JP2019126999A - Laminated film - Google Patents

Abstract

To propose a novel laminated film for surface protection, which can be used for surface protection applications of various adherends, does not peel off when there is no need to do so, and, when necessary, can peel off smoothly without breakage.SOLUTION: Proposed is a laminated film having an adhesive layer laminated on one surface of a polyester film, where a thickness of the adhesive layer is 100 nm to 9,000 nm, a surface roughness (S5p) of the adhesive layer surface is 10 nm to 1,000 nm, and a logarithmic decrement at 30°C, as measured by a rigid body pendulum tester on the adhesive layer surface, is in a range of 0.01 to 0.10.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film, and more specifically to a laminated film for surface protection provided with an adhesive layer (referred to as “peelable adhesive layer”) that can be peeled off from an adherend after sticking.

Conventionally, in order to protect the surface of the product from contamination, damage, etc. during processing, transportation, storage and assembly of various products, a surface protective film used by sticking to the surface of the product has been used. It is done.
This type of surface protective film has a peelable adhesive layer on one side of the substrate, and the surface of the product is adhered to the product by the substrate by sticking the surface protective film to the product via the adhesive layer. Generally used to protect against contamination, damage, etc.

With respect to this type of surface protective film, if the adhesive force of the adhesive layer is too low, the surface protective film may be lifted during processing and transportation, which may cause problems. Therefore, the surface protection film attached to the adherend may be required to have a peeling force at the time of peeling not less than a predetermined value so that unnecessary peeling does not occur due to an external force acting on the periphery thereof. is there.
On the other hand, with the spread of automation (mechanization) of the peeling process, it is also a required characteristic that peeling by a machine can be performed smoothly. Therefore, when peeling a surface protection film, for example with a peeling apparatus for productivity improvement, it may be required that peeling power is low.
Moreover, when peeling a surface protection film from a to-be-adhered body, the part which peels off smoothly, and the part which does not peel easily arise, and the phenomenon of what peels while making a noise called burring, what is called zipping peeling may generate | occur | produce. Therefore, as described above, it is preferable that the load applied to the peeling apparatus can be reduced also in terms of production facilities such as product quality assurance and the peeling apparatus.

As measures against the above-mentioned problems, various proposals have been made regarding the method of adjusting the peeling force of the surface protective film. For example, methods have been proposed for adjusting the properties of the material that constitutes the adhesive layer. Specifically, by mixing a low Tg polymer having tackiness and a high Tg polymer having suppressed tackiness, it has tackiness that does not cause floating or peeling, and good releasability. A pressure-sensitive adhesive for a protective film is disclosed (Patent Document 1, Patent Document 2).
Moreover, the adhesive for protective films which secures the peelability of an adhesive is disclosed by combining a crosslinking agent and a crosslinking catalyst with the polymer which comprises an adhesive layer, and raising a crosslinking density as another method (patent document) 3, Patent Document 4).

JP 2005-146151 A JP 2009-221324 A Japanese Patent Laid-Open No. 2005-200540 JP-A-2006-199762

The laminated film for surface protection provided with a peelable adhesive layer that has been disclosed in the past has low adhesiveness, and in particular, the adhesiveness at low temperature is not sufficient, so that the adherence to the adherend becomes insufficient. There was a case. However, in order to solve the problem, for example, if it is attempted to increase the adhesive strength by increasing the crosslink density of the polymer constituting the adhesive layer, it becomes difficult to adjust the delicate adhesive force, or the crosslinking progresses with time. Sometimes stick to an adherend.
In addition, the product might be broken due to the strength of stress generated when peeling the film.

  Therefore, the problem to be solved by the present invention is that it can be used for surface protection of various adherends, and is not peeled off when it is not necessary to peel off, such as when transporting the product. When it is necessary to unwind or rewind from the wound state, it can be peeled smoothly without being damaged, and the adherend may be damaged by the strength of the stress generated when peeling the film. It is an object of the present invention to provide a new peelable tacky surface protection laminated film.

  The present invention is a laminated film in which an adhesive layer is laminated on one side of a polyester film, the thickness of the adhesive layer is 100 nm or more and 9000 nm or less, and the surface roughness (S5p) of the surface of the adhesive layer is 10 nm or more and 1,000 nm. There is proposed a laminated film characterized in that the logarithmic decay rate at 30 ° C. measured by a rigid pendulum type physical property tester on the adhesive layer surface is in the range of 0.01 or more and 0.10 or less.

