JP2011025668A - Laminated film and pressure-sensitive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film and a pressure-sensitive adhesive tape wherein a difference between an image clarity in a lengthwise direction and an image clarity in a widthwise direction is small and hence the distortion of transmitted light is small, and desired mechanical properties are substantially free of reduction. <P>SOLUTION: The laminated film 10 includes a base material layer 1 and a surface layer 2, wherein the base material layer contains a thermoplastic resin, the surface layer contains a polyethylene and an ethylene-vinyl acetate copolymer, and the absolute value of a difference between an image clarity in the lengthwise direction of the laminated film and an image clarity in the widthwise direction of the laminated film is 10% or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminated film and an adhesive tape. More specifically, the present invention relates to a laminated film and an adhesive tape in which the difference between the image definition in the longitudinal direction and the image definition in the width direction is small.

  Generally, a film and an adhesive tape are adjusted to the haze value and surface roughness according to the purpose (for example, 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 through a T-die is brought into contact with a metal roll having a concavo-convex pattern, and the concavo-convex pattern is applied to the resin surface (film surface). There is known a method for transferring the image (for example, Patent Documents 1 and 2).

  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 that unevenness processing is also applied to the surface of the touch roll rubber for the purpose of improving the peelability of the film, and this unevenness affects the haze value of the film. Therefore, there arises a problem that it is difficult to obtain a film having a desired haze value (particularly, a medium / low haze value).

  Examples of film forming methods other than the T-die extrusion touch roll forming method include a T-die air knife forming method and an inflation air cooling forming method. However, since these methods form irregularities on the film surface only by flow deformation from when the resin is melted to when it is cooled and solidified, it is difficult to form precise irregularities on the film surface.

  Even during air-cooling molding, attempts have been made to adjust the haze value by intentionally forming a sea-island phase-separated structure using two or more components that are hardly compatible as film-forming resins. . However, in order to control the sea-island structure of the entire film and adjust the haze value and the surface roughness, it is necessary to ensure the thickness of the film accordingly, and it is difficult to reduce the film thickness. Moreover, it is necessary to adjust the composition of the material used for film formation each time according to the desired haze value and surface roughness. As a result, the mechanical properties of the entire film greatly vary with the adjustment of the haze value and the surface roughness. For this reason, it is difficult to independently adjust the mechanical properties of the entire film and the haze value and surface roughness of the film.

  In general, the film and the adhesive tape are formed by abruptly and greatly extending and deforming the film forming material. A film formed by stretching deformation tends to cause a difference in physical properties between the longitudinal direction and the width direction. In particular, the light transmission characteristics are easily affected by stretching deformation, and a film formed by stretching deformation tends to cause a difference in image definition between the longitudinal direction and the width direction. Since a film having such a difference in image sharpness causes distortion of transmitted light, for example, when used as a protective film, it is difficult to inspect the appearance of the adherend through the protective film.

  The difference in image definition depends on the film forming material, film forming conditions, and the like. For this reason, it is difficult to achieve both the reduction in the difference in image definition and the mechanical properties required for the entire film.

JP 2003-181962 A JP 2004-149639 A

  The present invention has been made to solve the above-described conventional problems. The object of the present invention is to reduce the distortion of transmitted light with a small difference between the image clarity in the longitudinal direction and the image clarity in the width direction. Another object of the present invention is to provide a laminated film and an adhesive tape in which desired mechanical properties are not substantially lowered.

The laminated film of the present invention is a laminated film having a base material layer and a surface layer, the base material layer contains a thermoplastic resin, the surface layer contains polyethylene and an ethylene-vinyl acetate copolymer, The absolute value of the difference between the image clarity in the longitudinal direction of the laminated film and the image clarity in the width direction of the laminated film is 10% or less.
In a preferred embodiment, the image clarity in the longitudinal direction of the laminated film is 20% or less, and the image clarity in the width direction is 20% or less.
In preferable embodiment, the haze value of the said laminated | multilayer film is 30%-80%.
In preferable embodiment, arithmetic mean surface roughness Ra of the said surface layer is 0.5 micrometer-2.0 micrometers.
In preferable embodiment, the thickness of the said surface layer is 2 micrometers-10 micrometers.
In a preferred embodiment, the weight ratio of the polyethylene to the ethylene-vinyl acetate copolymer is polyethylene: ethylene-vinyl acetate copolymer = 20: 80 to 80:20.
In preferable embodiment, the content rate of the structural unit derived from vinyl acetate in the said ethylene-vinyl acetate copolymer is 10 weight% or more.
In a preferred embodiment, the surface layer has two or more melting temperatures Tm in differential scanning calorimetry.
In a preferred embodiment, the polyethylene has a melt flow rate of 8 g / 10 min to 100 g / 10 min.
In a preferred embodiment, the ethylene-vinyl acetate copolymer has a melt flow rate of 0.1 g / 10 min to 7 g / 10 min.
According to another aspect of the present invention, an adhesive tape is provided. This adhesive tape has an adhesive layer on one side of the laminated film.
In a preferred embodiment, the absolute value of the difference between the image definition in the longitudinal direction and the image definition in the width direction of the pressure-sensitive adhesive tape is 10% or less.
In preferable embodiment, the image clarity of the longitudinal direction of the said adhesive tape is 20% or less, and the image clarity of the width direction is 20% or less.
In preferable embodiment, the haze value of the said adhesive tape is 30%-80%.
In a preferred embodiment, the surface layer has a long-chain alkyl release agent.

