, but also prevents the adhesive from falling off from the base film due to humidity. In addition, it is possible to prevent cracking and slipping during the transfer, and also to prevent blocking when rewinding the tape.

Here, the primer layer includes a main material, a crosslinking agent, a catalyst, a solvent, and the like, and in this case, it is preferable to use a crosslinking agent which is a main material and a polyorganosiloxane, in particular. The silane coupling agent uses, for example, aminopropyltrimethoxysilane or glycidoxypropyltrimethoxysilane, where the subject is more preferably particularly containing vinyl groups. On the other hand, it is more preferable to use the polyorganosiloxane which has Si-H as said crosslinking agent. In the case of the silane coupling agent containing a vinyl group, it contains Si- (CH = CH ₂ ) structure and reacts with the polyorganosiloxane containing Si-H in the presence of a catalyst, and thus -Si-CH ₂ -CH _2- Si- is formed. On the other hand, the vinyl group of the subject is particularly preferred in the role of the base film and the pressure-sensitive adhesive layer to obtain excellent solvent resistance and durability, uniform thin film coating property, furthermore firm adhesion and processability.

The main component of the silane coupling agent means a solid content, and by changing the amount of the solvent with respect to the total weight of the solid content and the solvent, the content of the solid content with respect to the total weight of the solid content and the solvent may be adjusted. .

According to the reaction type of the primer used as the conventional catalyst, both tin and platinum can be used, and tin is preferable because tin is cheaper than platinum. The solvent is also common, and toluene, MEK and the like are used, for example.

By adjusting the content of the solid content in the primer composition with respect to the total weight of the solid content and the solvent, it is possible to control the viscosity and thereby to control the coating thickness over a certain thickness to obtain durability, in particular solvent resistance Further, it is possible to prevent the deterioration of adhesion and processability, and to coat a thin film having a uniform thickness and a predetermined thickness or more.

Specifically, when the solid content of the solid content is less than 5wt% with respect to the total weight of the solid content and the solvent, the viscosity becomes less than 10 cps. In this case, it is difficult to uniformly coat a thin film of a constant thickness. When the main content of the solid content is in the range of 5wt% to 20wt% with respect to the total weight of the main body and the solvent, the viscosity is in the range of 300 cps in the range of 10 cps or more. The above uniform thin film can be coated, and also these properties are almost constant. When the main content of the solid content exceeds 20wt% with respect to the total weight of the main material and the solvent, the viscosity exceeds 300 cps. In this case, the thin film coating itself may be difficult due to the excessive viscosity.

In order to control the content of the solid content of the main content and the solvent with respect to the total weight of the solid content, for example, by adjusting the content of the solid content of the main content to 20wt% using 20 parts by weight of the solid content of the main content and 80 parts by weight of the solvent, The amount of phosphorus motif can be adjusted to 10 to 300 cps as previously seen by adjusting the content of solid subject matter to 20 wt% to 5 wt% as it is fixed and additionally adding a solvent.

On the other hand, the primer composition comprising 20 parts by weight of the subject matter and 80 to 380 parts by weight of solvent is preferable because it can improve workability and adhesiveness by containing 1 to 10 parts by weight of the crosslinking agent and 1 to 5 parts by weight of the catalyst. .

When the content of the crosslinking agent is less than 1 part by weight, the cross linking is lowered, resulting in poor bonding strength, poor coating, and burr generation. In addition, when the crosslinking agent exceeds 10 parts by weight, workability may be lowered rather. The more the crosslinking agent is added, it contributes to the improvement of the bonding force, that is, the adhesive itself, so it can act as a foreign material, so if the adhesion is good, it is not necessary to contain any more, and if excessively contained in this way, the workability may be lowered. In this respect, the crosslinking agent is preferably added in an amount of 1 part by weight or more and 10 parts by weight or less.

