JP2011042779A - Pressure-sensitive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape having both of adhesiveness with and releasability from an uneven-shaped member, causing no deformation of the uneven shape even when protected members are laminated and deformed, preventing damage of a base material layer in the pressure-sensitive adhesive tape, and achieving both of low haze property excellent in transparency and such high surface roughness that foreign matter such as a fish eye is hardly observed without fluctuations in mechanical properties of the entire pressure-sensitive adhesive tape. <P>SOLUTION: The pressure-sensitive adhesive tape includes a fine unevenness-erasing layer 3, a roughness-expressing layer 2, a base material layer 1, a first pressure-sensitive adhesive layer 21, and a second pressure-sensitive adhesive layer 22 in this order. The base material layer contains a thermoplastic resin. The roughness-expressing layer contains resin components. The fine unevenness-erasing layer contains a thermoplastic resin. An MFR of the thermoplastic resin contained in the fine unevenness-erasing layer is higher than that of any of the resin components contained in the roughness-expressing layer. The haze value of the laminate is 30% or less. A storage elastic modulus of the adhesive constituting the first pressure-sensitive adhesive layer is higher than that of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an adhesive tape. More specifically, the present invention relates to an adhesive tape that can effectively protect the uneven surface of a member having an uneven surface.

  In general, in order to protect the surface of various adherends, an adhesive tape in which an adhesive layer is laminated on one surface of a film-like base material layer is widely used.

  On the other hand, there are many members having irregularities formed on the surface for the purpose of imparting design properties, handling properties, optical functionality, and the like. In such a member having irregularities formed on the surface, there is a problem that dust adheres to the irregular portions or the convex portions are damaged. In order to prevent such a problem, the above adhesive tape is used.

  Such an adhesive tape requires an adhesive force that does not peel off while protecting a member having irregularities formed on the surface. For that purpose, it is necessary to use a flexible adhesive for the adhesive layer to provide an adhesive tape having high adhesive force. However, when a soft adhesive is used for the adhesive layer, the uneven top of the member with unevenness formed on the surface of the adherend penetrates the adhesive layer and reaches the base material layer, which deforms the uneven top. Problem arises.

  On the other hand, if the adhesive force between the member having unevenness on the surface and the adhesive tape is too strong, there arises a problem that smooth peeling cannot be performed when the adhesive tape is peeled from the member having unevenness on the surface.

  Therefore, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape used for protecting the member having irregularities formed on the surface needs to have contradictory performances of adhesion and releasability, and the top of the irregularity is the pressure-sensitive adhesive tape when protected. It is also necessary to have a hardness that does not reach the base material layer.

  As a pressure-sensitive adhesive tape having a special pressure-sensitive adhesive layer, a pressure-sensitive adhesive tape using a pressure-sensitive adhesive layer having a styrene-based elastomer as a main component and having a thickness of 10 μm or less is disclosed (for example, see Patent Document 1).

  However, in the pressure-sensitive adhesive tape disclosed in Patent Document 1, when used for protecting the surface of a member having irregularities formed on the surface, the irregularities top penetrates the adhesive layer and reaches the base material layer, which deforms the irregularities top. The problem of letting it occur. Moreover, in the adhesive tape currently disclosed by patent document 1, depending on the selection of the material, there is a problem that it naturally peels off from the adherend without having sufficient adhesive force, and the adhesive tape is too strong to adhere. There arises a problem that smooth peeling from the body is not possible.

  In general, in order to protect the surface of various adherends, a surface protective film in which an adhesive layer is laminated on one surface of a film-like base material layer is widely used.

  On the other hand, prism sheets having a plurality of triangular prisms fixed on the sheet surface are used in various optical devices. In such a prism sheet, there is a problem that dust adheres to the lens surface (prism surface) or the lens portion (prism portion) is damaged. In order to prevent such a problem, the above surface protective film is used.

  The surface protective film that protects the surface of the prism sheet needs to have a stable adhesive force that does not peel during protection, and can be smoothly peeled off when it is peeled off because protection is no longer necessary. Further, when protecting the prism sheet with such a surface protective film, it is necessary to prevent an optically adverse effect on the precisely formed prism pattern.

  In general, rubber-based pressure-sensitive adhesives are generally used as pressure-sensitive adhesives in surface protection films for optical members such as prism sheets (see Patent Document 2).

  On the other hand, the prism sheet to which the surface protective film is attached is transported between processes in a laminated state, a long-rolled state, or the like. When the prism sheets are laminated in this way, the lens portion (prism portion) of the prism sheet may bite deeply into the surface protective film in an uneven manner due to the weight of the prism sheet. If unevenness (push marks) occurs in the appearance of the prism sheet to which the surface protective film is attached in this manner, it becomes difficult to perform an appearance inspection of the prism sheet with the surface protective film attached.

  Moreover, generally, an adhesive tape is adjusted to the haze value and surface roughness according to the objective (for example, external appearance adjustment). As a method for adjusting the haze value and the surface roughness, a T-die extrusion touch roll molding method, that is, a molten resin extruded with a T-die is brought into contact with a metal roll having an uneven pattern, and the uneven pattern is transferred to the surface of the resin. The method of making it known is known (for example, refer to Patent Documents 3 and 4).

  However, in the T-die extrusion touch roll molding method, if high-speed molding is performed, there is a problem of processing failure such that the molten resin is wound around the metal roll due to insufficient cooling of the resin, or the uneven pattern of the metal roll is sufficiently transferred to the resin. The problem that it is not done arises.

  Furthermore, in the T-die extrusion touch roll molding method, it is common for the surface of the touch roll rubber to be uneven for the purpose of improving the peelability of the molded product, and this unevenness affects the haze value of the molded product. Therefore, there arises a problem that it is difficult to obtain a molded product having a desired haze value (particularly, a medium / low haze value).

  As a method for adjusting the haze value and the surface roughness, in addition to the T-die extrusion touch roll molding method, there are a T-die air knife molding method, an inflation air cooling molding method, and the like. However, since these methods form irregularities on the surface of the molded product only by flow deformation from the time of melting the resin to the time of cooling and solidification, it is difficult to form precise irregularities on the surface of the molded product.

  Even during air-cooling, the haze value is adjusted by intentionally forming a sea-island phase-separated structure using two or more components that are not compatible with each other as the resin for forming the surface region of the adhesive tape. Has been tried. However, in order to control the sea-island structure of the entire surface area of the adhesive tape and adjust the haze value and surface roughness, it is necessary to ensure the thickness of the surface area of the adhesive tape accordingly, and the adhesive tape will be made thinner. Have difficulty. Moreover, it is necessary to adjust the composition of the material used for formation of the surface area | region of an adhesive tape each time with a desired haze value and surface roughness. As a result, with the adjustment of the haze value and the surface roughness, the mechanical properties of the entire adhesive tape vary greatly. For this reason, it is difficult to independently adjust the mechanical properties of the entire pressure-sensitive adhesive tape and the haze value and surface roughness of the pressure-sensitive adhesive tape.

  In addition, the pressure-sensitive adhesive tape used as a process material such as a protective film is required to be a low-haze film in order to perform an appearance inspection while protecting an object. However, if there is a foreign matter such as fish eye in the film or a foreign matter mixed at the time of bonding, the low-haze film is visually recognized as an appearance defect. For this reason, it is conceivable that the surface roughness of the film is intentionally increased (that is, roughened) so that the film cannot be visually observed.

  However, in general, the height of the haze of the film and the size of the surface roughness are approximately proportional. For this reason, if the surface roughness is increased, the haze increases and the permeability decreases, which causes a problem that the appearance inspection cannot be performed.

JP 2007-332329 A JP-A-11-181370 JP 2003-181962 A JP 2004-149639 A

The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is an adhesive tape capable of protecting the uneven surface of a member having unevenness on the surface, It has both sufficient adhesiveness and sufficient peelability, and when the member protected by the adhesive tape is deformed by lamination or long winding, the uneven shape is not deformed, Large surface that does not damage the base material layer in the adhesive tape, and does not fluctuate the mechanical properties of the entire adhesive tape. An object of the present invention is to provide an adhesive tape that is adjusted so as to be compatible with roughness.
In addition, when a prism sheet having a plurality of triangular prisms fixed on the surface is used as a member having irregularities on the surface, it functions as a surface protective film that can effectively protect the lens surface. A prism sheet that has both sufficient adhesiveness to the sheet and sufficient peelability, and has the adhesive tape applied when the prism sheet protected by the adhesive tape is in a state of lamination or long winding. It is in providing the adhesive tape which can suppress that a nonuniformity (press mark) arises in the external appearance of this.

