KR101301941B1 - Surface protection film and optical component attached with the film - Google Patents

Abstract

The surface protective film is surface resistivity of 1 × 10 ¹³ [Ω / □] or more first pressure-sensitive adhesive layer with a surface resistivity of 1 × 10 ¹³ [Ω / □] is less than the second pressure-sensitive adhesive layer on one surface of a transparent base film of the present invention It is laminated | stacked and installed in this order.

Description

SURFACE PROTECTION FILM AND OPTICAL COMPONENT ATTACHED WITH THE FILM}

The present invention relates to a surface protective film bonded to a surface of an optical component (hereinafter referred to as an "optical film"), such as a polarizing plate, a retardation plate, and a lens film for a display. In detail, this invention relates to the surface protection film which is low in peeling electrification voltage when peeling a surface protection film, and has little time-lapse change of antistatic performance, and contamination to a to-be-adhered body, and the optical component using the same.

This application claims priority with respect to Japanese Patent Application No. 2011-112518 for which it applied on May 19, 2011, and uses the content here.

When manufacturing and conveying optical products, such as a display using optical films, such as a polarizing plate, a retardation plate, and a lens film for displays, a surface protection film is bonded to the surface of this optical film, and the optical film in a post process is carried out. Prevents contaminants and scratches on the surface. Moreover, the performance test and the external appearance test of an optical film may be performed in the state which bonded the surface protection film.

The surface protection film by a prior art typically provides the adhesive layer of a non-adhesive force on one side of a base film. An adhesive layer is a layer which has a role which bonds a surface protection film to the optical film. The use of the pressure-sensitive adhesive layer having a non-adhesive force is because the surface protection film, which has been used, can be peeled off and removed smoothly from the surface of the optical film, and the adhesive can be prevented from remaining on the surface of the optical film.

In the production process of image display apparatuses, such as a liquid crystal display panel, in recent years, peeling charging generate | occur | produces at the time of peeling and removing the surface protection film bonded on the surface of the optical film from the optical film. By this peeling charging, the phenomenon in which circuit components, such as a liquid crystal driver IC, is destroyed, and the orientation of a liquid crystal molecule may be lost.

On the other hand, in order to reduce the power consumption of a liquid crystal display panel, there exists a tendency to lower the drive voltage of the liquid crystal material used for a liquid crystal display panel. As a result, the breakdown voltage of the driver IC is also lowered, and in recent years, it has been required to be suppressed to the peeling electrification voltage within the range of +0.7 kV to -0.7 kV.

Accordingly, in order to prevent the occurrence of defects due to peeling charging generated when the surface protective film is peeled off from the adherend, a surface protective film using an adhesive layer having antistatic performance has been proposed.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 2005-131957) discloses a surface protective film using a pressure-sensitive adhesive composition composed of an alkyl trimethyl ammonium salt, a hydroxyl group-containing acrylic polymer, and a polyisocyanate.

In addition, Patent Document 2 (Japanese Patent Laid-Open No. 2005-330464) discloses an adhesive composition composed of an ionic liquid and an acrylic polymer having an acid value of 1.0 or less, and adhesive sheets using the same.

In addition, Patent Document 3 (Japanese Patent Laid-Open No. 2005-314476) discloses a pressure-sensitive adhesive composition composed of an acrylic polymer, a polyether polyol compound, an alkali metal salt treated with an anion adsorbent compound, and a surface protective film using the same.

In addition, Patent Document 4 (Japanese Patent Laid-Open No. 2006-152235) discloses an adhesive composition composed of an ionic liquid, an alkali metal salt, a polymer having a glass transition temperature of 0 ° C. or lower, and a surface protective film using the same.

As disclosed in Patent Literatures 1 to 4, in the case where an antistatic agent is added to an adhesive polymer, the thicker the pressure-sensitive adhesive layer is, the more the amount of the antistatic agent is transferred to the adherend as time passes. In an adherend such as an antiglare polarized plate or a glare polarized plate, it is difficult to visually identify contaminants that contaminate the surface of the adherend. On the other hand, in the AR (Anti Reflective) -treated polarizing plate having the antireflection layer on the surface of the polarizing plate, the contaminated state of the surface becomes very easy to see. Therefore, the contamination (degree of contamination to the surface) on the surface of the adherend is noticeable over time.

In order to exert peeling antistatic performance gradually over time, it is assumed to reduce content of the antistatic agent contained in the adhesive layer of a surface protection film. However, in this case, in the initial stage which bonded the surface protection film to the to-be-adhered body, there exists a tendency for peeling electrification voltage to become high, and both the antistatic performance of peeling electrification and the stability with time-lapse are difficult.