The laminated film proposed by the present invention protects the surface of the product from contamination, damage or the like by releasably attaching the polyester film to various products (also referred to as "adherend") through the adhesive layer. can do.
In addition, the laminated film proposed by the present invention has a thin adhesive layer and has a logarithmic decay rate (30 ° C.) on the surface of the adhesive layer in the range of 0.01 to 0.10. When it is necessary such as when peeling at a stretch or when rewinding from a wound state, it can be peeled smoothly without breakage. On the other hand, when the peeling force is applied at a low speed, for example, when the product is transported, adhesion can be made without peeling from the adherend.
In the laminated film proposed by the present invention, furthermore, the surface roughness (S5p) of the adhesive layer surface is 10 nm or more and 1,000 nm or less, so the adherend is broken by the strength of the stress generated when peeling the film. Can be prevented. Therefore, it can be effectively used as a laminated film for protecting the surface of a thin optical member such as a glass plate or a prism sheet having a moth-eye structure.

  Next, the present invention will be described based on an embodiment. However, the present invention is not limited to the embodiments described below.

<This laminated film>
The laminated film (referred to as “the present laminated film”) according to an example of the embodiment of the present invention is a laminated film in which an adhesive layer is laminated on one side of a polyester film.

As long as the adhesion layer is laminated | stacked on the single side | surface of the polyester film, the other structure is arbitrary for this laminated film. For example, it is also possible to laminate an antistatic layer on the side opposite to the side on which the adhesive layer of the polyester film is laminated.
Moreover, this laminated | multilayer film can be set as the structure which does not laminate | stack a release film on the surface of the adhesion layer especially the structure which does not laminate | stack a release film, for example. In general, the surface protective film is generally laminated with a release film on the surface of the pressure-sensitive adhesive layer, for example, bonded to the release film to protect the pressure-sensitive adhesive layer. On the other hand, as described above, the laminated film can be smoothly peeled off without being damaged when necessary, for example, when it is rewound from a wound state. For example, it can be wound as it is to form a wound body.

<Polyester film>
The polyester film in this laminated film is preferably one that can be used as a surface protective film that can protect the surface of the product.

(Polyester film)
The polyester film may have a single layer configuration or a multilayer configuration, and may have a multilayer of two layers, three layers, four layers or more, and is not particularly limited.

The polyester constituting the main component resin of the polyester film may be a homopolyester or a copolyester. In this case, the “main component resin” indicates a resin having the highest content among the resins constituting the polyester film.
When the polyester constituting the main component resin of the polyester film is a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred.
Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol and 1,4-cyclohexanedimethanol.
A polyethylene terephthalate etc. can be illustrated as a typical polyester.

  On the other hand, when it consists of copolymerized polyester, 1 type, or 2 or more types, such as isophthalic acid, phthalic acid, terephthalic acid, 2, 6- naphthalene dicarboxylic acid, sebacic acid, can be mentioned as the dicarboxylic acid component, and glycol As a component, 1 type (s) or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, can be mentioned.

  There is no restriction | limiting in particular as a polymerization catalyst of the said polyester, A conventionally well-known compound can be used, For example, a titanium compound, a germanium compound, an antimony compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned. Can do. Among these, titanium compounds and germanium compounds are preferable because they have high catalytic activity, can be polymerized in a small amount, and the amount of metal remaining in the film is small, so that the brightness of the film is increased. Furthermore, since a germanium compound is expensive, it is more preferable to use a titanium compound.

(particle)
The polyester film preferably contains particles mainly for the purpose of imparting slipperiness, preventing scratches in each step, and adjusting the surface roughness of the adhesive layer surface.

  The kind of the particle is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, Examples thereof include inorganic particles such as kaolin, aluminum oxide and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin and benzoguanamine resin. Furthermore, precipitated particles in which a part of a metal compound such as a catalyst is precipitated or finely dispersed can be used during the polyester production process.

  The shape of the particles is not particularly limited. For example, it may be spherical, massive, rod-like, flat or the like. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as needed.

The average particle diameter of the particles is preferably 0.01 μm to 5 μm, in particular, 0.1 μm or more or 4 μm or less, from the viewpoints of imparting lubricity, preventing scratching, adjusting the surface roughness of the adhesive layer surface, etc. Among these, more preferably 1 μm or more or 3 μm or less.
The average particle diameter of the particles can be determined as an average value of the diameters of the particles measured by SEM observation of 10 or more particles. At that time, in the case of non-spherical particles, the average value of the longest diameter and the shortest diameter can be measured as the diameter of each particle.