The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a laminate (I), a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer having a base material layer, a roughness developing layer, and a fine unevenness erasing layer in this order. , A fine unevenness eliminating layer, a roughness developing layer, a base material layer, a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer in this order, the base material layer containing a thermoplastic resin, And at least one resin component (A) selected from polyethylene, ethylene-vinyl acetate copolymer, propylene-based polymer, and olefin-based thermoplastic elastomer, and the fine unevenness erasing layer comprises the thermoplastic resin (B). And the arithmetic average surface roughness Ra of the surface of the fine unevenness erasing layer side is 1.0 μm to 3.0 μm, the haze value of the laminate (I) is 30% or less, and the first pressure-sensitive adhesive layer The storage elastic modulus is higher than the storage elastic modulus of the second pressure-sensitive adhesive layer.
In a preferred embodiment, the storage elastic modulus of the first pressure-sensitive adhesive layer is 1.0 × 10 ⁶ Pa or more and less than 1.0 × 10 ⁹ Pa at a frequency of 10 Hz and 23 ° C.
In a preferred embodiment, the storage elastic modulus of the second pressure-sensitive adhesive layer is 1.0 × 10 ³ Pa or more and less than 1.0 × 10 ⁶ Pa at a frequency of 10 Hz and 23 ° C.
In preferable embodiment, the thickness of the said roughness expression layer is 2 micrometers-10 micrometers.
In preferable embodiment, the thickness of the said fine uneven | corrugated erase layer is 1 micrometer-10 micrometers.
In a preferred embodiment, the roughness developing layer has two or more melting temperatures Tm in differential scanning calorimetry.
In preferable embodiment, the said roughness expression layer contains at least 1 sort (s) chosen from a propylene type polymer and an olefin type thermoplastic elastomer.
In a preferred embodiment, the fine unevenness erasing layer has a long-chain alkyl release agent.
In preferable embodiment, the adhesive which comprises the said 1st adhesive layer is a thermoplastic adhesive, and the adhesive which comprises the said 2nd adhesive layer is a thermoplastic adhesive.
In a preferred embodiment, the adhesive tape of the present invention has a haze value of 30% or less.
In preferable embodiment, the adhesive tape of this invention is a surface protection film for prism sheets.

According to the present invention, there is provided an adhesive tape capable of protecting the uneven surface of a member having unevenness on the surface, which has both sufficient adhesiveness to the member and sufficient peelability, and the adhesive tape. Even when the member protected by the tape is deformed by laminating or long winding, the uneven shape is not deformed, and the base material layer in the adhesive tape is not damaged. Without changing the mechanical properties, it is possible to provide adhesive tapes adjusted to achieve both low haze with excellent permeability and large surface roughness that makes it difficult to see foreign objects such as fish eyes. It becomes.
In addition, when a prism sheet having a plurality of triangular prisms fixed on the surface is used as a member having irregularities on the surface, it functions as a surface protective film that can effectively protect the lens surface. A prism sheet that has both sufficient adhesiveness to the sheet and sufficient peelability, and has the adhesive tape applied when the prism sheet protected by the adhesive tape is in a state of lamination or long winding. It becomes possible to provide a pressure-sensitive adhesive tape that can suppress the occurrence of unevenness (push marks) in the appearance.

It is a schematic sectional drawing of the adhesive tape by preferable embodiment of this invention.

A. Adhesive tape The adhesive tape of this invention has the laminated body (I) which has a base material layer, a roughness expression layer, and a fine unevenness | corrugation elimination layer in this order, a 1st adhesive layer, and a 2nd adhesive layer. The base material layer side of the laminate (I) is disposed on the first pressure-sensitive adhesive layer side. Specifically, the pressure-sensitive adhesive tape of the present invention has a fine unevenness erasing layer, a roughness developing layer, a base material layer, a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer in this order. FIG. 1 is a schematic cross-sectional view of an adhesive tape according to a preferred embodiment of the present invention. The pressure-sensitive adhesive tape 100 includes a substrate layer 1, a roughness developing layer 2 disposed on one side of the substrate layer 1, and fine irregularities disposed on the opposite side of the roughness developing layer 2 to the substrate 1. The first pressure-sensitive adhesive layer 21 disposed on the opposite side of the erasing layer and the roughness developing layer layer 2 of the base material layer 1, and the first pressure-sensitive adhesive layer 21 disposed on the opposite side of the base material layer 1. A second pressure-sensitive adhesive layer 22 is provided. The pressure-sensitive adhesive tape of the present invention may further have any appropriate other layer as necessary (not shown).

  The thickness of the pressure-sensitive adhesive tape of the present invention can be set to any appropriate thickness depending on the application. Typically, it is 15 μm to 450 μm. The haze value of the pressure-sensitive adhesive tape of the present invention is preferably 30% or less, more preferably 25% or less, still more preferably 22% or less, and particularly preferably 20% or less. In view of the object of the present invention, the lower limit of the haze value of the pressure-sensitive adhesive tape of the present invention is preferably as low as possible, and ideally 0%. If the haze value of an adhesive tape is such a range, the said adhesive tape can have the low haze property excellent in the permeability | transmittance. The haze value can be measured by a method according to JISK7136.

A-1. Laminate (I)
The laminated body (I) in this invention has a base material layer, a roughness expression layer, and a fine unevenness | corrugation elimination layer in this order.

  The thickness of the laminate (I) in the present invention can be set to any appropriate thickness depending on the application. Preferably they are 10 micrometers-200 micrometers, More preferably, they are 10 micrometers-180 micrometers, More preferably, they are 12 micrometers-170 micrometers.

  In the laminate (I) of the present invention, the arithmetic average surface roughness Ra of the surface on the fine unevenness erasing layer side is 1.0 μm to 3.0 μm, more preferably 1.05 μm to 2.9 μm, Preferably they are 1.1 micrometers-2.8 micrometers. When the arithmetic average surface roughness Ra on the surface of the fine concavo-convex erasure layer is within such a range, the surface roughness can be made large enough that it is difficult to visually recognize foreign matters such as fish eyes.

  The haze value of the laminate (I) in the present invention is 30% or less, more preferably 25% or less, still more preferably 22% or less, and particularly preferably 20% or less. In view of the object of the present invention, the lower limit of the haze value of the laminate (I) in the present invention is preferably as low as possible, and ideally 0%. When the haze value of the laminate (I) is within such a range, the laminate (I) can have low haze properties with excellent permeability. The haze value can be measured by a method according to JISK7136.

A-1-1. Base material layer Arbitrary appropriate thickness can be employ | adopted for the thickness of the said base material layer according to a use. The thickness of the base material layer is preferably 10 μm to 150 μm, and more preferably 20 μm to 100 μm.

  As the haze value of the base material layer, any appropriate value can be adopted as long as the haze value of the laminate (I) in the present invention is 30% or less.

  The base material layer includes a thermoplastic resin. Any appropriate resin can be adopted as the thermoplastic resin as long as the film can be formed by melt extrusion. Examples of the thermoplastic resin include polyolefin resins such as propylene-based polymers, polyethylene, olefin-based thermoplastic elastomers (TPO), and modified products thereof; α-olefins and vinyl compounds (for example, vinyl acetate, (meth) acrylic acid esters). Polyamide; Polyester; Polycarbonate; Polyurethane; Polyvinyl chloride; Examples of the propylene-based polymer include homopolypropylene, block polypropylene, and random polypropylene.

  When homopolypropylene is used as the thermoplastic resin, the structure of the homopolypropylene may be isotactic, atactic, or syndiotactic.

  When polyethylene is used as the thermoplastic resin, the polyethylene may be any of low density polyethylene, medium density polyethylene, and high density polyethylene.

  In the said base material layer, the said thermoplastic resin may be used independently and may use 2 or more types together. Combination forms include blending and copolymerization.

  A commercially available product may be used as the thermoplastic resin. Specific examples of commercially available thermoplastic resins include trade name “PF380A” (block polypropylene) manufactured by Sun Allomer.

  The base material layer may contain any appropriate additive as required. Examples of the additive that can be contained in the base material layer include an ultraviolet absorber, a heat stabilizer, a filler, and a lubricant. The kind, number, and amount of additives contained in the base material layer can be appropriately set according to the purpose.

  Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, benzoate compounds, and the like. Any appropriate content can be adopted as the content of the ultraviolet absorber as long as it does not bleed out during the formation of the laminated film. Typically, it is 0.01 part by weight to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin in the base material layer.

  Examples of the heat resistance stabilizer include hindered amine compounds, phosphorus compounds, and cyanoacrylate compounds. Any appropriate content can be adopted as the content of the heat-resistant stabilizer as long as it does not bleed out when the laminated film is formed. Typically, it is 0.01 part by weight to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin in the base material layer.