In addition, it is also assumed that the thickness of the pressure-sensitive adhesive layer is made thin for both antistatic performance of peeling charging and stability over time. In this case, however, it is difficult to adjust the adhesive force to a predetermined value. Moreover, in the to-be-adhered body which has an unevenness | corrugation on the surface of an optical film like an antiglare polarizing plate etc., a deformation | transformation of the adhesive layer of a surface protection film cannot follow a surface unevenness, and air bubbles mix in the uneven | corrugated part of the surface of an optical film.

The present invention has been devised in view of the above circumstances, and a surface protection film having a low peeling electrification voltage when the surface protection film is peeled off, and a small change in the antistatic performance over time and less contamination on the adherend, and an optical component bonded thereto It aims to provide.

In order to solve the said subject, this invention makes the adhesive layer of a surface protection film into the adhesive layer which consists of two layers by laminating | stacking and laminating | stacking the adhesive layers which have different surface resistivity. That is, two layers of a 1st adhesive layer with a relatively high surface resistivity and a 2nd adhesive layer with a relatively low surface resistivity compared with this 1st adhesive layer are laminated | stacked on one side of the base material of a surface protection film in order. Thereby, the antistatic agent is concentrated only on the surface layer of the adhesive layer which consists of two layers. Thus, while exhibiting a predetermined antistatic performance, and maintaining the layer height (total thickness of the pressure-sensitive adhesive layer consisting of two layers) of the pressure-sensitive adhesive layer to a certain thickness or more, deformation of the surface protective film against the uneven shape of the adherend Maintain followability.

In order to solve the said subject, this invention adopts the following structures.

A first aspect of the surface-protective film according to the present invention, the surface resistivity is 1 × 10 ¹³ [Ω / □] or greater is less than the first pressure-sensitive adhesive layer with a surface resistivity of 1 × 10 ¹³ [Ω / □] on one surface of the transparent substrate film The 2nd adhesive layer is laminated | stacked and installed in this order.

According to a second aspect of the present invention, in the surface protection film of the first aspect, the second pressure sensitive adhesive layer is selected from the group of antistatic agents selected from the group of antistatic agents including surfactants, ionic liquids, and alkali metal salts as antistatic agents. Include.

In the 3rd aspect which concerns on this invention, in the said surface protection film of a said 1st or 2nd aspect, the said 2nd adhesive layer uses (meth) acrylic-type polymer as a base polymer.

4th aspect which concerns on this invention WHEREIN: The ratio (A / B) of the thickness (A) of a 1st adhesive layer and the thickness (B) of a 2nd adhesive layer in the surface protection film of any one of said 1st-3rd form. ) Is in the range of 10/1 to 1/2. The 1st aspect of the optical component which concerns on this invention is the optical component which the surface protective film of any one of said 1st-4th bonded together.

The surface protection film of this invention uses a 2nd adhesive layer with a relatively low surface resistivity (less than 1 * 10 <^{13> (} ohm) / square) to the adhesive layer which directly contacts the optical film surfaces, such as a polarizing plate, a retardation plate, and a lens film. The peeling withstand voltage at the time of peeling is suppressed low. In addition, the surface protection film of this invention uses the 1st adhesive layer with a relatively high surface resistivity (1 * 10 <^{13> (} ohm) / square or more) provided between a base material and the 2nd adhesive layer with relatively low surface resistivity. By using this 1st adhesive layer, the time-dependent change of the bleed-out of an antistatic agent is suppressed, and stabilization of adhesive force and the followability of the surface protection film to the to-be-adhered body which have an uneven shape are ensured. As a result, the surface protection film of this invention has little time-lapse change of antistatic performance and contamination with a to-be-adhered body, the peeling withstand voltage at the time of peeling is low, and can reliably protect the surface of an optical component. As a result, the yield at the time of manufacturing an optical component can be improved.

1 is a sectional view showing a schematic configuration example of a surface protective film of the present invention.
2 is a cross-sectional view showing an embodiment of an optical component of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on embodiment of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the surface protection film of this invention. The surface protective film 5 is laminated on one surface of the transparent base film 1 with a first pressure sensitive adhesive layer 2 having a relatively high surface resistivity and a second pressure sensitive adhesive layer 3 having a relatively low surface resistivity in this order. have. Moreover, the peeling film 4 for protecting the adhesive face 8 is superimposed on the surface of the 2nd adhesive layer 3.

As the base film 1 used for the surface protection film of this invention, the plastic film which has transparency is used. Thereby, performance inspection and an external appearance inspection of an optical component can be performed with the surface protection film of this invention bonded together. As a plastic film used for the base film 1 used for the surface protection film of this invention, Preferably, a polyester film like polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, or polybutylene terephthalate is used. Moreover, if it is a plastic film which has required intensity | strength and optical aptitude, plastic films other than a polyester film can also be used. The base film 1 may be a film not stretched, or a film stretched in the uniaxial or biaxial direction. Moreover, the plastic film which controlled the angle of the axial direction formed according to draw ratio or crystallization of extending | stretching may be sufficient.