  According to the present invention, by having a surface layer containing a specific resin, it is possible to obtain a laminated film and an adhesive tape in which the difference between the image definition in the longitudinal direction and the image definition in the width direction is small and the distortion of transmitted light is small. be able to. In addition, since the surface layer of the laminated film and the adhesive tape of the present invention is very thin, the image properties in the longitudinal direction and the width direction are substantially reduced without substantially reducing the mechanical properties required for the laminated film or the entire adhesive tape. The difference from the image definition can be reduced. Furthermore, since the laminated film and the adhesive tape of the present invention are excellent in productivity, they can be obtained at low cost.

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

A. Laminated film The laminated film of the present invention has a substrate layer and a surface layer. FIG. 1 is a schematic cross-sectional view of a laminated film according to a preferred embodiment of the present invention. The laminated film 10 includes a base material layer 1 and a surface layer 2 disposed on one side or both sides (one side in the illustrated example) of the base material layer 1. The laminated film of the present invention may further have any appropriate other layer as required (not shown). The other layer may be provided at any position other than the side of the surface layer 2 where the base material layer 1 is not disposed.

  The thickness of the laminated film of 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 laminated film of the present invention, the absolute value of the difference between the image clarity in the longitudinal direction of the laminated film and the image clarity in the width direction of the laminated film is 10% or less, preferably 8% or less. More preferably, it is 5% or less. In the laminated film of the present invention, if the absolute value of the difference between the image clarity in the longitudinal direction of the laminated film and the image clarity in the width direction of the laminated film is within such a range, the light transmitted through the laminated film Distortion can be reduced. As a result, for example, when the laminated film of the present invention is used as a protective film and the appearance of the adherend on which the laminated film is pasted over the laminated film is visually inspected, the defects of the adherend can be easily and efficiently obtained. Can be detected. Moreover, when the laminated film of the present invention is used for applications requiring design properties, an excellent design can be expressed. In the present specification, “longitudinal direction” refers to the film transport direction during film formation, and “width direction” refers to the direction orthogonal to the longitudinal direction. Also, in this specification, “longitudinal image definition” means that the linear direction of the transmission part of the optical comb used for measuring the image definition is parallel to the longitudinal direction of the film. The “image definition in the width direction” means the image definition when the line direction of the transmission part of the optical comb is perpendicular to the longitudinal direction of the film. The image definition can be measured by a method according to JISK7105.

  The image definition in the longitudinal direction of the laminated film of the present invention is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 8% or less. Preferably, it is 4% to 8%. The image definition in the width direction of the laminated film of the present invention is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 8% or less. Preferably, it is 4% to 8%. In the laminated film of the present invention, when the image clarity in the longitudinal direction of the laminated film and the image clarity in the width direction of the laminated film are greater than 20%, for example, using the laminated film of the present invention as a protective film, When inspecting the appearance of an adherend on which the laminated film is pasted over the laminated film, up to defects that are not caused by the adherend (for example, defects in the laminated film, foreign matter mixed in when the laminated film is stuck) It becomes easy to detect and there exists a possibility that the test | inspection efficiency of the fault of the adherend which should be detected originally may fall.

  The haze value of the laminated film of the present invention is preferably 30% to 80%, more preferably 35% to 75%. When the haze value of the laminated film is within such a range, the laminated film has an appearance suitable for a protective film application and an appearance adjustment application. If the haze value of the laminated film is less than 30%, the desired image definition may not be obtained. The haze value can be measured by a method according to JISK7136 (2000).

A-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.

  The haze value of the base material layer is preferably 1% to 80%, more preferably 10% to 60%. When the haze value of the base material layer is in such a range, a laminated film having an appearance suitable for a protective film application and an appearance adjustment application can be obtained. When the haze value of the base material layer is smaller than 30%, a laminated film having the desired image definition may not be obtained.

  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-2. Surface Layer The thickness of the surface 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 surface layer is less than 2 μm, the desired surface roughness may be difficult to obtain, and a laminated film having a high haze value may be difficult to obtain. When the thickness of the surface layer is greater than 10 μm, the mechanical properties of the surface layer affect the mechanical properties of the laminated film and the entire adhesive tape having the surface layer, and the mechanical properties of the laminated film and the entire adhesive tape are There is a risk that it will decrease, or the handling of the laminated film and the adhesive tape will deteriorate.

  The haze value of the surface layer is preferably 30% to 80%, more preferably 35% to 75%. When the haze value of the surface layer is in such a range, a laminated film having an appearance suitable for a protective film application and an appearance adjustment application can be obtained. When the haze value of the surface layer is less than 30%, the laminated film having the desired image definition may not be obtained.