  Examples of the filler include inorganic fillers such as talc, titanium oxide, calcium carbonate, clay, mica, barium sulfate, whisker, and magnesium hydroxide. The average particle diameter of the filler is preferably 0.1 μm to 10 μm. The content of the filler is preferably 1 part by weight to 200 parts by weight with respect to 100 parts by weight of the thermoplastic resin in the base material layer.

A-1-2. Roughness layer The thickness of the roughness layer is preferably 2 μm to 10 μm, more preferably 2 μm to 8 μm, and particularly preferably 2 μm to 5 μm. When the thickness of the roughness developing layer is less than 2 μm, it may be difficult to obtain a desired surface roughness. When the thickness of the roughness developing layer is thicker than 10 μm, the mechanical properties of the roughness developing layer affect the overall physical properties of the laminate (I) and thus the entire adhesive tape, and the laminate (I) and the handling of the adhesive tape are May be worse.

  Any appropriate value can be adopted as the haze value of the roughness expressing layer as long as the haze value of the laminate (I) in the present invention is 30% or less.

  The roughness expressing layer contains at least one resin component (A) selected from polyethylene, ethylene-vinyl acetate copolymer, propylene-based polymer, and olefin-based thermoplastic elastomer. Preferably, at least one resin component (A) selected from a propylene-based polymer and an olefin-based thermoplastic elastomer is included.

  Specific examples of the propylene-based polymer include homopolypropylene, block polypropylene, and random polypropylene.

  Moreover, you may use the polypropylene obtained using a metallocene catalyst as a propylene-type polymer.

  Any appropriate olefinic thermoplastic elastomer can be adopted as the olefinic thermoplastic elastomer as long as it is an olefinic thermoplastic elastomer called TPO. The olefin-based thermoplastic elastomer is typically a hard segment portion made of polyethylene or polypropylene and a soft segment portion which is a rubber component (hydrogenated (styrene) butadiene rubber or ethylene-propylene rubber (EPDM, EPM, EBM, etc.)). And have.

  It is one of the preferable forms that the said roughness expression layer contains 2 or more types of resin which shows a different melt flow rate. By including two or more kinds of resins exhibiting different melt flow rates, a resin having a high melt flow rate (low-viscosity resin) is stretched when the material that forms the roughness developing layer is stretched in a hot melt state to be molded. Resin that has a low melt flow rate (high viscosity resin) is easy to stretch, so that a high melt flow rate resin forms a sea part, and a low melt flow rate resin forms an island part. An expression layer can be obtained. As a result, the surface roughness can be expressed in the roughness expressing layer due to the unevenness caused by the sea-island structure. The melt flow rate can be measured by a method according to JISK7210.

  The melt flow rate of the resin having a high melt flow rate (low viscosity resin) is preferably 5 g / 10 min to 100 g / 10 min, more preferably 5 g / 10 min to 80 g / 10 min, and particularly preferably 5 g / 10 min to 50 g / 10 min. When the melt flow rate of the high melt flow rate resin is less than 5 g / 10 min, the difference in melt flow rate between the low melt flow rate resin and the high melt flow rate resin is small, The surface roughness may be too small. When it is larger than 100 g / 10 min, the surface roughness of the roughness developing layer may be too large.

  The melt flow rate of the low melt flow rate resin (high viscosity resin) is preferably 0.1 g / 10 min to 4.9 g / 10 min, more preferably 0.2 g / 10 min to 4.5 g / 10 min. Particularly preferably, it is 0.2 g / 10 min to 3 g / 10 min. When the melt flow rate of the resin having a low melt flow rate is smaller than 0.1 g / 10 min, the surface roughness of the roughness developing layer may be too large. When it is larger than 7 g / 10 min, the difference in melt flow rate between the resin having a high melt flow rate and the resin having a low melt flow rate is small, and the surface roughness of the roughness developing layer may be too small.

  If the melt flow rate of the resin having a high melt flow rate (low viscosity resin) and the resin having a low melt flow rate (high viscosity resin) is in the above range, the resin having a high melt flow rate has a sea portion. A roughness developing layer having a sea-island structure in which a resin having a low melt flow rate is formed to form an island portion can be obtained.

  By adjusting the difference between the melt flow rate of the resin having a high melt flow rate (low viscosity resin) and the melt flow rate of the resin having a low melt flow rate (high viscosity resin), the surface roughness of the roughness developing layer Can be controlled. That is, when the difference in melt flow rate is large, the difference in ease of elongation of the material that forms the roughness developing layer is large, and a roughness developing layer having a clear sea-island structure can be obtained, so the surface roughness is large. A roughness expressing layer can be obtained. On the other hand, when the difference in melt flow rate is small, the difference in easiness of elongation of the roughness developing layer forming material is small, and it is difficult to obtain a roughness developing layer having a clear sea-island structure. The expression layer will be obtained.

  The roughness developing layer preferably has two or more melting temperatures Tm in differential scanning calorimetry (DSC). Such a roughness expressing layer can be obtained by using two or more kinds of resins having different melting points. By using two or more kinds of resins having different melting points in the roughness developing layer, the surface roughness of the roughness developing layer can be adjusted by the difference in melting point. More specifically, when the film is formed by cooling and solidifying after heat melting, the high melting point resin is solidified first, and then the low melting point resin is solidified. A clear sea-island structure can be obtained in the thickness developing layer, and as a result, a roughness developing layer having a large surface roughness can be obtained. On the other hand, when the difference in melting point is small, it is difficult to obtain a roughness-expressing layer having a clear sea-island structure, so that a roughness-expressing layer having a small surface roughness is obtained. In addition, the said melting temperature Tm can be measured by the method according to JISK7121. In this specification, “having two or more melting temperatures Tm” means that two or more melting endothermic peaks occur in the DSC curve.

  When the roughness expressing layer is formed using two kinds of resins having different melting points, the difference in melting point is preferably 5 ° C to 65 ° C, more preferably 10 ° C to 60 ° C, particularly preferably. Is 15 ° C to 50 ° C. If the melting point difference is within such a range, a clear sea-island structure can be obtained in the roughness developing layer, and as a result, a roughness developing layer having a large surface roughness can be obtained.

  The surface roughness of the roughness developing layer can be adjusted by the compatibility of two or more kinds of resins contained in the roughness developing layer. When the compatibility is low, a clear sea-island structure can be obtained in the above-described roughness developing layer, so that a roughness developing layer having a large surface roughness can be obtained. On the other hand, when the compatibility is high, it is difficult to obtain a clear sea-island structure, so that a roughness expressing layer having a small surface roughness is obtained.

  In forming the roughness developing layer, there is a method using not only a method using two or more kinds of resins as described above but also a method using a single resin. Examples of such a single resin include a block polymer having a low viscosity portion (soft segment) and a high viscosity portion (hard segment). Specific examples include olefinic thermoplastic elastomers made of block copolymers.

From the above, as the resin component (A) (resin component (A) contained in the roughness expression layer) used for forming the roughness expression layer, preferably, for example,
(1) A combination of a low viscosity resin and a high viscosity resin,
(2) A combination of a high melting point resin and a low melting point resin,
(3) a combination of resins having low compatibility with each other;
(4) a block polymer having a low viscosity portion (soft segment) and a high viscosity portion (hard segment);
Is mentioned. Specifically, for example, a combination of a propylene-based polymer and an olefin-based thermoplastic elastomer, an olefin-based thermoplastic elastomer having a low viscosity portion (soft segment) and a high viscosity portion (hard segment), and the like can be mentioned.

  Commercially available products may be used for the propylene-based polymer and the olefin-based thermoplastic elastomer.

  Specific examples of commercially available propylene-based polymers include trade names “Wintech WFX4” and “Wintech WFX6” manufactured by Nippon Polypro. Specific examples of commercially available olefin-based thermoplastic elastomers include trade name “Cataloy Q300F” manufactured by Sun Allomer Co., Ltd.

  The said roughness expression layer can contain arbitrary appropriate additives as needed. As the additive that can be contained in the roughness developing layer, for example, the additive described in the section A-1-1 can be used.

A-1-3. Fine concavo-convex erasing layer The thickness of the fine concavo-convex erasing layer is preferably 1 μm to 10 μm, more preferably 1 μm to 7 μm, still more preferably 1 μm to 5 μm, and particularly preferably 2 μm to 5 μm. When the thickness of the fine concavo-convex erasure layer is thinner than 1 μm, the fine concavo-convex cannot be sufficiently erased, and the haze of the entire laminate (I) in the present invention may be increased. When the thickness of the fine concavo-convex erasure layer is larger than 10 μm, there is a possibility that even large concavo-convex portions may be buried, and the surface roughness of the laminate (I) in the present invention may become smooth.