The thickness of the base film 1 is not specifically limited. However, it is preferable that it is about 12-100 micrometers, for example, and, as for the thickness of the base film 1 from a point of cost and ease of handling, it is more preferable that it is about 20-50 micrometers.

The base film 1 is a method for preventing contaminants from adhering to the surface 6 on the surface 6 opposite to the surface on which the first adhesive layer 2 having a relatively high surface resistivity is laminated, as necessary. You may provide a 5 layer, an antistatic layer, or the hard-coat layer which prevents a flaw. Alternatively, the surface 6 may be subjected to a simple surface treatment such as corona discharge treatment, atmospheric pressure plasma treatment, or anchor coat treatment instead of providing such a layer.

The first adhesive layer 2 having a relatively high surface resistivity is provided on the base film 1 side of the adhesive layer 7 composed of two layers, and has a surface resistivity of 1 × 10 ¹³ Ω / □ or more. to be. The adhesive composition used for the 1st adhesive layer 2 with a relatively high surface resistivity has the high adhesive force with the base film 1, the stability of adhesive force, and the 2nd adhesive layer 3 with relatively low surface resistivity. Known adhesive compositions can be used as long as the properties such as no adverse effects are satisfied.

As a specific adhesive composition of the 1st adhesive layer 2 with a relatively high surface resistivity, a rubber adhesive, an acrylic adhesive, or a urethane type adhesive etc. can be used.

A rubber adhesive is an adhesive which mix | blended a tackifier, a softener, anti-aging agent, a filler, etc. with elastomer, such as natural rubber or synthetic rubber. As needed, you may add a crosslinking agent to this rubber-based adhesive.

An acrylic adhesive is an adhesive which added the hardening | curing agent and the tackifier to the (meth) acrylic-type polymer as needed.

Examples of the (meth) acrylic polymer used in the pressure-sensitive adhesive composition of the first pressure-sensitive adhesive layer 2 having a relatively high surface resistivity include alkyl such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and isononyl acrylate. Main monomers consisting of (meth) acrylates (preferably alkyl (meth) acrylates having 4 or more carbon atoms in the alkyl group), and noses such as acrylonitrile, vinyl acetate, methyl methacrylate and ethyl acrylate. Monomers or polymers copolymerized with (meth) acrylic monomers having functional groups such as acrylic acid, methacrylic acid, hydroxy ethyl acrylate, hydroxy butyl acrylate, glycidyl methacrylate, and N-methylol methacrylamide are generally used. It can be mentioned as.

An isocyanate compound, an epoxy compound, a melamine compound, a metal chelate compound, etc. are mentioned as a hardening | curing agent.

As a tackifier, rosin type, coumarone indene type, terpene type, petroleum type, or phenol type etc. are mentioned.

As a urethane type adhesive, what changed the kind and composition ratio of a hard segment and a soft segment is mentioned.

As an adhesive composition of the 1st adhesive layer 2 with a relatively high surface resistivity, an acrylic adhesive is especially preferable at the point which is excellent in transparency, heat resistance, and durability, and the influence degree to the 2nd adhesive layer 3 is small.

The second pressure sensitive adhesive layer 3 having a relatively low surface resistivity is provided on the adherend side of the pressure sensitive adhesive layer 7 composed of two layers, and is used for bonding to the adherend, and the surface resistivity is 1 × 10 ¹³ Ω / □ It is an adhesive layer which has transparency below. This 2nd adhesive layer 3 mixes antistatic agent with base polymers, such as a (meth) acrylic-type polymer. It is preferable to consist of the adhesive composition which added the hardening | curing agent and the tackifier to the 2nd adhesive layer 3 as needed.

Examples of the (meth) acrylic polymer used in the pressure-sensitive adhesive composition of the second pressure-sensitive adhesive layer 3 having a relatively low surface resistivity include alkyl such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate and isononyl acrylate. Main monomers consisting of (meth) acrylates (preferably alkyl (meth) acrylates having 4 or more carbon atoms in the alkyl group), and noses such as acrylonitrile, vinyl acetate, methyl methacrylate and ethyl acrylate. The polymer which copolymerized the monomer or the (meth) acrylic-type monomer which has functional groups, such as acrylic acid, methacrylic acid, hydroxy ethyl acrylate, hydroxy butyl acrylate, glycidyl methacrylate, and N-methylol methacrylamide, is preferable. Is used. What is necessary is just to select a more suitable adhesive composition according to the characteristic of the required 2nd adhesive layer 3.