  The arithmetic average surface roughness Ra of the surface layer is preferably 0.5 μm to 2.0 μm, more preferably 0.8 μm to 1.9 μm, and further preferably 1.0 μm to 1.9 μm. When the arithmetic average surface roughness Ra of the surface layer is in such a range, a laminated film having an appearance suitable for a protective film application and an appearance adjustment application can be obtained.

  The surface layer includes polyethylene and an ethylene-vinyl acetate copolymer. Any appropriate weight ratio can be adopted as the weight ratio between the polyethylene and the ethylene-vinyl acetate copolymer depending on the desired haze value and / or surface roughness. The weight ratio (polyethylene: ethylene-vinyl acetate copolymer) is preferably 20: 80-80: 20, more preferably 30: 70-80: 20, and particularly preferably 30: 70-70: 30.

  Preferably, the polyethylene and the ethylene-vinyl acetate copolymer have different melt flow rates. If the polyethylene and the ethylene-vinyl acetate copolymer show different melt flow rates, the resin having a high melt flow rate is easily stretched and low when the surface layer forming material is molded by being stretched in a hot melt state. Since the resin is not easily stretched, a surface layer having a sea-island structure in which a resin having a high melt flow rate forms a sea portion and a resin having a low melt flow rate forms an island portion can be obtained. When the surface layer has the island portion that is hardly subjected to elongation stress and has little elongation deformation, a laminated film having a small difference between the image definition in the longitudinal direction and the image definition in the width direction can be obtained.

  The melt flow rate of the polyethylene is preferably 8 g / 10 min to 100 g / 10 min, more preferably 9 g / 10 min to 80 g / 10 min, particularly preferably 9 g / 10 min to 50 g / 10 min, and most preferably 15 g. / 10 min to 50 g / 10 min. If the melt flow rate of polyethylene is in such a range, a laminated film having a haze value and surface roughness suitable for protective film applications and appearance adjustment applications can be obtained. When the melt flow rate of polyethylene is less than 8 g / 10 min, the difference in melt flow rate between polyethylene and the ethylene-vinyl acetate copolymer is reduced, and the image clarity in the longitudinal direction and the image clarity in the width direction of the laminated film are reduced. There is a possibility that the difference with the degree becomes too large. The melt flow rate can be measured by a method according to JISK7210.

  The melt flow rate of the ethylene-vinyl acetate copolymer is preferably 0.1 g / 10 min to 7 g / 10 min, more preferably 0.2 g / 10 min to 5 g / 10 min, and particularly preferably 0.2 g / min. It is 10min-3g / 10min, Most preferably, it is 0.4g / 10min-2.8g / 10min. When the melt flow rate of the ethylene-vinyl acetate copolymer is within such a range, a laminated film having a haze value and a surface roughness suitable for protective film applications and appearance adjustment applications can be obtained. When the melt flow rate of the ethylene-vinyl acetate copolymer is larger than 7 g / 10 min, the difference in melt flow rate between the polyethylene and the ethylene-vinyl acetate copolymer is reduced, and the image clarity in the longitudinal direction of the laminated film is The difference from the image definition in the width direction may be too large.

  If the melt flow rate of the polyethylene and the ethylene-vinyl acetate copolymer is in the above range, the polyethylene has a sea part and the ethylene-vinyl acetate copolymer has an sea-island structure. A surface layer can be obtained.

  When the viscosity difference between a low viscosity resin (showing a high melt flow rate) and a high viscosity resin (showing a low melt flow rate) is small, it is difficult to obtain a clear deformation flow difference, and a sea-island structure cannot be obtained, A laminated film having a low haze and a smooth surface roughness can be obtained. On the other hand, when the viscosity difference between a low viscosity resin (showing a high melt flow rate) and a high viscosity resin (showing a low melt flow rate) is large, a clear deformation flow difference can be obtained, and the sea-island structure becomes clear. A laminated film having a high haze and a rough surface can be obtained. The target haze and surface roughness can be controlled by the difference in viscosity of the resin used. In order to obtain a rough surface roughness with high haze, it is preferable that the melting point of the high-viscosity resin having an island structure is higher than the melting point of a low-viscosity resin having a sea structure. This is because the island structure is first cooled and solidified during elongation flow, and the high-viscosity resin of the sea-forming resin is not cooled and solidified when solidified, thereby forming a clear sea-island structure.

  The surface layer preferably has two or more melting temperatures Tm in differential scanning calorimetry (DSC). Such a surface layer can be obtained by using polyethylene and ethylene-vinyl acetate copolymers having different melting points. By using polyethylene and ethylene-vinyl acetate copolymer having different melting points for the surface layer, the haze value and surface roughness of the laminated film can be adjusted by the difference in melting point, and the appearance of the laminated film can be controlled. More specifically, when the film is formed by cooling and solidifying after heat melting, the high melting point polyethylene is solidified first, and then the low melting point ethylene-vinyl acetate copolymer is solidified. When it is large, a clear sea-island structure can be obtained in the surface layer, and as a result, a laminated film having a large haze value and surface roughness can be obtained. On the other hand, when the melting point difference is small, it is difficult to obtain a surface layer having a clear sea-island structure, so that a laminated film having a small haze value and surface roughness can be 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.