  The content of the particles in the polyester film is preferably 0.0003 to 5% by mass from the viewpoint of achieving both the slipperiness and transparency of the film, and more preferably 0.1% by mass or more or 3% by mass or less. It is more preferable that it is 0.3 mass% or more or 2 mass% or less among these.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be employed. For example, it can be added at any stage of producing the polyester constituting each layer. Preferably, it is added after completion of the esterification or transesterification reaction.

  The polyester film can contain conventionally known additives as required. For example, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a dye, a pigment, an ultraviolet absorber and the like can be added.

(Thickness)
The thickness of the polyester film is not particularly limited as long as the film can be formed into a film. It is preferably 9 μm to 100 μm, more preferably 12 μm or more and 75 μm or less, and particularly preferably 25 μm or more or 50 μm or less.

(Stretching)
The polyester film may be an unstretched film, a uniaxially stretched film, or a biaxially stretched film. Among these, a biaxially stretched film is preferable.

(Production method)
Next, a production example of a polyester film will be specifically described. However, the present invention is not limited to the following production examples.

First, a method is preferred in which pellets obtained by drying a polyester raw material are extruded as a molten sheet from a die using an extruder and cooled and solidified with a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method can be preferably employed.
Next, it is preferable to biaxially stretch the obtained unstretched sheet. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, it is stretched in the direction orthogonal to the stretching direction of the first stage. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Then, heat treatment is subsequently performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In said extending | stretching, the method of performing extending | stretching of one direction in two or more steps is also employable. In that case, it is preferable to carry out so that the draw ratio of two directions finally becomes the said range, respectively.

  Simultaneous biaxial stretching can also be employed for polyester film production. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in area ratio. Then, a stretched oriented film can be obtained by performing a heat treatment at a temperature of 170 to 250 ° C. under tension or under relaxation within 30%. With respect to the simultaneous biaxial stretching apparatus adopting the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

<Adhesive layer>
The adhesive layer preferably contains at least one of acrylate compounds as a main component resin in order to improve the adhesion with a polyester film or an adherend as a base material.
Here, the “main component resin” indicates a resin having the highest content among the resins constituting the adhesive layer.

(Acrylate compound)
As the above-mentioned acrylate compound, conventionally known ones can be used. Examples thereof include acrylate compounds having a monofunctional (meth) acrylate group, a bifunctional (meth) acrylate group, a polyfunctional (meth) acrylate group, a vinyl group, an allyl group, and the like.
The expression “(meth) acrylate compound” represents “acrylate compound and methacrylate compound”.

  Examples of the monofunctional (meth) acrylate include methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and cyclohexyl (meth) acrylate , Alkyl (meth) acrylate such as isobornyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as hydroxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxy Examples include alkoxyalkyl (meth) acrylates such as ethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, etc. Kill.

  Examples of the bifunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol. Alkanediol di (meth) acrylates such as di (meth) acrylate and tricyclodecanedimethylol di (meth) acrylate, bisphenols such as bisphenol A ethylene oxide modified di (meth) acrylate and bisphenol F ethylene oxide modified di (meth) acrylate Examples include modified di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, urethane di (meth) acrylate, and epoxy di (meth) acrylate. Kill.

  Examples of the polyfunctional (meth) acrylate include dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri ( And (meth) acrylate, tetramethylolmethaneethylene oxide-modified tetra (meth) acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, and the like.

  The above-mentioned monofunctional (meth) acrylate group, bifunctional (meth) acrylate group, polyfunctional (meth) acrylate group, vinyl group, allyl group and the like may be used alone or in combination of two or more. Also good. Of these (meth) acrylate compounds, preferably a bifunctional (meth) acrylate and a polyfunctional (meth) acrylate, more preferably a polyfunctional (meth) acrylate, from the viewpoint of improving adhesion.

  The acrylate compound contained in the adhesive layer of the present laminated film has a uniform molecular weight and composition, and since the generation of low molecular weight components is suppressed, the cohesive force of the adhesive layer is ensured, and the adhesive The acrylate compound obtained by living polymerization can be mentioned as a preferable example from the point that the contamination by the remainder is also reduced.