The antistatic agent is preferably one having good dispersibility or compatibility with respect to the (meth) acrylic polymer, and examples thereof include surfactants, ionic liquids, alkali metal salts, metal oxides, metal fine particles, conductive polymers, carbon or carbon nanotubes, and the like. . However, in consideration of transparency, affinity for the (meth) acrylic polymer, etc. of the second pressure sensitive adhesive layer 3 having a relatively low surface resistivity, the second pressure sensitive adhesive layer 3 may be a surfactant, an ionic liquid, or an antistatic agent. It is preferable to include the 1 type (s) or plural types chosen from the antistatic agent group which consists of alkali metal salts.

Examples of the surfactant include nonionic, cationic, anionic or amphoteric systems.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, glycerin fatty acid esters, and propylene glycol. Fatty acid esters or polyoxyalkylene-modified silicones;

Examples of the cationic surfactants include alkyltrimethyl ammonium salts, dialkyldimethyl ammonium salts, and alkylbenzyldimethyl ammonium salts.

Examples of the anionic surfactants include monoalkyl sulfates, alkyl polyoxyethylene sulfates, alkylbenzene sulfonates or monoalkyl phosphates.

Examples of amphoteric surfactants include alkyldimethylamine oxide and alkylcarboxybetaine.

Ionic liquids consist of anions and cations and are non-polymeric materials that are liquid at room temperature (eg 25 ° C). Examples of the cation moiety include cyclic amidine ions such as imidazolium ions, pyridinium ions, ammonium ions, sulfonium ions or phosphonium ions. As the anion ^{_{portion, C n H 2n +1 COO -}} , C n F 2n +1 COO -, NO 3 -, C n F 2n +1 SO 3 -, (C n F 2n +1 SO 2) 2 N -, (C n F ^{_{2n +1 SO 2) 3 C -}} , PO 4 2 -, AlCl 4 -, Al 2 Cl 7 -, ClO 4 -, BF 4 -, PF 6 - , and the like ^-, AsF ₆ ^- or SbF _6.

As an alkali metal salt, the metal salt etc. which consist of lithium, sodium, or potassium are mentioned. In order to stabilize an ionic substance, you may add the compound containing a polyoxy alkylene structure to this alkali metal salt.

In the pressure-sensitive adhesive composition of the second pressure-sensitive adhesive layer 3 having a relatively low surface resistivity, the amount of the antistatic agent added to the base polymer such as the (meth) acrylic polymer varies depending on the type of the antistatic agent and the degree of compatibility with the base polymer. Do. However, what is necessary is just to set the addition amount of this antistatic agent in consideration of surface resistivity, contamination with an adherend, or adhesive force.

In the adhesive layer 7 which consists of two layers, the ratio of the thickness A of the 1st adhesive layer 2 with a relatively high surface resistivity, and the thickness B of the 2nd adhesive layer 3 with a relatively low surface resistivity is shown. It is preferable that (A / B) exists in the range of 10/1-1/2.

On one side of the base film 1 of the surface protection film 5 of this invention, adhesive force and peeling voltage at the time of peeling a surface protection film are low, and it has the performances, such as a little change with the contaminant with respect to a to-be-adhered body with time. The pressure-sensitive adhesive layer is laminated.

When the thickness A of the first pressure sensitive adhesive layer 2 having a relatively high surface resistivity exceeds 10 times the thickness B of the second pressure sensitive adhesive layer 3 having a relatively low surface resistivity (that is, A / B> 10 / 1), when the total thickness T of the pressure-sensitive adhesive layer 7 composed of two layers is thin, the peeling electrification voltage at the time of peeling becomes high. On the other hand, when the total thickness T of the pressure-sensitive adhesive layer 7 composed of two layers is thick, the peeling electrification voltage at the time of peeling is suppressed. However, when the total thickness T of the adhesive layer 7 is thick, the adhesive force at the time of high-speed peeling becomes high too much, or the price competitiveness falls with the increase of the manufacturing cost of an adhesive layer.

When the thickness B of the second pressure sensitive adhesive layer 3 having a relatively low surface resistivity exceeds two times the thickness A of the first pressure sensitive adhesive layer 2 having a relatively high surface resistivity (that is, A / B <1 / 2), when the total thickness T of the adhesive layer 7 which consists of two layers is thin, it becomes difficult to adjust adhesive force to a predetermined value. Moreover, in the to-be-adhered body which has an uneven | corrugated shape on the surface, such as an antiglare polarizing plate, the deformation | transformation of the adhesive layer 7 which consists of two layers of the surface protection film 5 does not follow the uneven | corrugated shape of the surface, and the uneven | corrugated shape of the surface There is a possibility that bubbles are mixed in the wealth. On the other hand, when the total thickness T of the adhesive layer 7 which consists of two layers is thick, there exists a possibility that the contamination with respect to the surface of the optical film which is a to-be-adhered body may worsen over time.