  Any appropriate value can be adopted as the haze value of the fine unevenness erasing layer as long as the haze value of the laminate (I) in the present invention is 30% or less.

  The fine unevenness erasing layer includes a thermoplastic resin (B).

  Any appropriate thermoplastic resin can be adopted as the thermoplastic resin (B). For example, the thermoplastic resin described in the section A-1-1 can be used. The thermoplastic resin (B) is preferably polyethylene.

  In the laminate (I) in the present invention, the roughness formed by the roughness-expressing layer is composed of fine unevenness and large unevenness, but the fine unevenness is not filled by the fine unevenness erasing layer. It is necessary to do so. For this reason, it is preferable that the melt flow rate of the thermoplastic resin (B) contained in the said fine unevenness | corrugation elimination layer is larger than any melt flow rate of the resin component (A) contained in the roughness expression layer mentioned above.

  The melt flow rate of the fine unevenness erasing layer is preferably 6 g / 10 min to 100 g / 10 min, more preferably 7 g / 10 min to 80 g / 10 min, and particularly preferably 8 g / 10 min to 50 g / 10 min.

  The fine unevenness erasing layer may further contain a release agent such as a silicone release agent, a fluorine release agent, a long-chain alkyl release agent, an aliphatic amide release agent, if necessary. If the fine concavo-convex erasing layer includes a release agent, it is possible to prevent sticking between the fine concavo-convex erasure layer and the second pressure-sensitive adhesive layer in a state where the adhesive tapes overlap each other, for example, in a roll form. . Moreover, since it is not necessary to cover a fine unevenness | corrugation elimination layer with a separator layer, the adhesive tape which has a desired haze value and surface roughness can be obtained easily. Among the release agents, long chain alkyl release agents are particularly preferable. In addition, the method for performing the release treatment on the fine unevenness erasing layer is not limited to the method of adding various release materials such as the above-described release agent, and any appropriate within a range not impairing the effects of the present invention, You may use the method of rubbing a fine uneven | corrugated erase layer, and the method of irradiating an electron beam to a fine uneven | corrugated erase layer and expressing mold release property.

  The long-chain alkyl release agent includes a long-chain alkyl polymer. The long-chain alkyl polymer can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group in any appropriate heating solvent. During the reaction, a catalyst may be used as necessary. Examples of the catalyst include tin compounds and tertiary amines.

  Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and a maleic anhydride group. Examples of the polymer having a reactive group include an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyethyleneimine, polyethyleneamine, and a styrene-maleic anhydride copolymer. Of these, an ethylene-vinyl alcohol copolymer is preferred. The ethylene-vinyl alcohol copolymer is a concept including a partially saponified product of an ethylene-vinyl acetate copolymer. Polyvinyl alcohol is a concept including a partially saponified product of polyvinyl acetate.

  The number of carbon atoms of the alkyl group is preferably 8-30, and more preferably 12-22. When the number of carbon atoms of the alkyl group is in such a range, a roughness developing layer having excellent peelability can be obtained. Specific examples of such an alkyl group include a lauryl group, a stearyl group, and a behenyl group. Examples of the compound having an alkyl group (that is, a compound having an alkyl group capable of reacting with the reactive group) include isocyanates such as octyl isocyanate, decyl isocyanate, lauryl isocyanate, stearyl isocyanate; acid chlorides; amines; alcohols; Etc. Of these, isocyanate is preferable.

  The weight average molecular weight of the long-chain alkyl polymer is preferably 10,000 to 1,000,000, and more preferably 20,000 to 1,000,000. When the weight average molecular weight of the long-chain alkyl polymer is in such a range, a roughness expressing layer having excellent peelability can be obtained.

  The long-chain alkyl release agent is kneaded into the fine unevenness erasing layer when the laminated film or the adhesive tape is coextruded. The content of the long-chain alkyl release agent in the fine unevenness erasing layer is preferably 1% by weight to 50% by weight, more preferably 2% by weight to 30% by weight, and particularly preferably 5% by weight. -20% by weight. When the content is less than 1% by weight, the effect of adding the long-chain alkyl release agent may not be obtained. When the content ratio is more than 50% by weight, a bleed product may be generated.

A-2. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer The thicknesses of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are each preferably 1 μm to 300 μm, more preferably 1 μm to 100 μm, particularly preferably. 1 μm to 50 μm.

  Any appropriate value can be adopted as the haze value of each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer.

  Arbitrary appropriate adhesives can each be employ | adopted for the adhesive which comprises the said 1st adhesive layer and the said 2nd adhesive layer. Examples of the pressure sensitive adhesive include rubber pressure sensitive adhesive, acrylic pressure sensitive adhesive, and silicone pressure sensitive adhesive.

  A thermoplastic adhesive can also be used as the adhesive. Examples of the material constituting the thermoplastic pressure-sensitive adhesive include any appropriate styrene block copolymer and acrylic thermoplastic resin as the pressure-sensitive adhesive material.

  Specific examples of the styrenic block copolymer include styrenic AB-type diblock copolymers such as styrene-ethylene-butylene copolymer (SEB); styrene-butadiene-styrene copolymer (SBS), and SBS. Hydrogenated product (styrene-ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), hydrogenated product of SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)) ), Styrene-ABA type triblock copolymer such as styrene-isobutylene-styrene copolymer (SIBS); styrene type ABAB type tetrablock copolymer such as styrene-butadiene-styrene-butadiene (SBSB); styrene-butadiene -Styrene-butadiene-styrene (SBSBS), etc. Styrene-based ABABA-type pentablock copolymer; Styrene-based multiblock copolymer having AB repeating units higher than these; Hydrogenation of ethylenic double bonds of styrene-based random copolymers such as styrene-butadiene rubber (SBR) And the like. Examples of commercially available products include “Tuftec H1062” and “Tuftec H1041” and “Tuftec H1221” (styrene elastomer) manufactured by Asahi Kasei Chemicals, “Dynalon 1320P” (styrene elastomer) manufactured by JSR, and manufactured by Kraton Polymer. “G1657” (styrene-based elastomer). The said copolymer may be used independently and may use 2 or more types together.

  The content of the styrene block structure in the styrenic block copolymer is preferably 5 to 40% by weight, more preferably 7 to 30% by weight, and particularly preferably 9 to 20% by weight. % By weight. When the content of the styrene block structure is less than 5% by weight, adhesive residue due to insufficient cohesive force of the pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer) is likely to occur. When the content ratio of the styrene block structure is more than 40% by weight, the pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer) becomes hard, and good adhesion to a rough surface cannot be obtained. There is a fear.

  When the styrenic block copolymer has an ethylene-butylene block structure, the content of the structural unit derived from butylene in the ethylene-butylene block structure is preferably 50% by weight or more, more preferably 60% by weight or more, particularly Preferably it is 70 weight% or more, Most preferably, it is 70 weight%-90 weight%. If the content ratio of the structural unit derived from butylene is within such a range, the pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer is excellent in wettability and adhesiveness, and can adhere well to a rough surface. Pressure-sensitive adhesive layer) can be obtained.

  Examples of the acrylic thermoplastic resin include polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate copolymer (PMMA-PBA-PMMA copolymer); polybutyl acrylate having a carboxylic acid as a functional group. And the type of PMMA-functional group-containing PBA-PMMA copolymer. A commercially available product may be used as the acrylic thermoplastic resin. Specific examples of commercially available acrylic thermoplastic resins include trade name “NABSTAR” manufactured by Kaneka Corporation and trade name “LA polymer” manufactured by Kuraray Co., Ltd.

  Each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may contain other components as necessary. Examples of other components include olefin resins; silicone resins; liquid acrylic copolymers; polyethyleneimines; fatty acid amides; phosphate esters; The type, number and amount of the other components can be appropriately set according to the purpose. Examples of the additives include tackifiers; softeners; anti-aging agents; hindered amine light stabilizers; ultraviolet absorbers; heat stabilizers; filling with calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, and the like. Agent or pigment; and the like.

  The formulation of the tackifier is effective for improving the adhesive strength. The amount of the tackifier is appropriately determined to be any appropriate amount depending on the adherend in order to avoid the occurrence of the adhesive residue problem due to the decrease in cohesive force. Usually, with respect to 100 parts by weight of the pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer, preferably 0 to 40 parts by weight, more preferably 0 to 30 parts by weight, and even more preferably 0 to 10 parts by weight. Part.

  Examples of the tackifier include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, and coumarone-indene resins. Terpene resin, terpene phenol resin, rosin resin such as polymerized rosin, (alkyl) phenol resin, xylene resin or hydrogenated products thereof. A tackifier may be used independently and may use 2 or more types together.