As an acrylate compound obtained by living polymerization, for example,
General formula (I): AB
(Wherein, A represents a methacrylic acid alkyl ester polymer block and B represents an acrylic acid alkyl ester polymer block), and an acrylic diblock copolymer represented by:
General formula (II); C1-D-C2
(In the formula, C1 and C2 each independently represent a methacrylic acid alkyl ester polymer block, and D represents an acrylic acid alkyl ester polymer block. The polymer block C1 and the polymer block C2 have a weight average molecular weight. The composition of the alkyl methacrylates forming each polymer block may be the same or different, and the acrylic triblock copolymers represented by

  These acrylic diblock copolymers and / or acrylic triblock copolymers contained in the adhesive layer of the present laminated film may be used singly or as a mixture of two or more.

  The polymer block A and polymer block B constituting the acrylic diblock copolymer, and the polymer block C1, polymer block C2 and polymer block D constituting the acrylic triblock copolymer are included in the present invention. Other monomer units may be included as long as the effect of is not impaired.

The production method of the acrylic diblock copolymer and acrylic triblock copolymer that can be used for the pressure-sensitive adhesive of the laminated film is not particularly limited, and can be produced by employing a production method according to a known method. For example, a method of living polymerizing monomers constituting each polymer block is generally used.
For example, the method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound can increase the purity of the acrylic block copolymer and easily control the molecular weight and composition ratio. It can be mentioned as a preferred production method.

  Further, among acrylate compounds obtained by living polymerization, acrylate compounds obtained by living radical polymerization using an organic tellurium polymerization initiator also have a point having uniform molecular weight and composition, and generation of low molecular weight components is suppressed. Since the cohesive force of an adhesion layer is ensured by the point and adhesive residue is also reduced, it can mention as a preferable example among the acrylate compounds which can be used for the adhesion layer of this laminated film.

In the adhesive layer, a binder resin may be used in combination from the viewpoint of improving the coating appearance, transparency, and adhesion.
Specific examples of the binder resin include, for example, polyurethane resin, polyester resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkylene imine, methyl cellulose, hydroxycellulose, starches, etc. be able to. These may be used alone or in combination.

  The term “binder resin” as used herein refers to a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). Is a high molecular compound of 1,000 or more and a polymer having a film-forming property.

  The content of the binder resin in the adhesive layer is usually 20% by mass to 80% by mass, preferably 30% by mass to 70% by mass, and more preferably 40% by mass to 60% by mass. When the content of the binder resin satisfies the above range, both good adhesion to the adherend and coating strength can be achieved.

(Crosslinking agent)
For the purpose of adjusting the adhesive strength of the adhesive layer, the adhesive layer may contain a cross-linking agent as necessary.
Specific examples of the crosslinking agent include oxazoline compounds, isocyanate compounds, epoxy compounds, melamine compounds, carbodiimide compounds, and the like. Among them, it is more preferable to use at least one of an oxazoline compound or an isocyanate compound from the viewpoint of improving adhesion.

  The content of the cross-linking agent in the adhesive layer is preferably 10% by mass to 70% by mass, especially 20% by mass or more and 60% by mass or less, and more preferably 25% by mass or more or 50% by mass or less. Is more preferable. If the content of the crosslinking agent is in the above-mentioned range, good adhesion with the opposite adherend tends to be obtained.

(Polymerization initiator)
If necessary, a polymerization initiator (also referred to as “crosslinking initiator”) may be used in combination.
Examples of the polymerization initiator include a thermal crosslinking initiator (also referred to as a "thermosetting agent"), a photocrosslinking initiator, and the like. Among these, a photocrosslinking initiator that can promote photopolymerization using ultraviolet rays is preferable because it does not need to be heated at a high temperature and is not damaged by heat.

  Examples of the photocrosslinking initiator, among them, those that undergo radical polymerization by cleavage, those that undergo radical polymerization by extracting hydrogen, or those that undergo cationic polymerization by generating ions can be given. And may be appropriately selected depending on the prepolymer and monomer to be used.

Examples of radical type photopolymerization initiators include benzoin ether, ketal, acetophenone, and thioxanthone.
In addition, examples of cationic photopolymerization initiators include diazonium salts, diaryliodonium salts, triarylsulfonium salts, triarylbirylium salts, benzylpyridinium thiocyanate, dialkylphenacylsulfonium salts, dialkylhydroxyphenylphosphonium salts and the like. it can.
These photopolymerization initiators may be used alone or in combination of two or more.

  The blending amount of the photopolymerization initiator is usually preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the acrylate compound, more preferably 1 part by mass or more and 5 parts by mass or less, and especially 2 parts by mass or more or 5 More preferably, it is at most part by mass.