The total thickness T of the pressure-sensitive adhesive layer 7 consisting of two layers is not particularly limited. However, the total thickness T of the adhesive layer 7 which consists of two layers is about 5-40 micrometers, for example, It is preferable that it is about 10-30 micrometers.

In the surface protection film 5 of this invention, the 2nd adhesive layer 3 which consists of a microadhesive layer which has the adhesiveness of the hardness whose peeling strength with respect to a to-be-adhered body surface is about 0.03-0.3 N / 25 mm. ) Is preferably disposed as the pressure-sensitive adhesive layer for adherends.

What is necessary is just to perform the method of laminating | stacking the 1st adhesive layer 2 with a relatively high surface resistivity, and the 2nd adhesive layer 3 with a relatively low surface resistivity on one surface of the base film 1 by a well-known method, It is not specifically limited. Specifically, there are the following methods (1) to (3), but any method may be used.

(1) The lamination | stacking of the 1st adhesive layer 2 with respect to the base film 1 is completed by apply | coating and drying the 1st adhesive layer 2 with a relatively high surface resistivity on one surface of the base film 1. . Then, the 1st adhesive layer 2 is apply | coated and dried by apply | coating and drying the 2nd adhesive layer 3 with relatively low surface resistivity on the surface of the 1st adhesive layer 2 which is opposite to the surface which the base film 1 contact | connects. Lamination | stacking of the 2nd adhesive layer 3 with respect to) is completed.

(2) The 1st adhesive layer 2 with a relatively high surface resistivity is apply | coated to one surface of the base film 1. Before this 1st adhesive layer 2 dries, the 2nd adhesive layer 3 with relatively low surface resistivity is apply | coated on the surface of the 1st adhesive layer 2 opposite to the surface which the base film 1 contact | connects. do. Thereafter, the first pressure sensitive adhesive layer 2 and the second pressure sensitive adhesive layer 3 are simultaneously dried.

(3) The first adhesive layer 2 having a relatively high surface resistivity was applied to one surface of the base film 1 and dried, and the second adhesive having a relatively low surface resistivity on one surface of the release film 4. The layer 3 was apply | coated and dried, and each is produced. The 1st adhesive layer 2 and the 2nd adhesive layer 3 in both these are bonded.

The method of forming the adhesive layer which consists of two layers on one surface of the base film 1 can be performed by a well-known method. Specifically, coating methods such as reverse coating, comma coating, gravure coating, slot die coating, Mayer bar coating, and air knife coating can be adopted. In the adhesive sheet formed by laminating | stacking the 1st adhesive layer 2 and the 2nd adhesive layer 3 in order to the base film 1, the surface of the 2nd adhesive layer 3 is protected by the peeling film 4 It is common to do However, the adhesive sheet which laminated | stacked the 1st adhesive layer 2 and the 2nd adhesive layer 3 in order to the base film 1 without using the peeling film 4 as needed was the form of the form which wound up. It is also possible to realize the product.

The configuration of the release film 4 is not particularly limited. The peeling process may be performed to the surface of resin films, such as a polyester film, using peeling agents, such as a silicone type peeling agent.

By laminating | stacking the 2nd adhesive layer 3 containing an antistatic agent on one surface of the base film 1 of the surface protection film 5 which has the said structure, peeling charge voltage at the time of surface protection film peeling can be suppressed low. Can be. Antistatic performance so that peeling electrification voltage at the time of peeling from the optical film which is an adherend is suppressed to + 0.7kV--0.7kV, Preferably it is + 0.5kV--0.5kV, More preferably, + 0.1kV--0.1kV It is particularly desirable to realize this.

This peeling electrification voltage can be adjusted according to the kind, content, etc. of the antistatic agent contained in the 2nd adhesive layer 3.

2 is a schematic configuration diagram showing an example of the optical component 10 of the present invention.

This optical component 10 bonds the said surface protection film 5 to the surface of the optical film 11 via the 2nd adhesive layer 3 laminated | stacked on the 1st adhesive layer 2. As the optical film 11, a polarizing plate, a retardation plate, a lens film, a polarizing plate combined with a retardation plate, a polarizing plate combined with a lens film, etc. are mentioned. Such an optical film 11 enters into a liquid crystal display device such as a liquid crystal display panel, an optical system device of various instruments, and the like. In addition, the optical film 11 includes a plate, a sheet, a film, or the like regardless of its thickness. Moreover, the surface protection film of this invention is applicable also to manufacturing processes, such as an antireflection film, a hard-coat film, and a transparent conductive film for touch panels.