  As the tackifier, hydrogenated tackifiers such as “Arcon P-125” manufactured by Arakawa Chemical Industries, Ltd. are preferable from the viewpoint of peelability and weather resistance. In addition, what is marketed as a blend with an olefin resin and a thermoplastic elastomer can also be used for a tackifier.

  The blending of the softener is effective for improving the adhesive strength. Examples of the softening agent include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, and derivatives thereof. Examples of the derivative include those having an OH group or a COOH group at one or both ends. Specific examples include hydrogenated polybutadiene diol, hydrogenated polybutadiene monool, hydrogenated polyisoprene diol, and hydrogenated polyisoprene monool. In order to further suppress the improvement in adhesiveness to the adherend, hydrogenated products of diene polymers such as hydrogenated polybutadiene and hydrogenated polyisoprene, olefinic softeners, and the like are preferable. Specific examples include “Kuraprene LIR-200” manufactured by Kuraray. These softeners may be used alone or in combination of two or more.

  The molecular weight of the softening agent can be appropriately set to any appropriate amount. If the molecular weight of the softening agent becomes too small, there is a risk of causing material transfer or heavy release from the pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer) to the adherend, The number average molecular weight of the softener is preferably 5,000 to 100,000, more preferably 10,000 to 50,000 because the molecular weight of the softener tends to be poor in improving the adhesive force.

  When using a softening agent, the addition amount can employ | adopt arbitrary appropriate amounts. If the amount of the softener added is too large, the adhesive residue tends to increase when exposed to high temperatures or outdoors. Therefore, it is preferably 40 parts by weight or less, more preferably 20 parts by weight with respect to 100 parts by weight of the adhesive. Part or less, more preferably 10 parts by weight or less. When the addition amount of the softening agent exceeds 40 parts by weight with respect to 100 parts by weight of the pressure-sensitive adhesive, the adhesive residue becomes remarkable under high temperature environment and outdoor exposure.

  Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, benzoate compounds, and the like. Any appropriate content can be adopted as the content of the ultraviolet absorber as long as it does not bleed out during molding. Typically, it is 0.01 to 5 parts by weight with respect to 100 parts by weight of the adhesive.

  Examples of the heat resistance stabilizer include hindered amine compounds, phosphorus compounds, and cyanoacrylate compounds. Any appropriate content can be adopted as the content of the heat-resistant stabilizer as long as it does not bleed out during molding. Typically, it is 0.01 to 5 parts by weight with respect to 100 parts by weight of the adhesive.

  Each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be surface-treated on one side or both sides as necessary. Examples of the surface treatment include corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment, and sputter etching treatment.

The storage elastic modulus (G ′) of the first pressure-sensitive adhesive layer is a frequency of 10 Hz and 23 ° C., preferably 1.0 × 10 ⁶ Pa or more and less than 1.0 × 10 ⁹ Pa, more preferably 1.0. × 10 ⁶ Pa or more and less than 1.0 × 10 ⁸ Pa, more preferably 1.0 × 10 ⁶ Pa or more and less than 1.0 × 10 ⁷ Pa. If the storage elastic modulus of the first pressure-sensitive adhesive layer falls within the above range, a member having irregularities on the surface is protected with the pressure-sensitive adhesive tape of the present invention having the first pressure-sensitive adhesive layer to form a laminate or a long roll. When deformed, it is possible to effectively prevent the uneven shape from being deformed and the base material layer in the adhesive tape from being damaged. Further, if the storage elastic modulus of the first pressure-sensitive adhesive layer is within the above range, the pressure-sensitive adhesive tape is affixed when the prism sheet is protected with the pressure-sensitive adhesive tape of the present invention and laminated or elongated. It is possible to effectively suppress unevenness (push marks) in the appearance of the prism sheet.

The storage elastic modulus (G ′) of the second pressure-sensitive adhesive layer is a frequency of 10 Hz and 23 ° C., preferably 1.0 × 10 ³ Pa or more and less than 1.0 × 10 ⁶ Pa, more preferably 5.0. × 10 ³ Pa or more and less than 1.0 × 10 ⁶ Pa, more preferably 1.0 × 10 ⁴ Pa or more and less than 1.0 × 10 ⁶ Pa. If the storage elastic modulus of the second pressure-sensitive adhesive layer falls within the above range, the pressure-sensitive adhesive tape of the present invention having the second pressure-sensitive adhesive layer has sufficient adhesion to a member having irregularities on the surface and sufficient peelability. Can be provided at the same time. Moreover, if the storage elastic modulus of the said 2nd adhesive layer is settled in the said range, the adhesive of this invention can be equipped with both sufficient adhesiveness to a prism sheet, and sufficient peelability.

  In addition, the storage elastic modulus (G ′) in the present invention is −50 ° C. to 100 ° C. at a frequency of 10 Hz and a heating rate of 5 ° C./min by a dynamic viscoelastic spectrum measuring instrument (ARES manufactured by Rheometric Scientific). The value measured in the range of ° C. In the case of a laminate in which two or more adhesive layers are laminated as in the adhesive tape of the present invention, the laminate is obliquely cut using, for example, SAICAS (Surface And Interfacial Cutting Analysis System). The cut surface may be measured at a plurality of locations using a micro-part hardness measuring device such as a nanoindenter.

In the adhesive tape of this invention, it is preferable that the storage elastic modulus of the said 1st adhesive layer is higher than the storage elastic modulus of the said 2nd adhesive layer. If the storage elastic modulus of the first pressure-sensitive adhesive layer is higher than the storage elastic modulus of the second pressure-sensitive adhesive layer, the pressure-sensitive adhesive tape of the present invention has sufficient adhesion to a member having irregularities on the surface and sufficient peelability. It is possible to provide both of the above and the uneven shape becomes difficult to be deformed even when the member protected by the adhesive tape is deformed by laminating or wrapping, etc., and in the adhesive tape The base material layer is hardly damaged. Further, if the storage elastic modulus of the first pressure-sensitive adhesive layer is larger than the storage elastic modulus of the second pressure-sensitive adhesive layer, the pressure-sensitive adhesive tape of the present invention achieves both sufficient adhesion to the prism sheet and sufficient peelability. In addition, when the prism sheet protected with the adhesive tape is put into a laminated or long-winded state, the appearance of the prism sheet to which the adhesive tape is affixed is uneven. This can be effectively suppressed. In the pressure-sensitive adhesive tape of the present invention, the difference between the storage elastic modulus of the first pressure-sensitive adhesive layer at a frequency of 10 Hz and 23 ° C. and the storage elastic modulus of the second pressure-sensitive adhesive layer at a frequency of 10 Hz and 23 ° C. is 3 × 10 ⁵ Pa. The above is preferable. The difference in the storage elastic modulus is more preferably 4 × 10 ⁵ Pa to 1 × 10 ⁷ Pa, and further preferably 5 × 10 ⁵ Pa to ⁵ × 10 ⁶ Pa. If the difference between the storage elastic modulus at a frequency of 10 Hz and 23 ° C. of the first pressure-sensitive adhesive layer and the storage elastic modulus at a frequency of 10 Hz and 23 ° C. of the second pressure-sensitive adhesive layer is 3 × 10 ⁵ Pa or more, The pressure-sensitive adhesive tape can be provided with both sufficient adhesion to a member having irregularities on the surface and sufficient releasability, and the member protected with the pressure-sensitive adhesive tape can be laminated or wound long Even when deformed, the uneven shape is not easily deformed, and the base material layer in the adhesive tape is hardly damaged.

B. Manufacturing method of an adhesive tape The adhesive tape of this invention can be obtained by arbitrary appropriate manufacturing methods. The pressure-sensitive adhesive tape of the present invention includes, for example, the fine unevenness erasing layer, the roughness developing layer, the base material layer, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive layer that constitute the pressure-sensitive adhesive tape of the present invention. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are formed on the base material layer of the laminate comprising the extrusion method (production method 1), the fine unevenness erasing layer, the roughness developing layer, and the base material layer. The first pressure-sensitive adhesive layer is dissolved on the base material layer of the laminate comprising the method (manufacturing method 2) of hot melt coating in order, the fine unevenness erasing layer, the roughness developing layer, and the base material layer. The organic solvent coating liquid or the emulsion liquid in which the first pressure-sensitive adhesive layer is dispersed in water is applied, and then the organic solvent coating liquid in which the second pressure-sensitive adhesive layer is dissolved or the second pressure-sensitive adhesive layer is dispersed in water. The method (manufacturing method 3) etc. which apply | coat an emulsion liquid are mentioned.