(particle)
Particles may be used in the adhesive layer in order to improve slipperiness or blocking.
The average particle diameter of the particles is preferably in the range of 0.01 to 1.0 μm from the viewpoint of slipperiness or blocking improvement and film transparency, and more preferably 0.03 μm or more or 0.5 μm or less. A range of 0.05 μm or more or 0.2 μm or less is preferable.
Specific examples of the particles include silica, alumina, kaolin, calcium carbonate, and organic particles.

(Other ingredients)
The adhesive layer may contain an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an ultraviolet absorber, an antioxidant, a foaming agent, a dye, a pigment and the like as necessary. These additives may be used independently and may use 2 or more types together as needed.

  When providing an adhesive layer by off-line coating, dissolve or disperse the above-mentioned series of compounds in an organic solvent, and apply a coating solution adjusted to a solid content concentration of about 0.1 to 50% by mass on the polyester film. Preferably, the laminated film is produced in the same manner as described above. In addition, two or more kinds of organic solvents may be used in the coating liquid for the purpose of improving dispersibility, improving film forming property, and the like within the range not impairing the gist of the present invention.

(Hardness)
The adhesive layer preferably has a hardness of 1 × 10 ⁴ Pa or more and 1 × 10 ⁷ Pa or less as indicated by a storage elastic modulus (25 ° C.).
If the storage elastic modulus is 1 × 10 ⁷ Pa or less, it is preferable because an adequate adhesive strength that can be reworked can be secured initially. On the other hand, if the storage elastic modulus is 1 × 10 ⁴ Pa or more, the cohesive force of the adhesive layer is secured, and contamination due to adhesive residue can be reduced, which is preferable.
From this point of view, the storage elastic modulus of the adhesive layer is preferably 1 × 10 ⁴ Pa or more and 1 × 10 ⁷ Pa or less, and more preferably 2 × 10 ⁴ Pa or more or 7 × 10 ⁶ Pa or less, among them 3 × 10 6 More preferably, it is ⁴ Pa or more or 5 × 10 ⁶ Pa or less.
The storage elastic modulus which shows hardness here is a value of the shear storage elastic modulus in 25 degreeC calculated | required by the method described in the Example mentioned later.

(Surface roughness)
The surface roughness (S5p) of the pressure-sensitive adhesive layer surface of the laminated film is preferably 10 nm or more and 1,000 nm or less.
If the surface roughness of the adhesive layer surface is in the above range, the adherend can be prevented from being damaged by the strength of the stress generated when the film is peeled off.
From this point of view, the surface roughness (S5p) of the adhesive layer surface is preferably 10 nm or more and 1,000 nm or less, and more preferably 15 nm or more or 900 nm or less, and more preferably 20 nm or more or 700 nm or less.
Therefore, it can be effectively used as a laminated film for protecting the surface of a thin optical member such as a glass plate or a prism sheet having a moth-eye structure.

  In order to adjust the surface roughness (S5p) of the pressure-sensitive adhesive layer to the above range, for example, it is adjusted by adjusting the average particle diameter of the particles to be blended in the polyester film or by adjusting the thickness of the pressure-sensitive adhesive layer. Can do. However, it is not limited to these methods.

(Thickness)
The thickness of the adhesive layer (after drying) is preferably 100 nm or more and 9000 nm or less, more preferably 120 nm or more and 6,000 nm or less, and particularly preferably 150 nm or more or 2,000 nm or less.
When the thickness of the adhesive layer is in the above range, for example, when used as a protective film such as a thin glass plate or a prism sheet having a moth-eye structure, these adherends are broken against external stress. It is suitable for protecting the surface of a member that has a concern. Moreover, peeling of the protective film from these adherends is performed smoothly, and it is preferable at the point which can prevent a deformation | transformation and a failure | damage of an adherend.

The thickness of the adhesive layer (after drying) is preferably 0.1 to 1,000 with respect to the surface roughness (S5p) of the adhesive layer surface.
Since the thickness of the pressure-sensitive adhesive layer is extremely small and the surface of the pressure-sensitive adhesive layer is moderately rough, the ratio of the thickness of the pressure-sensitive adhesive layer to the surface roughness (S5p) of the surface of the pressure-sensitive adhesive layer is a feature of the present laminated film. Can be expressed effectively.
From this viewpoint, the thickness (after drying) of the pressure-sensitive adhesive layer is preferably 0.1 to 1,000 with respect to the surface roughness (S5p) of the pressure-sensitive adhesive layer surface. Among these, 0.3 or more or 350 or less, and more preferably 0.5 or more or 300 or less is more preferable.