According to the optical component 10 of the present invention, when the surface protection film 5 is used and peeled off, the peeling electrification voltage of the optical film 11 is sufficiently reduced. As a result, there is no possibility of electrically shorting and destroying circuit components, such as a driver IC, a TFT element, and a gate line drive circuit, and can maintain the reliability of display apparatuses, such as a liquid crystal display panel.

(Example)

Next, an Example is given and this invention is demonstrated in detail.

(Production of the surface protective film of Example 1)

3 parts by weight of an isocyanate curing agent as a curing agent to 100 parts by weight of an acrylic base polymer composed of 2-ethylhexyl acrylate and a hydroxyl group-containing acrylic monomer for forming the first pressure-sensitive adhesive layer having a surface resistivity of 1 × 10 ¹³ [Ω / □] or more. The compounded adhesive composition (a) was produced.

On the other hand, alkyltrimethyl ammonium chloride which is an alkyltrimethyl ammonium salt as an antistatic agent to an adhesive composition (a) for formation of the 2nd adhesive layer whose surface resistivity is less than 1x10 <^13> (ohm / square) (Kao Corporation make, brand name: Electrostripper QN) ) Was mixed at a ratio of 1 part by weight based on 100 parts by weight of the pressure-sensitive adhesive composition (a) to prepare an pressure-sensitive adhesive composition (b). The surface resistivity of the pressure-sensitive adhesive composition (a) measured after applying and drying the pressure-sensitive adhesive composition (a) to one side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 38 μm so that the coating thickness after drying was 20 μm was 1.5. X10 ¹⁴ [Ω / □]. On the other hand, the surface resistivity of the adhesive composition (b) measured after apply | coating and drying an adhesive composition (b) so that the coating thickness after drying may be set to 20 micrometers on one side of the biaxially-stretched polyethylene terephthalate (PET) film of 38 micrometers in thickness. Was 7.5 × 10 ¹² [Ω / □].

Next, in order to produce the surface protection film of Example 1, the coating thickness after drying an adhesive composition (a) on one side of the 38-micrometer-thick biaxially-stretched polyethylene terephthalate (PET) film used as a base film is 15 It applied and laminated so that it might become micrometer. Then, the adhesive composition (b) was apply | coated and laminated | stacked on the application surface of the adhesive composition (a) so that the application thickness after drying might be 5 micrometers (total thickness of two adhesive layers is 20 micrometers). Thereafter, two pressure-sensitive adhesive layers were dried and cured in a hot air circulation oven. Then, in order to protect the surface of two adhesive layers, the polyethylene terephthalate (PET) film (peel film) which performed the peeling process with the silicone type peeling agent was bonded together, and the adhesive sheet was produced. The obtained adhesive sheet was aged at 40 degreeC for 3 days, and the surface protection film of Example 1 was obtained.

(Production of surface protective film of Example 2)

The adhesive composition (a) was laminated | stacked on one surface of the base film so that the coating thickness after drying might be set to 17 micrometers, and the adhesive composition (b) was laminated | stacked so that the coating thickness after drying might be set to 3 micrometers. Other than that was carried out similarly to Example 1, and obtained the surface protection film of Example 2.

(Production of surface protective film of Example 3)

The adhesive composition (a) and the adhesive composition (b) were laminated | stacked on one side of the base film so that the application thickness after drying might be set to 10 micrometers. Other than that was carried out similarly to Example 1, and obtained the surface protection film of Example 3.

(Production of the surface protection film of the comparative example 1)

Without using the adhesive composition (b) on one side of the base film, only the adhesive composition (a) was laminated so that the coating thickness after drying might be 20 micrometers. Other than that was carried out similarly to Example 1, and obtained the surface protection film of the comparative example 1.

(Production of the surface protection film of the comparative example 2)

Without using an adhesive composition (a) on one side of a base film, only the adhesive composition (b) was laminated | stacked so that the application thickness after drying might be set to 20 micrometers. Other than that was carried out similarly to Example 1, and obtained the surface protection film of the comparative example 2.

(Production of the surface protection film of the comparative example 3)

The adhesive composition (a) was laminated | stacked on one surface of the base film so that the coating thickness after drying might be set to 19 micrometers, and the adhesive composition (b) was laminated | stacked so that the coating thickness after drying might be set to 1 micrometer. Other than that was carried out similarly to Example 1, and obtained the surface protection film of the comparative example 3.

(Production of the surface protection film of the comparative example 4)

The adhesive composition (a) was laminated | stacked on one surface of the base film so that the application thickness after drying might be set to 5 micrometers, and the adhesive composition (b) was laminated | stacked so that the application thickness after drying might be set to 15 micrometers. Other than that was carried out similarly to Example 1, and obtained the surface protection film of the comparative example 4.