  When manufacturing an adhesive tape by the said manufacturing method 1 or 2, the said thermoplastic adhesive is preferably used as an adhesive which comprises an adhesive layer (a 1st adhesive layer or a 2nd adhesive layer).

  In the production method 1, the coextrusion method includes fine unevenness erasing layer forming material, roughness developing layer forming material, base material layer forming material, first pressure-sensitive adhesive layer forming material, and second pressure-sensitive adhesive layer forming material. Can be carried out using an extruder and a co-extrusion die according to the inflation method, the T-die method, or the like.

  When manufacturing an adhesive tape by the said manufacturing method 2 or 3, Preferably, on the surface in which an adhesive layer (a 1st adhesive layer or a 2nd adhesive layer) is formed, ie, the said base material layer of the said laminated body. Easy adhesion treatment is applied. Examples of the easy adhesion treatment include corona discharge treatment, itro treatment (silicic acid flame treatment), and anchor coat treatment.

  When manufacturing an adhesive tape by the said manufacturing method 3, as an adhesive which comprises the said adhesive layer (a 1st adhesive layer or a 2nd adhesive layer), the said rubber adhesive, an acrylic adhesive, or a silicone type An adhesive is preferably used.

  When manufacturing an adhesive tape with the said manufacturing method 3, the said organic solvent can employ | adopt arbitrary appropriate things. Examples of the organic solvent include aromatic hydrocarbon solvents such as toluene and xylene; aliphatic carboxylic acid ester solvents such as ethyl acetate; aliphatic hydrocarbon solvents such as hexane, heptane and octane. The said organic solvent may be used independently and may use 2 or more types together.

  When manufacturing an adhesive tape by the said manufacturing method 3, the crosslinking agent may be included in the organic-solvent coating liquid. Examples of the crosslinking agent include an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, and an aziridine crosslinking agent.

  Arbitrary appropriate coating methods can be employ | adopted for the coating method in the case of manufacturing an adhesive tape by the said manufacturing method 3. FIG. Examples of the coating method include a method using a bar coater, a gravure coater, a spin coater, a roll coater, a knife coater, an applicator and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. In addition, the test and evaluation method in an Example etc. are as follows. Moreover, a part means a weight part.

(1) Arithmetic average surface roughness Ra
After laminating the laminated film or the adhesive tape to the slide glass, the surface roughness of the surface layer is measured using an optical profiler NT9100 (manufactured by Veeco), Measurement Type: VSI (Infinite Scan), Objective: 2.5X. , FOV: 1.0X, Modulation Threshold: 0.1%, and measured at n = 3. After the measurement, data analysis was performed using Terms Remov: Tilt Only (Plane Fit) and Window Filtering: None to obtain the arithmetic average surface roughness Ra.
(2) Haze value The haze value was measured using a haze meter HM-150 (Murakami Color Research Laboratory Co., Ltd.). The haze was calculated by haze (%) = Td / Tt X 100 (Td: diffuse transmittance, Tt: total light transmittance) in accordance with JISK7136.
(3) Storage elastic modulus (G ')
The material for forming each pressure-sensitive adhesive layer was kneaded with a biaxial kneader, and then formed into a film (200 μm). The storage elastic modulus of this molded sample was measured in a range of −50 ° C. to 100 ° C. at a frequency of 10 Hz and a temperature increase rate of 5 ° C./min using a dynamic viscoelastic spectrum measuring instrument (ARES manufactured by Rheometric Scientific). It was measured.
(4) Adhesive strength evaluation The adhesive strength of the adhesive tape was measured based on JISZ0237 (2000). A test sample obtained by cutting the adhesive tape into a predetermined width (20 mm) was attached to the prism sheet, and this was pressure-bonded once with a rubber roller under a load of 2 kg. Then, the load of 11 g / cm < ² > was applied and it was left to stand in 50 degreeC atmosphere for 24 hours. This sample was peeled off in the 180 ° direction at a tensile speed of 300 mm / min, and the resistance value at that time was taken as the adhesive strength of the test sample. All peeling operations were performed in an atmosphere of a temperature of 23 ° C. and a humidity of 65% RH (relative humidity).
(5) Evaluation of prism sheet lens top angle partial filling depth A test sample obtained by cutting an adhesive tape into 20 cm x 5 cm is attached to a prism sheet cut into a size of 20 cm x 5 cm, and this is loaded with a load of 2 kg. Press-bonded once with a rubber roller. Then, the load of 11 g / cm < ² > was applied and it was left to stand in 50 degreeC atmosphere for 24 hours. Thereafter, the test sample was peeled off from the prism sheet, and the prism sheet lens apex angle partial biting depth was evaluated by an optical profiler NT9100 (manufactured by Veeco) for the surface attached to the prism sheet of the test sample. Measurement conditions are VSI, objective lens: 2.5 times, internal lens: 0.5 times, Backscan: 10 μm, Length: 15 μm, threshold: 1%, Window Filtering: None, 5 mm × 5 mm, n = The measurement was carried out at 10. The average of this data was calculated.
(6) Evaluation of deformation of prism sheet apex angle The uneven surface of the prism sheet from which the test sample was peeled in (5) was visually observed to evaluate whether the apex angle was not deformed. If the apex angle is deformed, the color can be evaluated differently only at the deformed portion of the light and can be evaluated.
○: Deformation was not observed ×: Deformation was observed (7) Press mark observation The lens surface of the prism sheet from which the test sample was peeled in (5) above was visually observed, and no mark was generated. Observations were made.
○: No imprint was observed ×: Imprint was observed

[Example 1]
The following compounds were prepared as a roughness developing layer forming material, a fine unevenness erasing layer forming material, a base material layer forming material, a first pressure-sensitive adhesive layer forming material, and a second pressure-sensitive adhesive layer.
Roughness layer forming material: Reactor TPO (manufactured by Sun Allomer Co., Ltd .: Catalloy Q300F; Melt Flow Rate (MFR) = 0.8 (230 ° C., 2.16 kgf)) 75 parts, obtained using a metallocene catalyst Polypropylene (Nippon Polypro Co., Ltd .: Wintech WFX4; Melt flow rate (MFR) = 7.0 (230 ° C., 2.16 kgf)) 25 parts mixture Fine unevenness erasing layer forming material: Low density polyethylene ( Manufactured by Nippon Polyethylene Co., Ltd .: Novatec LD LC720; Melt flow rate (MFR) = 9.4 (190 ° C., 2.16 kgf))
Base material layer forming material: Block polypropylene (manufactured by Sun Aroma: PF380A)
First pressure-sensitive adhesive layer forming material: 75 parts of a styrene-based elastomer (made by Asahi Kasei Chemicals: Tuftec H1041) made of a hydrogenated styrene-butadiene copolymer, and a tackifier (made by Arakawa Chemical Industries: Alcon P-) 125) Mixture with 25 parts Second pressure-sensitive adhesive layer forming material: 75 parts of a styrene elastomer (made by Kraton: G1657) made of a hydrogenated styrene-butadiene copolymer, and a tackifier (Arakawa Chemical Industries, Ltd.) Manufactured: Alcon P-125) Mixture with 25 parts The above material is molded by T-die melt coextrusion to form a fine relief layer, roughness developing layer, substrate layer, first pressure-sensitive adhesive layer, and second pressure-sensitive adhesive An adhesive tape (1) provided with the agent layers in this order was obtained. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (1).

[Example 2]
An adhesive tape (2) was obtained in the same manner as in Example 1 except that the thickness of the roughness developing layer was 5 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (2).

[Example 3]
An adhesive tape (3) was obtained in the same manner as in Example 1 except that the thickness of the roughness developing layer was 10 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 10 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (3).

[Example 4]
As the first pressure-sensitive adhesive layer forming material, 95 parts of a styrene-based elastomer (made by Asahi Kasei Chemicals: Tuftec H1062) made of a hydrogenated styrene-butadiene copolymer, and a tackifier (made by Arakawa Chemical Industries: Alcon P) -125) 95 parts of a styrene elastomer (manufactured by JSR: Dynalon 1320P) made of a hydrogenated styrene-butadiene copolymer as a second pressure-sensitive adhesive layer forming material using a mixture with 5 parts, and tackifying A pressure-sensitive adhesive tape (4) was obtained in the same manner as in Example 1 except that a mixture with 5 parts of an agent (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (4).

[Example 5]
An adhesive tape (5) was obtained in the same manner as in Example 4 except that the thickness of the roughness expressing layer was 5 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (5).

[Example 6]
An adhesive tape (6) was obtained in the same manner as in Example 4 except that the thickness of the roughness developing layer was 10 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 10 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results of the obtained adhesive tape (6).