Moreover, when the said polyester film contains particle | grains, the thickness (after drying) of an adhesion layer is 0.03 (150 / 5,000) or more and 200 (2,000) with respect to the average particle diameter of the particle | grains in a polyester film. / 10) or less.
As described above, since the roughness of the adhesive layer surface can be adjusted by blending the particles in the polyester film, the ratio of the thickness of the adhesive layer to the average particle diameter of the particles in the polyester film is The characteristics of the film can be effectively represented.
From this viewpoint, the thickness (after drying) of the pressure-sensitive adhesive layer is preferably 0.03 or more and 200 or less with respect to the average particle diameter of the particles in the polyester film. More preferably, it is 0.08 or more or 100 or less.

(Lamination method)
As a method for providing the adhesive layer, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, etc. can be employed.

  The drying and curing conditions for forming the adhesive layer on the polyester film are not particularly limited. For example, when an adhesive layer is provided by off-line coating, heat treatment is usually performed at 80 to 180 ° C. for 3 to 40 seconds, preferably 100 to 160 ° C. for 3 to 40 seconds.

  On the other hand, when an adhesive layer is provided by in-line coating, it is usually preferable to perform heat treatment at 70 to 280 ° C. for 3 to 200 seconds as a guide.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. The polyester film constituting the present laminated film may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

<Antistatic layer>
The antistatic layer described above can be provided mainly for providing antistatic performance and reducing adhesion of surrounding dust and the like due to peeling charging and frictional charging. However, the antistatic layer is not necessarily provided.

  The antistatic layer may be provided by in-line coating or may be provided by off-line coating. From the viewpoint of manufacturing cost and stabilization of antistatic performance by in-line heat treatment, in-line coating is preferably employed.

(Antistatic agent)
There is no restriction | limiting in particular as an antistatic agent contained in an antistatic layer, A conventionally well-known antistatic agent can be used. Among these, a polymer type antistatic agent is preferable because of its good heat resistance and moist heat resistance. Examples of the polymer type antistatic agent include a compound having an ammonium group, a polyether compound, a compound having a sulfonic acid group, a betaine compound, and a conductive polymer.

(Release agent)
The antistatic layer can contain a release agent for surface decontamination, reduction of blocking with the adhesive layer, improvement of scratch resistance, and the like.
As the release agent, conventionally known materials can be used, and examples thereof include a long-chain alkyl group-containing compound, a fluorine compound, a silicone compound, and a wax.

  The antistatic layer contains various polymers such as polyester resin, acrylic resin, and urethane resin, and a crosslinking agent that can be used to form an adhesive layer in order to improve coating appearance, transparency, and slipperiness. Is also possible. In particular, from the viewpoint of improving the durability of the antistatic layer, it is preferable to contain a crosslinking agent such as a melamine compound, an oxazoline compound, an isocyanate compound, or an epoxy compound, and among them, a melamine compound is particularly preferable.

  As long as the gist of the present invention is not impaired, it is also possible to use particles in combination with the formation of the antistatic layer in order to improve blocking properties or slip properties.

  Furthermore, the antistatic layer can contain an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an ultraviolet absorber, an antioxidant, a foaming agent, a dye, a pigment, etc., as necessary. It is.

  From the viewpoint of obtaining an antistatic effect, the content of the antistatic agent in the antistatic layer is preferably 0.5% by mass or more, more preferably 3% by mass or more and 90% by mass or less, of which 5% by mass. % Or more and 70% by mass or less, more preferably 8% by mass or more and 60% by mass or less.

  The proportion of the crosslinking agent in the antistatic layer is preferably 80% by mass or less, more preferably 5% by mass or more and 60% by mass or less, and more preferably 10% by mass or more or 50% by mass or less. preferable.

  Regarding the formation of the antistatic layer, the above-mentioned series of compounds is used as a solution or solvent dispersion, and a coating solution prepared by adjusting the solid content concentration to about 0.1 to 80% by mass as a guide is applied on the polyester film. It is preferable to produce a polyester film. In particular, an aqueous solution or aqueous dispersion is more preferable because the adhesive layer is provided by in-line coating in particular. The coating solution may contain a small amount of an organic solvent for the purpose of improving the dispersibility in water, the film forming property, and the like. Moreover, only one type of organic solvent may be used, and two or more types may be used as appropriate.