  The melting point of polyethylene is preferably 100 ° C to 125 ° C, more preferably 105 ° C to 125 ° C, further preferably 110 ° C to 125 ° C, and particularly preferably 115 ° C to 120 ° C.

  The melting point of the ethylene-vinyl acetate copolymer is preferably 50 ° C to 120 ° C, more preferably 60 ° C to 120 ° C, still more preferably 70 to 120 ° C, and particularly preferably 80 to 115 ° C. Yes, most preferably 100-115 ° C.

  The difference between the melting point of the polyethylene and the melting point of the ethylene-vinyl acetate copolymer is preferably 5 ° C to 65 ° C, more preferably 10 ° C to 60 ° C, and particularly preferably 15 ° C to 50 ° C. is there. If the difference between the melting point of polyethylene and the melting point of ethylene-vinyl acetate copolymer is within such a range, a laminated film having a haze value and surface roughness suitable for protective film applications and appearance adjustment applications can be obtained. .

  The haze value and surface roughness of the laminated film of the present invention can also be adjusted by the compatibility of the polyethylene and the ethylene-vinyl acetate copolymer in the surface layer. When the compatibility between polyethylene and the ethylene-vinyl acetate copolymer is low, a clear sea-island structure can be obtained in the surface layer, so that a laminated film having a large haze value and surface roughness can be obtained. On the other hand, when the compatibility is high, it is difficult to obtain a clear sea-island structure, and thus a laminated film having a small haze value and surface roughness can be obtained. The said compatibility can be adjusted with the content rate of the structural unit derived from vinyl acetate in an ethylene-vinyl acetate copolymer, for example.

  The content ratio of the structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer is preferably 10% by weight or more, more preferably 15% by weight or more, and particularly preferably 20% by weight or more. Most preferably, it is 20 to 30% by weight. If the content ratio of the structural unit derived from vinyl acetate is in such a range, the ethylene-vinyl acetate copolymer exhibits appropriate compatibility with the polyethylene, and is a haze suitable for protective film use and appearance adjustment use. A laminated film having a value and a surface roughness can be obtained.

  Commercially available products may be used as the polyethylene and the ethylene-vinyl acetate copolymer. Specific examples of commercially available polyethylene include the trade name “Petrocene 209” manufactured by Tosoh Corporation, the trade names “Novatech LD LJ803”, “Novatech LD LC701”, and “Novatech LD LC720” manufactured by Nippon Polyethylene. Specific examples of commercially available ethylene-vinyl acetate copolymers include “Evaflex EV270” manufactured by Mitsui DuPont Polychemical Co., Ltd.

  The surface layer may contain any appropriate additive as required. As the additive that can be contained in the surface layer, for example, the additive described in the section A-1 can be used.

A-3. Other Layers The laminated film of the present invention may further have other appropriate other layers as necessary (not shown). The other layer may be provided at any position other than the side of the surface layer where the base material layer is not disposed.

  The thickness of the other layer is preferably 2 μm to 12 μm, and more preferably 5 μm to 10 μm.

  Any appropriate value can be adopted as the haze value of the other layer according to the haze value of the laminated film of the present invention.

  As said other layer, a smooth layer is mentioned, for example. For example, when the laminated film has a surface layer on one side of the substrate layer, the smooth layer can be used by being disposed on the side of the substrate layer where the surface layer is not disposed.

  Any appropriate material can be adopted as the material constituting the smooth layer. As a material constituting the smooth layer, for example, a polyolefin resin such as polyethylene, polypropylene, or TPO can be employed. Specifically, various thermoplastic resins such as various polyethylenes having a low density to a high density and various polypropylenes such as isotactic, atactic, and syndiotactic polypropylenes can be used. In addition to polyolefin resins, the main components are modified α-olefins, copolymers of α-olefins with various vinyl compounds such as vinyl acetate and methacrylate, polyamides, polyesters, polycarbonates, polyurethanes, polyvinyl chlorides, and the like. Such a thermoplastic resin may be employed. These materials may be used alone or in combination of two or more.

A-4. Formation method of laminated film The laminated film can be obtained by any appropriate formation method. Typically, a method of co-extruding the base material layer, the surface layer, and another layer as necessary may be mentioned. The co-extrusion method can be performed according to the inflation method, the T-die method, or the like, using an extruder and a co-extrusion die for each layer forming material. Other manufacturing methods include, for example, a method in which a base material layer, a surface layer, and, if necessary, other layers are bonded to each other using any appropriate adhesive by a calender molding method. .