[Example 7]
The first pressure-sensitive adhesive was only 100 parts of reactor TPO (manufactured by Sun Allomer Co., Ltd .: Catalloy Q300F; Melt Flow Rate (MFR) = 0.8 (230 ° C., 2.16 kgf)) as the roughness developing layer forming material. As layer-forming materials, 70 parts of a styrene elastomer (made by Asahi Kasei Chemicals: Tuftec H1041) made of a hydrogenated product of a styrene-butadiene copolymer, and a tackifier (Arakawa Chemical Industries, Ltd .: Alcon P-125) 30 And 70 parts of a styrene elastomer (made by JSR: Dynalon 1320P) made of a hydrogenated styrene-butadiene copolymer, and a tackifier (Arakawa Chemical). Kogyo Co., Ltd .: Alcon P-125) Adhesive tape in the same manner as in Example 1 except that a mixture with 30 parts was used. 7) was obtained. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results of the obtained adhesive tape (7).

[Example 8]
An adhesive tape (8) was obtained in the same manner as in Example 7 except that the thickness of the roughness developing layer was 5 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results of the obtained adhesive tape (8).

[Example 9]
An adhesive tape (9) was obtained in the same manner as in Example 7 except that the thickness of the roughness developing layer was 10 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 10 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (9).

[Example 10]
As a second pressure-sensitive adhesive layer forming material, 70 parts of a styrene elastomer (made by Asahi Kasei Chemicals: Tuftec H1221) made of a hydrogenated styrene-butadiene copolymer, and a tackifier (made by Arakawa Chemical Industries: Alcon P) -125) An adhesive tape (10) was obtained in the same manner as in Example 7 except that a mixture with 30 parts was used. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results of the obtained adhesive tape (10).

[Example 11]
An adhesive tape (11) was obtained in the same manner as in Example 10 except that the thickness of the roughness developing layer was 5 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results for the obtained adhesive tape (11).

[Example 12]
An adhesive tape (12) was obtained in the same manner as in Example 10 except that the thickness of the roughness developing layer was 10 μm. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 10 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 1 shows the evaluation results of the obtained adhesive tape (12).

[Comparative Example 1]
As a material for forming a roughness developing layer, an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Evaflex EV270; Melt Flow Rate (MFR) = 1.0 (190 ° C., 2.16 kgf)) 30 Part and low density polyethylene (Tosoh Corp .: Petrocene 209; Melt flow rate (MFR) = 45 (190 ° C., 2.16 kgf)) 70 parts, Hydrogenation of a styrene-butadiene copolymer as a second pressure-sensitive adhesive layer forming material using only 100 parts of a styrene elastomer (made by Asahi Kasei Chemicals Co., Ltd .: Tuftec H1041) comprising a hydrogenated product of a styrene-butadiene copolymer. Only 100 parts of styrene elastomer (made by Asahi Kasei Chemicals: Tuftec H1062) Otherwise, in the same manner as in Example 1 to obtain an adhesive tape (C1). The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C1).

[Comparative Example 2]
The thickness of the roughness developing layer is 5 μm, and 70 parts of a styrene elastomer (made by Kraton: G1657) made of a hydrogenated styrene-butadiene copolymer as a first pressure-sensitive adhesive layer forming material, and a tackifier ( Arakawa Chemical Industries, Ltd .: Alcon P-125) 30 parts mixture, and as the second pressure-sensitive adhesive layer forming material, a styrene elastomer (made by JSR: Dynalon) comprising a hydrogenated styrene-butadiene copolymer. 1320P) An adhesive tape (C2) was obtained in the same manner as in Comparative Example 1 except that a mixture of 70 parts and 30 parts of a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results for the obtained adhesive tape (C2).

[Comparative Example 3]
The thickness of the roughness developing layer is 10 μm, and 75 parts of a styrene elastomer (made by Kraton: G1657) made of a hydrogenated styrene-butadiene copolymer as a first pressure-sensitive adhesive layer forming material, and a tackifier ( Arakawa Chemical Industries, Ltd .: Alcon P-125) A mixture with 25 parts, and as a second pressure-sensitive adhesive layer forming material, a styrene elastomer (made by JSR: Dynalon) comprising a hydrogenated styrene-butadiene copolymer. 1320P) An adhesive tape (C3) was obtained in the same manner as in Comparative Example 1 except that a mixture of 75 parts and a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) 25 parts was used. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 10 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results for the obtained adhesive tape (C3).

[Comparative Example 4]
Without providing a fine unevenness erasing layer, as a first pressure-sensitive adhesive layer forming material, 95 parts of a styrene-based elastomer (made by Asahi Kasei Chemicals: Tuftec H1221) made of a hydrogenated styrene-butadiene copolymer, and a tackifier ( Arakawa Chemical Industries, Ltd .: Alcon P-125) and a mixture of 5 parts, a styrene elastomer (made by Asahi Kasei Chemicals Co., Ltd.) made of a hydrogenated styrene-butadiene copolymer as the second pressure-sensitive adhesive layer forming material. A pressure-sensitive adhesive tape (C4) was obtained in the same manner as in Example 1, except that a mixture of 95 parts of Tuftec H1062) and 5 parts of a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. The thickness of the fine unevenness erasing layer is 0 μm (not present), the thickness of the roughness developing layer is 2 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 4 μm, and the thickness of the second pressure-sensitive adhesive layer is 4 μm. Met. Table 2 shows the evaluation results of the obtained adhesive tape (C4).

[Comparative Example 5]
100 parts of reactor TPO (manufactured by Sun Allomer Co., Ltd .: Catalloy Q300F; Melt Flow Rate (MFR) = 0.8 (230 ° C., 2.16 kgf)) as a roughness developing layer forming material without providing a fine unevenness erasing layer As a first pressure-sensitive adhesive layer forming material, 70 parts of a styrene-based elastomer (manufactured by JSR: Dynalon 1320P) made of a hydrogenated styrene-butadiene copolymer and a tackifier (made by Arakawa Chemical Industries, Ltd.) : Alcon P-125) Adhesive tape (C5) in the same manner as in Example 1 except that a mixture with 30 parts was used, the thickness of the first adhesive layer was 8 μm, and the second adhesive layer was not provided. Got. The thickness of the fine unevenness erasing layer is 0 μm (not present), the thickness of the roughness developing layer is 2 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 8 μm, and the thickness of the second pressure-sensitive adhesive layer is 0 μm. (Not present). Table 2 shows the evaluation results of the obtained adhesive tape (C5).

[Comparative Example 6]
As a material for forming a roughness expression layer, only 100 parts of random polypropylene (manufactured by Nippon Polypro Co., Ltd .: Novatec PP EG8; melt flow rate (MFR) = 0.8 (230 ° C., 2.16 kgf)) was used, and the roughness was used. The thickness of the expression layer is 10 μm, and only 100 parts of a styrene elastomer (Asahi Kasei Chemicals: Tuftec H1041) made of a hydrogenated styrene-butadiene copolymer is used as the first pressure-sensitive adhesive layer forming material. A pressure-sensitive adhesive tape (C6) was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was 8 μm and the second pressure-sensitive adhesive layer was not provided. The thickness of the fine unevenness erasing layer is 2 μm, the thickness of the roughness developing layer is 10 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 8 μm, and the thickness of the second pressure-sensitive adhesive layer is 0 μm (not present). Met. Table 2 shows the evaluation results of the obtained adhesive tape (C6).

[Comparative Example 7]
An adhesive tape (C7) was obtained in the same manner as in Comparative Example 1 except that the fine unevenness erasing layer was not provided. The thickness of the fine unevenness erasing layer is 0 μm (not present), the thickness of the roughness developing layer is 2 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 4 μm, and the thickness of the second pressure-sensitive adhesive layer is 4 μm. Met. Table 2 shows the evaluation results of the obtained adhesive tape (C7).

[Comparative Example 8]
The fine unevenness erasing layer has a thickness of 1 μm, and as a first pressure-sensitive adhesive layer forming material, 70 parts of a styrene-based elastomer (made by Kraton: G1657) made of a hydrogenated styrene-butadiene copolymer, and a tackifier ( Arakawa Chemical Industries, Ltd .: Alcon P-125) 30 parts mixture, and as the second pressure-sensitive adhesive layer forming material, a styrene elastomer (made by JSR: Dynalon) comprising a hydrogenated styrene-butadiene copolymer. 1320P) An adhesive tape (C8) was obtained in the same manner as in Comparative Example 1 except that a mixture of 70 parts and a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. The thickness of the fine unevenness erasing layer was 1 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C8).