  The thickness of the antistatic layer (after drying) is preferably 0.001 to 1 μm, more preferably 0.01 μm or more and 0.5 μm or less, and particularly preferably 0.02 μm or more or 0.2 μm or less. . By using the film thickness of the antistatic layer in the above range, it becomes possible to improve the antistatic property and ensure a good coating appearance.

  As a method of forming the antistatic layer, for example, gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, impregnation coating, kiss coating Conventionally known coating methods such as spray coating, calender coating, and extrusion coating can be used.

  The drying and curing conditions for forming the antistatic layer are not particularly limited. Regarding drying of a solvent such as water used in the coating solution, it is preferably in the range of 70 to 150 ° C, more preferably 80 to 130 ° C, and still more preferably 90 to 120 ° C. The drying time is, as a standard, 3 to 200 seconds, preferably 5 to 120 seconds. Further, in order to improve the strength of the adhesive layer or the antistatic layer, it is preferably subjected to a heat treatment step in the range of 180 to 270 ° C., more preferably 200 to 250 ° C., and further preferably 210 to 240 ° C. in the film manufacturing process. It is. The time of the heat treatment step is, as a standard, in the range of 3 to 200 seconds, preferably 5 to 120 seconds.

  Moreover, you may use together heat processing and active energy ray irradiations, such as ultraviolet irradiation, as needed. The polyester film constituting the present laminated film may be subjected to surface treatment such as corona treatment and plasma treatment in advance.

The surface resistance value of the antistatic layer is preferably 1 × 10 ¹² Ω or less, preferably 1 × 10 ¹¹ Ω or less, and more preferably 5 × 10 ¹⁰ Ω or less. In the case of the above range, it is possible to make a film with little adhesion of dust and the like around it.

Physical Properties of the Laminated Film
(Peeling force)
The peel strength (Y1) of the adhesive layer of the present laminated film is preferably 10 mN / cm or more, more preferably 20 mN / cm or more or 600 mN / cm or less, among them 40 mN / cm or more It is particularly preferably 300 mN / cm or less, more preferably 40 mN / cm or more, or 100 mN / cm or less.
If the peeling force (Y1) of the pressure-sensitive adhesive layer of the present laminated film is in the above range, for example, the present laminated film can be protected from surface contamination or damage of the adherend without lifting from the adherend during processing and transportation. So preferred.
In addition, the peeling force (Y1) of the adhesive layer of this laminated film is a 180 ° peeling force measured at a tensile speed of 0.3 m / min according to JIS K 6854-2.
The peeling force (Y1) of the adhesive layer of the present laminated film can be adjusted by adjusting the surface roughness (S5p) of the surface of the adhesive layer, the hardness of the adhesive layer, and the viscosity behavior of the adhesive layer.

The peel strength (Y2) of the adhesive layer of the present laminated film is preferably 5 mN / cm or more, more preferably 10 mN / cm or more or 500 mN / cm or less, and more preferably 20 mN / cm or more. It is particularly preferably 300 mN / cm or less, more preferably 20 mN / cm or more, or 100 mN / cm or less.
If the peeling force (Y2) of the pressure-sensitive adhesive layer of the present laminated film is in the above-mentioned range, the present laminated film smoothly peels from the adherend, for example, even when peeling at high speed with a peeling device. It is preferable because deformation and damage of the body can be prevented.
In addition, the peeling force (Y2) of the adhesion layer of this laminated film is a 180 ° peeling force measured at a tensile speed of 30 m / min according to JIS K 6854-2.
The peeling force (Y2) of the adhesive layer of this laminated film can be adjusted by adjusting the surface roughness of the adhesive layer surface, the hardness of the adhesive layer, and the viscous behavior of the adhesive layer.

(Viscous behavior of adhesive layer; log decay rate)
The logarithmic attenuation factor at 30 ° C. measured by a rigid pendulum physical property tester on the surface of the adhesive layer of the present laminated film is preferably in the range of 0.01 or more and 0.1 or less, and more preferably 0.02 or more or 0.1 or less. It is more preferable that the ratio is 08 or less, and more preferably 0.03 or more or 0.05 or less.
The logarithmic decay rate described above represents a viscous behavior when shearing is applied to the pressure-sensitive adhesive layer. A larger value indicates that the viscosity of the pressure-sensitive adhesive layer is larger. Therefore, if the logarithmic attenuation factor is within the above range, the viscosity of the adhesive layer is adjusted appropriately, for example, rework is possible at the initial stage, and the laminated film does not rise from the adherend during processing and transportation. This is preferable because a sufficient adhesive force is secured. Further, for example, even when peeling is performed at high speed by a peeling apparatus, the present laminated film is smoothly peeled from the adherend, and deformation and damage of the adherend can be prevented, which is preferable.
The logarithmic attenuation factor on the surface of the pressure-sensitive adhesive layer of the present laminated film can be adjusted to the above range by adjusting the thickness and hardness of the pressure-sensitive adhesive layer.