(Preparation of surface protective film of Example 4)

1.0 weight part of lithium perchlorates which are lithium metal salts were added to 100 weight part of adhesive composition (a) as an antistatic agent, and the adhesive composition (c) was produced. After applying and drying the adhesive composition (c) to one side of the biaxially stretched polyethylene terephthalate (PET) film having a thickness of 38 μm so that the coating thickness after drying was 20 μm, the surface resistivity of the measured adhesive composition (c) was It was 2.8x10 <^11> [ohm / square].

Next, in order to produce the surface protection film of Example 4, the adhesive composition (a) is laminated | stacked on one surface of a base film so that the application thickness after drying may be set to 15 micrometers, and the application thickness after drying the adhesive composition (c) is 5 It was laminated so as to be a 탆. Others were carried out similarly to Example 1, and produced the surface protection film of Example 4.

(Production of surface protective film of Example 5)

The adhesive composition (a) was laminated | stacked on one surface of the base film so that the coating thickness after drying might be 18 micrometers, and the adhesive composition (c) was laminated | stacked so that the coating thickness after drying might be 2 micrometers. Other than that was carried out similarly to Example 4, and obtained the surface protection film of Example 5.

(Production of the surface protection film of the comparative example 5)

The adhesive composition (a) was laminated | stacked on one surface of the base film so that the coating thickness after drying might be set to 19 micrometers, and the adhesive composition (c) was laminated | stacked so that the coating thickness after drying might be set to 1 micrometer. Other than that was carried out similarly to Example 4, and obtained the surface protection film of the comparative example 5.

(Production of the surface protection film of the comparative example 6)

2 parts by weight of lithium perchlorate, which is a lithium metal salt, was added to 100 parts by weight of the pressure-sensitive adhesive composition (a) to prepare an pressure-sensitive adhesive composition (d). The surface resistivity measured after apply | coating and drying adhesive composition (d) so that the application thickness after drying may be set to 20 micrometers on one side of the biaxially-stretched polyethylene terephthalate (PET) film of 38 micrometers in thickness was 6.8x10 <^10> [(ohm / s) □].

Next, in order to produce the surface protection film of the comparative example 6, the adhesive composition (a) is laminated | stacked on one surface of a base film so that the application thickness after drying may be set to 19 micrometers, and the application thickness after drying the adhesive composition (d) is 1 It was laminated so as to be a 탆. Other than that was carried out similarly to Example 4, and obtained the surface protection film of the comparative example 6.

(Production of the surface protection film of the comparative example 7)

Without using an adhesive composition (a) on one side of a base film, only the adhesive composition (c) was laminated | stacked so that the application thickness after drying might be set to 5 micrometers. Other than that was carried out similarly to Example 4, and obtained the surface protection film of the comparative example 7.

(Production of surface protective film of Example 6)

To 100 parts by weight of the pressure-sensitive adhesive composition (a), 5 parts by weight of an ionic liquid (3M manufactured, product number: FC-4400) was added as an antistatic agent to prepare a pressure-sensitive adhesive composition (e). The surface resistivity measured after apply | coating and drying adhesive composition (e) so that the application thickness after drying may be set to 20 micrometers on one side of the biaxially-stretched polyethylene terephthalate (PET) film of 38 micrometers in thickness was 6.3 * 10 <^12> (ohm / □].

Next, in order to produce the surface protection film of Example 6, the adhesive composition (a) is laminated | stacked on one surface of a base film so that the application thickness after drying may be 15 micrometers, and the application thickness after drying the adhesive composition (e) is 5 It was laminated so as to be a 탆. Other than that was carried out similarly to Example 1, and produced the surface protection film of Example 6.

Hereinafter, the method and the result of an evaluation test are shown.

(Measurement Method of Adhesion of Surface Protective Film)

The glare polarizing plate is bonded to one side of a glass plate through an adhesive layer using a bonding machine. Then, after bonding what cut the surface protection film into 25 mm width on the surface of a polarizing plate, it is stored for 1 day in 23 degreeC and 50% RH environment. Then, the peeling strength at the time of peeling a surface protection film in 180 degree direction at the peeling speed of 300 mm / min using a tensile tester was measured, and this was made into the adhesive force of a surface protection film.

(Measuring method of peeling electrification voltage of surface protection film)

The glare polarizing plate is bonded to one side of a glass plate through an adhesive layer using a bonding machine. Then, what cut the surface protection film into 25 mm width was bonded to the surface of a polarizing plate. Then, the surface potential of the surface of the polarizing plate was measured every 10 kV using a surface electrometer (manufactured by Keyence Co., Ltd.) while peeling the surface protective film at a speed of 40 m per minute using a high speed peel tester (manufactured by Tester Industries). At this time, the maximum value of the absolute value of surface potential was made into peeling electrification voltage.