B. Adhesive tape The adhesive tape of this invention has the laminated | multilayer film of this invention, and the adhesive layer arrange | positioned at the one side of the said laminated | multilayer film. FIG. 2 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 laminated film 10 and an adhesive layer 20 arranged on the side where the surface layer 2 of the laminated film 10 is not arranged. The laminated film 10 constituting the pressure-sensitive adhesive tape of the present invention is the laminated film of the present invention described above, and includes the base material layer 1 described in the section A-1 and the surface layer 2 described in the section A-2. .

  The surface layer used for the pressure-sensitive adhesive tape of the present invention preferably further contains a long-chain alkyl release agent. If the surface layer contains a long-chain alkyl release agent, it is possible to prevent sticking between the surface layer and the pressure-sensitive adhesive layer in a state where the pressure-sensitive adhesive tapes overlap each other, for example, in a roll form. Moreover, since it is not necessary to cover a surface layer with a separator layer, the adhesive tape which has a desired haze value and surface roughness can be obtained easily.

  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 carbon number of the alkyl group is in such a range, a surface 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 such 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. Is mentioned. 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 surface layer having excellent peelability can be obtained.

  The long-chain alkyl release agent is kneaded into the surface layer when the laminated film or the adhesive tape is coextruded. The content of the long-chain alkyl release agent in the surface 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 to 20% by weight. % 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.

  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 image definition in the longitudinal direction of the pressure-sensitive adhesive tape of the present invention is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 8% or less. Preferably, it is 4% to 8%. The image definition in the width direction of the pressure-sensitive adhesive tape of the present invention is preferably 20% or less, more preferably 10% or less, particularly preferably 8% or less, and most preferably 4% to 8%. . In the pressure-sensitive adhesive tape of the present invention, when the image clarity in the longitudinal direction of the pressure-sensitive adhesive tape and the image clarity in the width direction of the pressure-sensitive adhesive tape are larger than 20%, for example, using the pressure-sensitive adhesive tape of the present invention as a protective film, Defects not caused by the adherend when the adherend with the adhesive tape pasted over the adhesive tape is inspected (for example, defects in the adhesive tape, foreign matter mixed in when the adhesive tape is pasted) May be easily detected, and the inspection efficiency of the defect of the adherend to be detected may be reduced. The pressure-sensitive adhesive tape showing such image definition can be obtained by providing the pressure-sensitive adhesive tape with the surface layer of the present invention.

  In the pressure-sensitive adhesive tape of the present invention, the absolute value of the difference between the image clarity in the longitudinal direction of the pressure-sensitive adhesive tape and the image clarity in the width direction of the pressure-sensitive adhesive tape is preferably 10% or less, more preferably 8%. Or less, more preferably 5% or less. In the pressure-sensitive adhesive tape of the present invention, if the absolute value of the difference between the image clarity in the longitudinal direction of the pressure-sensitive adhesive tape and the image clarity in the width direction of the pressure-sensitive adhesive tape is within such a range, the light transmitted through the pressure-sensitive adhesive tape Distortion can be reduced. As a result, for example, when using the pressure-sensitive adhesive tape of the present invention as a protective film and visually inspecting the adherend on which the pressure-sensitive adhesive tape is pasted over the pressure-sensitive adhesive tape, the defects of the adherend can be easily and efficiently obtained. Can be detected. Moreover, when the adhesive tape of this invention is used for the use for which designability is requested | required, the outstanding design can be expressed. The pressure-sensitive adhesive tape showing such a difference in image definition can be obtained by providing the pressure-sensitive adhesive tape with the surface layer of the present invention.

  The haze value of the pressure-sensitive adhesive tape of the present invention is preferably 30% to 80%, more preferably 35% to 75%. If the haze value of an adhesive tape is such a range, this adhesive tape has the external appearance suitable for a protective film use and an external appearance adjustment use. When the haze value of the pressure-sensitive adhesive tape is less than 30%, the desired image definition may not be obtained. The pressure-sensitive adhesive tape exhibiting such a haze value can be obtained when the pressure-sensitive adhesive tape includes the surface layer of the present invention.

B-1. Pressure-sensitive adhesive layer The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 300 μm, more preferably 4 μm to 100 μm, and particularly preferably 5 μm to 50 μm.

  The haze value of the pressure-sensitive adhesive layer is preferably 1% to 80%, more preferably 10% to 60%. If the haze value of an adhesive layer is such a range, the adhesive tape which has an external appearance suitable for a protective film use and an external appearance adjustment use can be obtained. When the haze value of the pressure-sensitive adhesive layer is less than 1%, the pressure-sensitive adhesive tape having the desired image definition may not be obtained.

  Arbitrary appropriate adhesive can be employ | adopted for the adhesive which comprises the said 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; ethylenic double bond of styrene-based random copolymer such as styrene-butadiene rubber (SBR) is hydrogenated And the like. Examples of commercially available products include “G1657” (styrene elastomer) manufactured by Kraton Polymer. 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 is likely to occur. When there is more content rate of a styrene block structure than 40 weight%, an adhesive layer becomes hard and there exists a possibility that favorable adhesiveness cannot be obtained with respect to a rough surface.