The catalyst does not play a role when contained in less than 1 part by weight, as in the case in which the crosslinking agent is contained in less than 1 part by weight, the bonding strength between the crosslinking agent and the subject is poor, causing a decrease in coating and burr generation. As more catalyst is added, the bonding force becomes better, but when the catalyst is contained in an amount of more than 5 parts by weight, the bonding strength is the same as in the case of 5 parts by weight, and the catalyst may also act as a foreign substance. It is not desirable because it can.

Coating of the above primer layer is usually made of a gravure coating, in addition, bar coating, reverse coating, spray coating and the like is possible. Here, the drying temperature is dried at 130 to 150 ℃, and dried for 1 minute to coat.

On the other hand, in order to coat the silicone pressure-sensitive adhesive layer on the primer-treated base film using a gravure coating, bar coating, reverse coating, spray coating, etc. to a thickness of 5 to 100㎛, drying temperature is 130 to 150 ℃ The drying time is 1 minute. The viscosity is 500 to 5000 cps, the coating thickness should have a viscosity of at least 500 cps or more to allow uniform coating. Exceeding 5000 cps unnecessarily increases cost.

The release film of the lower surface protection film which used the said silicone type adhesive is formed in 5-10 micrometers normally by protecting a silicone type adhesive layer. It is preferable to use an unactivated film as such a release film, because when the release film is activated, the pressure-sensitive adhesive layer may be transferred when the activated surface and the pressure-sensitive adhesive are in contact with each other. Therefore, it is preferable to use a release film which is not activated, such as a corona-free PET film or a corona-free OPP film without corona treatment.

Next, a top plate surface protection film is explained in full detail.

The base film of the upper surface protective film uses, for example, PET, PE, OPP, NY, PI, nylon and the like as the lower surface protective film. Since the thickness should just be able to be provided with an adhesive layer, what is necessary is just to form in 5-200 micrometers.

An acrylic adhesive and a silicone adhesive can be used as an adhesive layer. However, the use of a silicone pressure sensitive adhesive is disadvantageous in terms of price, so it is preferable to use an acrylic pressure sensitive adhesive composition.

The acrylic pressure-sensitive adhesive composition is mixed with 1 to 10 parts by weight of isocyanate-based curing agent to 100 parts by weight of the main acrylic resin, and 20 to 50 parts by weight of a solvent such as EA.

In the case of the acrylic pressure-sensitive adhesive composition, the adhesive force of the pressure-sensitive adhesive layer is controlled by the combination of the acrylic resin and the hardener, and the more the hardener is added within the range of the hardener, the lower the adhesive force. As described above, the adhesive force is preferably adjusted in the range of 7 to 24 gf because the top surface roughness of the optical film is 6 to 15 μm on average. If the curing agent is less than 1 part by weight, the desired adhesive strength cannot be obtained, and if the curing agent is more than 10 parts by weight, it is not preferable because it causes a problem due to the unnecessary excess addition to cause a problem more than the desired degree. The solvent is mixed in an amount of 20 to 50 parts by weight based on 100 parts by weight of the acrylic pressure sensitive adhesive.

In order to coat the acrylic pressure-sensitive adhesive layer on the base film using a gravure coating, bar coating, reverse coating, spray coating and the like to a thickness of 5 to 50㎛, drying temperature is 100 to 120 ℃, drying time Is 30 seconds to 2 minutes.

The release film of the top surface protective film uses, for example, a PET film coated with silicone. In the case of the antistatic layer 7c, the antistatic composition is composed of, for example, 5 to 20% by weight of conductive polymer (PEDOT / PSS), 10 to 20% by weight of 2-propanol, and 50 to 80% by weight of water, and include gravure, micro gravure, and reverse. Coating by a kiss roll or the like method. At this time, the drying temperature is set to 100 to 120 ° C, and the drying time is set to 30 seconds to 2 minutes.

When the top plate and the bottom plate surface protective film described above, if necessary, color may be added to the top plate to distinguish the top plate and the bottom plate. That is, by forming the color by ink printing between the upper base film and the pressure-sensitive adhesive layer, it is possible to distinguish the upper plate having a color from the lower plate having no color.