(Method for evaluating contamination on the surface of the adherend of the surface protective film)

The polarizing plate which gave the low reflection surface treatment on one surface of the glass plate is bonded through an adhesive layer using a bonding machine. Thereafter, the surface protective film was bonded to the surface of the polarizing plate using a bonding machine, and then it was stored over a period of 3 days and 30 days in an environment of 23 ° C. and 50% RH. Thereafter, the surface protective film is peeled off and the contamination state on the surface of the polarizing plate is visually observed.

The contamination on the surface of the adherend was evaluated as "(circle)" when there was no contamination on the surface of the polarizing plate, "△" as when there was some contamination, and "x" when there was contamination.

(Evaluation method of bonding appearance of surface protection film)

As a to-be-adhered body, a surface protection film was bonded to the surface of a to-be-adhered body using the bonding machine using the glare polarizing plate and the low reflection antiglare polarizing plate. The joint appearance at that time is visually observed.

"*" Evaluated the case where the external appearance of the surface protection film with respect to a to-be-adhered body is favorable, and the case where the external appearance of the bonding was poor was "x".

Table 1 shows the measurement results for the samples of Examples 1 to 6 and Comparative Examples 1 to 7. In Table 1, the thickness of a 1st adhesive layer is described with (A) and the thickness of a 2nd adhesive layer with (B).

The following can be confirmed from the measurement result shown in Table 1.

From the measurement result of Examples 1-6, the surface protection film of this invention is equipped with moderate adhesive force, there is no contamination on the surface of a to-be-adhered body even after 30 days pass, and the surface protection film with low peeling electrification voltage when peeling a surface protection film. It is.

On the other hand, in Comparative Example 1 using only the first pressure sensitive adhesive layer having a relatively high surface resistivity, since the peeling electrification voltage when peeling the surface protection film is high, the breakage of the driver IC and the There is a possibility of causing loss of orientation. In Comparative Example 2 using only the second pressure-sensitive adhesive layer having a relatively low surface resistivity, since contamination occurs on the surface of the adherend after 30 days, contamination may proceed to the surface of the adherend over time.

Moreover, in the adhesive layer which consists of two layers of a 1st adhesive layer with a relatively high surface resistivity, and a 2nd adhesive layer with a relatively low surface resistivity, when the balance of the thickness of two adhesive layers falls, a surface protection film is peeled off. There exists a possibility that the peeling electrification voltage at the time of raising, and contamination to the surface of a to-be-adhered body may advance over time (Comparative Examples 3-6).

In Comparative Example 7, the surface resistivity is relatively large so that the thickness of the pressure-sensitive adhesive layer is within a range where the contamination of the surface of the adherend is not a problem, ignoring the lamination of the total thickness of the pressure-sensitive adhesive layer to 20 µm. Only the low 2nd adhesive layer was laminated | stacked on the surface of a base film, and the surface protection film was produced. However, this surface protection film was low in adhesive force and could not be bonded cleanly to the surface of a to-be-adhered body.

That is, the surface protection film of this invention is applied to the surface of optical films, optical components, etc., for example in manufacturing processes, such as optical films, such as a polarizing plate, retardation plate, and a lens film, and optical components, such as a display using the same. By bonding, the surface can be protected reliably. Moreover, the surface protection film of this invention is applicable also to manufacturing processes, such as an antireflection film, a hard-coat film, and a transparent conductive film for touch panels.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to these examples. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the invention. That is, this invention is not limited only to the above-mentioned description, It is clear that various changes or modifications can be assumed in the range as described in this specification, and those of course also belong to the technical scope of this invention.

Claims (10)

The surface in which the first adhesive layer having a surface resistivity of 1 × 10 ¹³ [Ω / □] or more and the second adhesive layer having a surface resistivity of less than 1 × 10 ¹³ [Ω / □] are laminated in this order on one surface of the transparent base film. Protective film. The method of claim 1,
The surface protection film in which the said 2nd adhesive layer contains 1 type (s) or multiple types chosen from the antistatic agent group which consists of surfactant, an ionic liquid, and alkali metal salt. The method of claim 1,
The surface protection film in which the said 2nd adhesive layer uses the (meth) acrylic-type polymer as a base polymer. 3. The method of claim 2,
The surface protection film in which the said 2nd adhesive layer uses the (meth) acrylic-type polymer as a base polymer. The method according to any one of claims 1 to 4,
The surface protection film in which the ratio (A / B) of the thickness (A) of a 1st adhesive layer and the thickness (B) of a 2nd adhesive layer is in the range of 10/1-1/2. The optical component to which the surface protection film of Claim 1 was bonded. The optical component to which the surface protection film of Claim 2 was bonded. The optical component to which the surface protection film of Claim 3 was bonded. The optical component to which the surface protection film of Claim 4 was bonded. The optical component to which the surface protection film of Claim 5 was bonded.

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