  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%. When the content ratio of the structural unit derived from butylene is in such a range, a pressure-sensitive adhesive layer that is excellent in wettability and adhesiveness and can adhere well to a rough surface 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.

  The said adhesive layer can contain another component as needed. Examples of other components include olefin resins; silicone resins; liquid acrylic copolymers; polyethyleneimines; fatty acid amides; phosphate esters; The type, number and amount of other components contained in the pressure-sensitive adhesive layer can be appropriately set according to the purpose. Examples of the additive include tackifiers; softeners; anti-aging agents; hindered amine light stabilizers; ultraviolet absorbers; fillers or pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide; Is mentioned.

  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, it is 0-40 weight part with respect to 100 weight part of resin materials which form an adhesive, More preferably, it is 0-30 weight part, More preferably, it is 0-10 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 adhesion 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, it may cause the material transfer from the adhesive layer to the adherend or heavy peeling, while if the molecular weight of the softening agent becomes too large, the effect of improving the adhesive strength may be caused. Since there exists a tendency to become scarce, the number average molecular weight of a softening agent becomes like this. Preferably it is 5000-100000, More preferably, it is 10000-50000.

  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, preferably 100 parts by weight or less with respect to 100 parts by weight of the resin material forming the adhesive, More preferably, it is 20 weight part or less, More preferably, it is 10 weight part or less. When the addition amount of the softening agent exceeds 40 parts by weight with respect to 100 parts by weight of the resin material forming the pressure-sensitive adhesive, the adhesive residue becomes remarkable under outdoor exposure in a high temperature environment.

  The 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.

B-2. 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 substrate layer and the surface layer constituting the laminated film of the present invention, a method of co-extruding the pressure-sensitive adhesive layer (manufacturing method 1), and the surface layer of the laminated film. Method of hot-melt coating the pressure-sensitive adhesive on the side where the adhesive is not disposed (Manufacturing method 2), Organic solvent coating liquid or pressure-sensitive adhesive in which the pressure-sensitive adhesive is dissolved on the side where the surface layer of the laminated film is not disposed The method (manufacturing method 3) etc. which apply | coat the emulsion liquid which water-dispersed in water are mentioned. In addition, the laminated | multilayer film in the manufacturing methods 2 and 3 can be obtained by the method demonstrated by A-3 term.

  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.

  In the production method 1, the co-extrusion method is performed by using an extruder and a co-extrusion die for the base layer forming material, the surface layer forming material, and the pressure-sensitive adhesive layer forming material, respectively. It can be done according to this.

  When manufacturing an adhesive tape by the said manufacturing method 2 or 3, Preferably, an easily bonding process is given to the surface by which the adhesive is coated, ie, the surface where the said surface layer of the said laminated | multilayer film is not arrange | positioned. . 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 said adhesive which comprises the said adhesive layer, the said rubber adhesive, an acrylic adhesive, or a silicone adhesive is used preferably.

  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.

(1) Image clarity Measured with a transmission type optical comb of 2 mm using “ICM-1” manufactured by Suga Test Instruments Co., Ltd. based on JISK7105. The image definition in the longitudinal direction was measured such that the longitudinal direction of the laminated film or the adhesive tape and the line direction of the transmission part of the optical comb were parallel. The image definition in the width direction was measured so that the longitudinal direction of the laminated film or the adhesive tape and the line direction of the transmission part of the optical comb were orthogonal to each other. The image definition is calculated by: Image definition (%) = (M−m) / (M + m) × 100 (M: highest wave height, m: lowest wave height).
(2) 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.
(3) Haze value The haze value was measured using a haze meter HM-150 (manufactured by 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.

[Example 1]
The following compounds were prepared as a surface layer forming material, a base material layer forming material, and a smooth layer forming material.
Surface layer forming material: Low-density polyethylene (manufactured by Tosoh Corporation: Petrocene 209; melt flow rate (MFR) = 45 (190 ° C., 2.16 kgf)) and ethylene-vinyl acetate copolymer (Mitsui DuPont) Made by Polychemical Co., Ltd .: EVAFLEX EV270; MFR = 1.0 (190 ° C., 2.16 kgf); Mixture with 50 parts of vinyl acetate (VA) content 28 wt% Base material layer forming material: Block polypropylene (Made by Sun Aroma: PF380A)
Smooth layer forming material: Low density polyethylene (Nippon Polyethylene: Novatec LD LC720)
Said material was shape | molded by T-die melt coextrusion, and the laminated film (1) provided with a surface layer, a base material layer, and a smooth layer in this order was obtained. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results for the obtained laminated film (1).

[Example 2]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead, a mixture of 80 parts of low-density polyethylene (manufactured by Tosoh Corp .: Petrocene 209) and 20 parts of an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) is used. A laminated film (2) was obtained in the same manner as in Example 1 except that. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results for the obtained laminated film (2).