Hereinafter, the present invention will be described in more detail by explaining preferred examples and experimental examples of the present invention. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only ordinary in the art while making the disclosure of the present invention complete. It is intended to facilitate the implementation of the invention to those with knowledge.

[Check Average Surface Roughness of Optical Film]

The surface roughness was measured three times by purchasing the product having the roughest surface roughness (diffusion sheet A) and the smoothest product (diffusion sheet B) among the diffusion sheets (manufactured by Kimoto, Japan) which is an optical film.

Table 1 shows the upper and lower surface roughness measurement results of the diffusion sheet A.

Diffusion Sheet A 1 time Episode 2 3rd time Average Top roughness 13.644 μm 14.138 μm 14.941 μm 14.241 µm Roughness 5.428㎛ 3.383 μm 4.118 ㎛ 4.310 μm

Table 2 shows the upper and lower surface roughness measurement results of the diffusion sheet B.

Diffusion Sheet B 1 time Episode 2 3rd time Average Top roughness 6.466㎛ 7.272㎛ 6.136 ㎛ 6.625㎛ Roughness 0.642 μm 0.433 μm 0.693 μm 0.589㎛

As described above, in the diffusion sheet, the roughness is usually in the range of 0.5 to 5 µm, and the top surface is in the range of 6 to 15 µm.

[Top and bottom surface protective film composition]

The lower plate surface protection film formed an adhesive layer on the base film (PET) which is 75 micrometers thick, and formed the release film. As an adhesive composition of the adhesive layer of a lower plate film, the silicone type adhesive composition was comprised as follows first.

80 parts by weight of polydimethylsiloxane (7226, from Dow Corning) as the subject;

20 parts by weight of MQ resin (7657, manufactured by Dow Corning);

2 parts by weight of a dimethylvinylsiloxane anchorage agent (9250, available from Dow Corning);

0.5 part by weight of a polymethylhydrogen siloxane curing agent (7367, manufactured by Dow Corning);

0.5 part by weight of a platinum catalyst;

100 parts by weight of toluene solvent.

On the other hand, as the pressure-sensitive adhesive composition of the pressure-sensitive adhesive layer of the lower plate film, the acrylic pressure-sensitive adhesive composition was configured as follows, and the same experiment as described below was performed.

100 parts by weight of the main acrylic resin (BPS 5978, manufactured by Toyo Ink Co., Ltd.);

5 parts by weight of isocyanate curing agent (BXX5134, manufactured by Toyo Ink Co., Ltd.);

20 parts by weight of ethyl acetate solvent;

3 parts by weight of a lithium amide antistatic agent.

The top plate surface protection film was subjected to an antistatic treatment on an upper side of a base film (PET) having a thickness of 25 μm, and an acrylic pressure-sensitive adhesive layer was formed on a lower side thereof, thereby forming a release film.

The configuration of the antistatic coating solution for the antistatic treatment was as follows.

15% by weight of PEDOT / PSS as the conductive polymer;

15 wt% 2-propanol;

70% by weight of water.

The pressure-sensitive adhesive composition of the acrylic pressure-sensitive adhesive layer was configured as follows.

100 parts by weight of the main acrylic resin (BPS6024, manufactured by Toyo Ink Co., Ltd.);

5 parts by weight of isocyanate curing agent (BXX5134, manufactured by Toyo Ink Co., Ltd.);

30 parts by weight of ethyl acetate solvent.

The lower plate surface protection film was affixed to diffusion sheets A and B (manufactured by Kimoto, Japan) and subjected to domocon processing.

On the opposite side of the diffusion sheet to which the lower plate surface protective film was attached, the upper plate surface protective film was adhered at a pressure of 2 kgf.

[Adhesion Measurement]

Tables 3 and 4 show the results of measuring the upper and lower surface adhesive strengths of the diffusion sheet B.