[Comparative Example 9]
As a material for forming a roughness developing layer, an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270; Melt Flow Rate (MFR) = 1.0 (190 ° C., 2.16 kgf)) 100 As a first pressure-sensitive adhesive layer forming material, 75 parts of a styrene elastomer (made by Kraton: G1657) made of a hydrogenated styrene-butadiene copolymer and a tackifier (made by Arakawa Chemical Industries) : Alcon P-125) 75 parts by weight as a second pressure-sensitive adhesive layer forming material with 75 parts of a styrene elastomer (made by JSR: Dynalon 1320P) made of hydrogenated styrene-butadiene copolymer, In the same manner as in Example 1 except that a mixture with 25 parts of a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. To obtain a pressure-sensitive adhesive tape (C9). The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 2 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C9).

[Comparative Example 10]
The thickness of the roughness expressing layer is 5 μm, and 95 parts of a styrene elastomer (made by Asahi Kasei Chemicals: Tuftec H1221) made of a hydrogenated styrene-butadiene copolymer is used as the first pressure-sensitive adhesive layer forming material. Styrene elastomer (Asahi Kasei Chemicals Co., Ltd.) comprising a hydrogenated product of a styrene-butadiene copolymer as a second pressure-sensitive adhesive layer forming material using a mixture with 5 parts of an agent (Arakawa Chemical Industries, Ltd .: Alcon P-125) Manufactured: Tuftec H1062) Adhesive tape (C10) was obtained in the same manner as Comparative Example 9 except that a mixture of 95 parts of tackifier and 5 parts of tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) was used. It was. The thickness of the fine unevenness erasing layer was 2 μm, the thickness of the roughness developing layer was 5 μm, the thickness of the base material layer was 38 μm, the thickness of the first pressure-sensitive adhesive layer was 4 μm, and the thickness of the second pressure-sensitive adhesive layer was 4 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C10).

[Comparative Example 11]
70 parts of a styrene elastomer (made by JSR: Dynalon 1320P) made of a hydrogenated styrene-butadiene copolymer as a first pressure-sensitive adhesive layer-forming material with a thickness of the roughness developing layer of 10 μm, and a tackifier (Arakawa Chemical Industries, Ltd .: Archon P-125) A mixture with 30 parts, the thickness of the first pressure-sensitive adhesive layer was 8 μm, and the second pressure-sensitive adhesive layer was not provided. An adhesive tape (C11) was obtained. The thickness of the fine unevenness erasing layer is 2 μm, the thickness of the roughness developing layer is 10 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 8 μm, and the thickness of the second pressure-sensitive adhesive layer is 0 μm (not present). Met. Table 2 shows the evaluation results for the obtained adhesive tape (C11).

[Comparative Example 12]
An adhesive tape (C12) was obtained in the same manner as in Comparative Example 6, except that the thickness of the roughness developing layer was 2 μm. The thickness of the fine unevenness erasing layer is 2 μm, the thickness of the roughness developing layer is 2 μm, the thickness of the base material layer is 38 μm, the thickness of the first pressure-sensitive adhesive layer is 8 μm, and the thickness of the second pressure-sensitive adhesive layer is 0 μm (not present). Met. Table 2 shows the evaluation results of the obtained adhesive tape (C12).

  As shown in Table 1, the pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape that can protect the uneven surface of a member having an uneven surface, and has both sufficient adhesiveness to the member and sufficient peelability. In addition, when the member protected by the adhesive tape is deformed by laminating or winding it, the uneven shape is not deformed, and the base material layer in the adhesive tape may be damaged. Without further changing the mechanical properties of the entire pressure-sensitive adhesive tape, it was adjusted so as to be compatible with both low haze with excellent permeability and large surface roughness that makes it difficult to see foreign objects such as fish eyes, It turns out that it is an adhesive tape. Further, the pressure-sensitive adhesive tape of the present invention can effectively protect the lens surface when a prism sheet having a plurality of triangular prisms fixed on the surface is used as a member having irregularities on the surface. It functions as a protective film, has both sufficient adhesiveness to the prism sheet and sufficient peelability, and when the prism sheet protected with the adhesive tape is in a state of lamination or long winding, It turns out that it is an adhesive tape which can suppress that a nonuniformity (press mark) arises in the external appearance of the prism sheet which stuck the adhesive tape.

  On the other hand, as shown in Table 2, in the case of the pressure-sensitive adhesive tape that does not satisfy the requirements of the pressure-sensitive adhesive tape of the present invention, sufficient adhesiveness to a member having irregularities on the surface and sufficient peelability cannot be achieved, When the member protected by the adhesive tape is deformed by lamination or long winding, the uneven shape is deformed, the substrate layer in the adhesive tape is damaged, or the mechanical properties of the entire adhesive tape vary. In other words, the low haze with excellent permeability and the large surface roughness to the extent that it is difficult to visually recognize foreign matters such as fish eyes cannot be achieved. In the case of an adhesive tape that does not satisfy the requirements of the adhesive tape of the present invention, when a prism sheet having a plurality of triangular prisms fixed on the surface is used as a member having irregularities on the surface, the lens surface is When it is not possible to protect effectively, it is impossible to achieve both sufficient adhesion to the prism sheet and sufficient releasability, or when the prism sheet protected by the adhesive tape is in a state of lamination or long winding In addition, it can be seen that unevenness (push marks) occurs in the appearance of the prism sheet to which the adhesive tape is applied.

  The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape that can protect the uneven surface of a member having unevenness on the surface, and has both sufficient adhesion to the member and sufficient peelability, and the Even when the member protected by the adhesive tape is deformed by lamination or long winding, the uneven shape is not deformed, and the base material layer in the adhesive tape is not damaged. Without changing the mechanical properties of the adhesive tape, the adhesive tape is adjusted to achieve both low haze with excellent permeability and large surface roughness that is difficult to visually recognize foreign objects such as fish eyes. When a prism sheet having a plurality of triangular prisms fixed on the surface is used as a member having irregularities on the surface, it functions as a surface protective film that can effectively protect the lens surface, and A prism sheet that has both sufficient adhesiveness to the sheet and sufficient peelability, and has the adhesive tape applied when the prism sheet protected by the adhesive tape is in a state of lamination or long winding. Since it is an adhesive tape that can suppress the occurrence of unevenness (push marks) in the appearance of the concavo-convex member, which is used in, for example, the automobile industry and the housing construction material industry, It is suitable for protecting optical members having irregularities on the surface such as a prism sheet.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Roughness expression layer 3 Fine uneven | corrugated elimination layer 21 1st adhesive layer 22 2nd adhesive layer 100 Adhesive tape

Claims (11)

A pressure-sensitive adhesive tape comprising a laminate (I) having a base material layer, a roughness developing layer, and a fine unevenness erasing layer in this order, a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer,
It has a fine unevenness elimination layer, a roughness expression layer, a base material layer, a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer in this order,
The base material layer includes a thermoplastic resin;
The roughness developing layer includes at least one resin component (A) selected from polyethylene, ethylene-vinyl acetate copolymer, propylene-based polymer, and olefin-based thermoplastic elastomer,
The fine unevenness erasing layer contains a thermoplastic resin (B),
The arithmetic average surface roughness Ra of the fine unevenness erasing layer side surface is 1.0 μm to 3.0 μm,
The laminate (I) has a haze value of 30% or less,
The storage elastic modulus of the first pressure-sensitive adhesive layer is higher than the storage elastic modulus of the second pressure-sensitive adhesive layer;
Adhesive tape. The pressure-sensitive adhesive tape according to claim 1, wherein the storage elastic modulus of the first pressure-sensitive adhesive layer is 1.0 x 10 ⁶ Pa or more and less than 1.0 x 10 ⁹ Pa at a frequency of 10 Hz and 23 ° C. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the storage elastic modulus of the second pressure-sensitive adhesive layer is 1.0 x 10 ³ Pa or more and less than 1.0 x 10 ⁶ Pa at a frequency of 10 Hz and 23 ° C.   The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the roughness developing layer has a thickness of 2 µm to 10 µm.   The pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the fine unevenness erasing layer has a thickness of 1 µm to 10 µm.   The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the roughness developing layer has two or more melting temperatures Tm in differential scanning calorimetry.   The pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the roughness developing layer contains at least one selected from a propylene-based polymer and an olefin-based thermoplastic elastomer.   The pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein the fine unevenness erasing layer has a long-chain alkyl release agent.   The pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer is a thermoplastic pressure-sensitive adhesive, and the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer is a thermoplastic pressure-sensitive adhesive. Adhesive tape.   The adhesive tape in any one of Claim 1-9 whose haze value is 30% or less.   The pressure-sensitive adhesive tape according to any one of claims 1 to 10, which is a surface protective film for a prism sheet.

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