[Example 3]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead, a mixture of 70 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 30 parts of ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) is used. A laminated film (3) was obtained in the same manner as in Example 1 except that. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results of the obtained laminated film (3).

[Example 4]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead, a mixture of 60 parts of low density polyethylene (Tosoh Corp .: Petrocene 209) and 40 parts of ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) is used. A laminated film (4) was obtained in the same manner as in Example 1 except that. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results of the obtained laminated film (4).

[Example 5]
As a surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd .: Novatec LD LJ803; MFR = 22 (190 ° C., 2.16 kgf) ) A laminated film (5) was obtained in the same manner as in Example 1 except that 50 parts were used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results for the obtained laminated film (5).

[Example 6]
The following compounds were prepared as a surface layer forming material, a base material layer forming material, and an adhesive layer forming material.
Surface layer forming material: 50 parts of low-density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270), and long chain Alkyl release agent (Ashio Sangyo Co., Ltd .: Aciolesin RA95HS (fully saponified polyvinyl octadecyl carbamate release agent)) 10 parts mixture Base material layer forming material: Block polypropylene (San Allomer: PF380A)
Adhesive layer forming material: 75 parts of styrene-ethylene-butylene-styrene block copolymer (SEBS) (manufactured by Kraton Polymer Co., Ltd .: G1657) and 25 parts of tackifier (manufactured by Arakawa Chemical Industries, Ltd .: Alcon P-125) The above material was molded by T-die melt coextrusion to obtain a pressure-sensitive adhesive tape (1) comprising a surface layer, a base material layer and a pressure-sensitive adhesive layer in this order. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results for the obtained adhesive tape (1).

[Example 7]
As the surface layer forming material, 80 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) is used instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209). Instead of 50 parts of a polymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270), 20 parts of an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) was used. Except for the above, an adhesive tape (2) was obtained in the same manner as in Example 6. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (2).

[Example 8]
As a surface layer forming material, 70 parts of low-density polyethylene (Tosoh Corp .: Petrocene 209) is used instead of 50 parts of low-density polyethylene (Tosoh Corp .: Petrocene 209). Instead of 50 parts of a polymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270), 30 parts of an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) was used. Except for the above, an adhesive tape (3) was obtained in the same manner as in Example 6. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (3).

[Example 9]
As the surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), 60 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) is used, and ethylene-vinyl acetate is used. Instead of 50 parts of a polymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270), 40 parts of an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) was used. Except for the above, an adhesive tape (4) was obtained in the same manner as in Example 6. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (4).

[Example 10]
Example 6 except that 50 parts of low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd .: Novatec LD LJ803) was used instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) as the surface layer forming material. In the same manner as above, an adhesive tape (5) was obtained. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results for the obtained adhesive tape (5).

[Comparative Example 1]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead, a mixture of 10 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 90 parts of ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) is used. A laminated film (C1) was obtained in the same manner as in Example 1 except that. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results for the obtained laminated film (C1).

[Comparative Example 2]
As a surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), low density polyethylene (manufactured by Nippon Polyethylene Corporation: Novatec LD LC720); MFR = 9.4 (190 ° C., 2. 16 kgf)) A laminated film (C2) was obtained in the same manner as in Example 1 except that 50 parts were used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results of the obtained laminated film (C2).

[Comparative Example 3]
As a surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), low density polyethylene (manufactured by Tosoh Corporation: Petrocene 217); MFR = 4.5 (190 ° C., 2 .16 kgf)) A laminated film (C3) was obtained in the same manner as in Example 1 except that 50 parts were used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. The evaluation results for the obtained laminated film (C3) are shown in Table 1.

[Comparative Example 4]
As a surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), low density polyethylene (manufactured by Nippon Polyethylene Corporation: Novatec LD LC701; MFR = 14 (190 ° C., 2.16 kgf) ) A laminated film (C4) was obtained in the same manner as in Example 1 except that 50 parts were used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results of the obtained laminated film (C4).

[Comparative Example 5]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead of 50 parts of low density polyethylene (Nippon Polyethylene: Novatec LD LC720) and ethylene-vinyl acetate copolymer (Nippon Polyethylene Co., Ltd .: Novatec EVA LV211; MFR = 0.3 (190 ° C., 2 .16 kgf); a laminated film (C5) was obtained in the same manner as in Example 1 except that a mixture with 50 parts of VA content of 6% by weight was used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. Table 1 shows the evaluation results of the obtained laminated film (C5).

[Comparative Example 6]
As a surface layer forming material, a mixture of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) and 50 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270) Instead of 50 parts of low density polyethylene (Nippon Polyethylene: Novatec LD LC720) and ethylene-vinyl acetate copolymer (Tosoh Corporation: Ultrasen 627; MFR = 0.8 (190 ° C., 2. 16 kgf); a laminated film (C6) was obtained in the same manner as in Example 1 except that a mixture with 50 parts of VA content of 20% by weight was used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. The evaluation results for the obtained laminated film (C6) are shown in Table 1.