The following adhesive force measurement result was the same in the case where the adhesive layer of the lower plate surface protection film was formed from the silicone adhesive composition, and each case formed from the acrylic adhesive composition.

Even if the adhesive force is at least 1 gf, the lower plate surface protection film was gentle as about the surface roughness (average 0.5-5 micrometers) of the lower surface of a diffusion sheet, and adhesion was possible. However, since the surface roughness (average 6 to 15㎛) of the top surface of the diffusion sheet is severe, the adhesion was possible only 7gf or more.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Adhesive force on top plate (average surface roughness: 6.625㎛) 1gf 2gf 3gf 4gf 5gf 6gf Bottom plate adhesion (average surface roughness: 0.589㎛) 1gf 1gf 1gf 1gf 1gf 1gf

Example 1 Example 2 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Adhesive force on top plate (average surface roughness: 6.625㎛) 7gf 8gf 9gf 10gf 15gf 20gf Bottom plate adhesion (average surface roughness: 0.589㎛) 1gf 1gf 1gf 1gf 1gf 1gf

Tables 5 and 6 show the results of measuring the top and bottom surface adhesion of the diffusion sheet A.

Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Example 3 Example 4 Adhesive force on top plate (average surface roughness: 14.241㎛) 5gf 10gf 15gf 20gf 21f 22gf Bottom plate adhesion (average surface roughness: 4.310㎛) 3gf 3gf 3gf 3gf 3gf 3gf

Example 5 Example 6 Comparative Example 15 Comparative Example 16 Adhesive force on top plate (average surface roughness: 14.241㎛) 23gf 24gf 25gf 30gf Bottom plate adhesion (average surface roughness: 4.310㎛) 3gf 3gf 3gf 3gf

[Examination evaluation, peeling and unwinding workability, foreign substance removal performance evaluation experiment]

After 3 days, the upper and lower surface protective films of the surface protective films of the Examples and Comparative Examples were peeled off. Peeling rate was 300 mm / min, and peeling angle was 180 degrees. When the measurement was performed 10 times, the case where the top surface protective film and the diffusion sheet were peeled together at least one time was indicated by “×”, and the top plate surface protective film and the diffusion sheet were not peeled together at all. The case was represented by "o".

It was measured whether the top surface protective film peeled off during the winding and unwinding operation. The winding and unwinding operation was measured 10 times, and the case where peeling of the top plate surface protection film occurred at least once or more during winding and unwinding was indicated by "x", and the case where it was not peeled at all was represented by "(circle)".

On the other hand, the peeled surface after peeling off the top surface protective film was visually evaluated to evaluate the extent to which the white powder (burr) and foreign matters introduced into the exterior were removed. The measurement was made 10 times and the case where at least one foreign matter or bur remained was indicated by "x", and the case where no foreign matter or bur remained at all was indicated as "○".

Table 7 shows the measurement results.

Peel off Winding and unwinding workability Foreign material removal performance Example 1 ○ ○ ○ Example 2 ○ ○ ○ Example 3 ○ ○ ○ Example 4 ○ ○ ○ Example 5 ○ ○ ○ Example 6 ○ ○ ○ Comparative Example 1 ○ × × Comparative Example 2 ○ × × Comparative Example 3 ○ × × Comparative Example 4 ○ × × Comparative Example 5 ○ × × Comparative Example 6 ○ × × Comparative Example 7 × ○ ○ Comparative Example 8 × ○ ○ Comparative Example 9 × ○ ○ Comparative Example 10 × ○ × Comparative Example 11 ○ × × Comparative Example 12 ○ × × Comparative Example 13 ○ × × Comparative Example 14 ○ × × Comparative Example 15 × ○ ○ Comparative Example 16 × ○ ○

As in Comparative Examples 7 to 10, 15, and 16, when the upper surface protective film had a much greater adhesive force than the lower surface protective film by 8 times, the diffusion sheet was peeled together when the upper surface protective film was peeled off, causing a problem. .

In Comparative Examples 1 to 6 and 11 to 14, since the adhesive force of the upper surface protective film adhesive strength was weak, the winding and unwinding operations were not easy and foreign matters from the burr removal and external environment which occurred during the process of seedling processing could not be protected.

On the other hand, in the case where the adhesion of the upper plate to the lower plate is 7 to 8 times as in Examples 1 to 6, when the generated foreign matter removes the upper surface protection film, only the foreign matter does not come up along with the diffusion sheet. Removed.

As can be seen from the above, the optical sheet diffusion sheet should never have foreign matters. According to the present invention, even if there are foreign matters generated during processing or transport, the upper and lower surface protective films can remove foreign substances only by adjusting the adhesive force. We can see that it can be removed very easily and neatly.

According to the surface protection film of which the adhesive force of the upper plate and the lower plate of the present invention is controlled, the winding and unwinding of the optical film with the surface protection film is easy and can be protected from the external environment, and the removal of foreign matters generated during the process It is possible. In addition, there is no problem that the optical film is peeled together when removing the upper surface protective film having a large adhesive force during the process.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (11)

As a surface protection film provided with the upper board and lower board surface protection film adhered up and down of the optical film, The adhesive force of the adhesive layer of the said upper plate surface protection film is 7 to 8 times larger than the adhesive force of the adhesive layer of the said lower plate surface protection film, The surface protection film characterized by the above-mentioned. The method of claim 1, When the average lower surface roughness of the optical film is 0.5 to 5㎛ the adhesive force of the pressure-sensitive adhesive layer of the lower plate surface protective film is in the range of 1 to 3gf, the average top surface roughness of the optical film is 6 to 15㎛ When the adhesive strength of the pressure-sensitive adhesive layer of the upper surface protective film is in the range of 7 to 24gf surface protective film. The method of claim 1, The pressure-sensitive adhesive layer of the lower plate surface protection film is 100 parts by weight of the acrylic resin of the main body; 1 to 20 parts by weight of isocyanate curing agent; And 10 to 30 parts by weight of a conventional solvent; Surface protective film comprising a pressure-sensitive adhesive composition comprising. The method of claim 3, wherein The pressure-sensitive adhesive composition further comprises an antistatic agent. The method of claim 1, The pressure-sensitive adhesive layer of the lower plate surface protective film is 70 to 100 parts by weight of the main polydimethylsiloxane; 10 to 40 parts by weight of MQ resin; And 100 to 150 parts by weight of a conventional solvent; Surface protective film comprising a pressure-sensitive adhesive composition comprising. The method of claim 5, wherein The adhesive composition is a surface protective film, characterized in that the addition of 1 to 5 parts by weight of an anchorage (anchorage) which is dimethylvinylsiloxane. The method of claim 5, wherein The pressure-sensitive adhesive composition is a surface protective film, characterized in that a crosslinking agent which is polymethylhydrogen siloxane is further added in 0.5 to 5 parts by weight. The method of claim 7, wherein The pressure-sensitive adhesive composition is a surface protective film, characterized in that the tin or platinum catalyst is further added in 0.5 to 2 parts by weight. The method according to any one of claims 5 to 8, The lower plate surface protective film is a base film; A primer layer formed on the base film; And the pressure-sensitive adhesive layer formed on the primer layer. The method of claim 9, The primer layer is a coating layer of a primer composition comprising 20 parts by weight of a main component of silane coupling agent, 1 to 10 parts by weight of a crosslinking agent of polyorganosiloxane, 1 to 5 parts by weight of a common catalyst, and 80 to 380 parts by weight of a common solvent. As Surface primer film, characterized in that the viscosity of the primer composition is 10 to 300cps. The method of claim 1, The pressure-sensitive adhesive layer of the top plate surface protection film is 100 parts by weight of the acrylic resin of the main body; 1 to 10 parts by weight of isocyanate curing agent; And 20 to 50 parts by weight of a common solvent; Surface protective film comprising a pressure-sensitive adhesive composition comprising.

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