[Comparative Example 7]
A laminated film (C7) was obtained in the same manner as in Example 1 except that the surface layer forming material ethylene-vinyl acetate copolymer was not used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the smooth layer was 7 μm. The evaluation results for the obtained laminated film (C7) are shown in Table 1.

[Comparative Example 8]
As the surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), 10 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) is used. Instead of 50 parts of a polymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270), 90 parts of an ethylene-vinyl acetate copolymer (Mitsui DuPont Polychemical Co., Ltd .: Everflex EV270) was used. Except for this, an adhesive tape (C1) was obtained in the same manner as in Example 6. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C1).

[Comparative Example 9]
Example 6 except that 50 parts of low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd .: Novatec LD LC720) was used instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) as the surface layer forming material. In the same manner as above, an adhesive tape (C2) was obtained. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results for the obtained adhesive tape (C2).

[Comparative Example 10]
Example except that 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 217) was used instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209) as the surface layer forming material. In the same manner as in Example 6, an adhesive tape (C3) was obtained. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results for the obtained adhesive tape (C3).

[Comparative Example 11]
As a surface layer forming material, instead of 50 parts of low density polyethylene (manufactured by Tosoh Corporation: Petrocene 209), 50 parts of low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd .: Novatec LD LC720) was used, and ethylene-vinyl acetate copolymer was used. Except for using 50 parts of an ethylene-vinyl acetate copolymer (manufactured by Nippon Polyethylene Co., Ltd .: Novatec EVA LV211) instead of 50 parts of a combined product (Mitsui DuPont Polychemical Co., Ltd .: EVAFLEX EV270), In the same manner as in Example 6, an adhesive tape (C4) was obtained. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C4).

[Comparative Example 12]
An adhesive tape (C5) was obtained in the same manner as in Example 6 except that the surface layer forming material ethylene-vinyl acetate copolymer was not used. The thickness of the surface layer was 2 μm, the thickness of the base material layer was 38 μm, and the thickness of the pressure-sensitive adhesive layer was 7 μm. Table 2 shows the evaluation results of the obtained adhesive tape (C5).

  As is clear from Tables 1 and 2, the laminated film and the adhesive tape of the present invention have a small absolute value of the difference between the image sharpness in the longitudinal direction and the image sharpness in the width direction. Moreover, since the surface layer is very thin, it does not affect the mechanical properties of the entire laminated film or adhesive tape.

  The laminated film and the pressure-sensitive adhesive tape of the present invention can be widely used in, for example, protection use, appearance adjustment use, decoration use, label use and the like in electronic component manufacturing, structural use, and automobile use.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Surface layer 10 Laminated film 20 Adhesive layer 100 Adhesive tape

Claims (15)

A laminated film having a base layer and a surface layer,
The base material layer includes a thermoplastic resin;
The surface layer comprises polyethylene and an ethylene-vinyl acetate copolymer;
The absolute value of the difference between the image clarity in the longitudinal direction of the laminated film and the image clarity in the width direction of the laminated film is 10% or less,
Laminated film.   The laminated film according to claim 1, wherein the image definition in the longitudinal direction is 20% or less and the image definition in the width direction is 20% or less.   The laminated film according to claim 1 or 2, wherein the haze value is 30% to 80%.   The laminated film according to any one of claims 1 to 3, wherein an arithmetic average surface roughness Ra of the surface layer is 0.5 µm to 2.0 µm.   The laminated film according to any one of claims 1 to 4, wherein the surface layer has a thickness of 2 µm to 10 µm.   The laminate according to any one of claims 1 to 5, wherein a weight ratio of the polyethylene and the ethylene-vinyl acetate copolymer is polyethylene: ethylene-vinyl acetate copolymer = 20: 80 to 80:20. the film.   The laminated film according to any one of claims 1 to 6, wherein a content ratio of a structural unit derived from vinyl acetate in the ethylene-vinyl acetate copolymer is 10% by weight or more.   The laminated film according to any one of claims 1 to 7, wherein the surface layer has two or more melting temperatures Tm in differential scanning calorimetry.   The laminated film according to any one of claims 1 to 8, wherein the polyethylene has a melt flow rate of 8 g / 10 min to 100 g / 10 min.   The laminated film according to any one of claims 1 to 9, wherein a melt flow rate of the ethylene-vinyl acetate copolymer is 0.1 g / 10 min to 7 g / 10 min.   The adhesive tape which has an adhesive layer on the one side of the laminated | multilayer film in any one of Claim 1-10.   The pressure-sensitive adhesive tape according to claim 11, wherein the absolute value of the difference between the image definition in the longitudinal direction and the image definition in the width direction is 10% or less.   The pressure-sensitive adhesive tape according to claim 11 or 12, wherein the image definition in the longitudinal direction is 20% or less and the image definition in the width direction is 20% or less.   The adhesive tape in any one of Claim 11-13 whose haze value is 30%-80%.   The pressure-sensitive adhesive tape according to any one of claims 11 to 14, wherein the surface layer has a long-chain alkyl release agent.

Images