  As described above, the laminated film satisfies the above range of logarithmic decay rates, and thus it is firmly attached to the adherend when it is not necessary to peel off, for example, in the product conveying step during the manufacturing process. On the other hand, when the surface protective film is automatically peeled from the product using the peeling device, it can be smoothly peeled off. Furthermore, it is used for surface protection of adherends that may be damaged depending on the strength of stress generated when the surface protective film is peeled off, for example, thin film optical members such as thin glass plates and prism sheets having a moth-eye structure. Even in the case, it is possible to provide a laminate film which can be peeled off smoothly.

(Logarithmic decay ratio)
The logarithmic attenuation factor is in the above range, and the logarithmic attenuation factor ratio at 30 ° C. in the range of 0.10 or more and 1.40 or less, similarly measured on the adhesive layer surface of the present laminated film, using a rigid pendulum physical property tester It is preferable that the ratio be in the range of 0.30 or more or 1.00 or less, and more preferably in the range of 0.40 or more or 0.80 or less.
The above-mentioned logarithmic damping ratio represents the change in viscosity behavior when the adhesive layer continues to be sheared, and indicates that the smaller the numerical value is, the harder the adhesive layer becomes with shear. Therefore, if the logarithmic attenuation ratio is within the above range, the laminated film can be peeled off from the adherend more smoothly, for example, even when peeled at a high speed by a peeling device. It is preferable because it can prevent body deformation and damage.
The logarithmic attenuation factor ratio on the surface of the pressure-sensitive adhesive layer of the present laminated film can be adjusted to the above range by adjusting the thickness and hardness of the pressure-sensitive adhesive layer. However, it is not limited to these means.

<Explanation of the phrase>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X is preferably greater than X” or “preferably Y”. It also includes the meaning of “smaller”.
Also, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), “greater than X is preferable” or “preferably less than Y” It also includes the intention.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples.
The measurement method and evaluation method used in the present invention are as follows.

(1) Intrinsic viscosity of polyester (dl / g)
1 g of the polyester from which other polymer components and pigments incompatible with the polyester were removed was precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) was added and dissolved, and measurement was performed at 30 ° C.

(2) Average particle size (d50: μm)
The value of 50% integration (mass basis) in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring device (“SA-CP3 type” manufactured by Shimadzu Corporation) was defined as the average particle size.

(3) Surface roughness (S5p)
Observation measurement, analysis and analysis of adhesive layer surface and polyester film surface of laminated films (samples) obtained in Examples and Comparative Examples are performed using the following measuring device, and surface roughness (S5p; '' Asked. Moreover, observation measurement was performed about arbitrary three places of the adhesion layer surface, and the average value of the n = 3 was made into surface roughness (S5 p).

* Equipment: Non-contact surface shape measurement system Bart Scan 2.0
R5300H type (manufactured by Ryoka System)
* Observation measurement conditions CCD camera for measurement: 1/3 inch Objective lens: x 10
Observation area: 469 × 351 μm ² ,
View size: 640 x 480 pixels
Measurement mode: wave mode Measurement wavelength: 530 nm
Scan range: ± 5μm

* Analysis conditions Software used: VS-Viewer (latest version)
Interpolation condition: Complete interpolation Surface correction condition: Fourth-order polynomial approximation

(4) Weight average molecular weight (Mw), number average molecular weight (Mn)
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured using GPC (HLC-8320GPC manufactured by Tosoh Corporation). Under the present circumstances, each average molecular weight was computed by polystyrene conversion.

(5) Pressure-Sensitive Adhesive Layer, Coating Film Thickness of Antistatic Layer The surface of the pressure-sensitive adhesive layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the sections prepared by the ultrathin section method were stained with RuO ₄ , and the cross section of the adhesive layer was measured using a TEM.
However, when the coating film thickness of the adhesive layer is about 3,000 nm or more, the cross section of the adhesive layer was measured using SEM. In that case, the surface of the adhesive layer was vapor-deposited with platinum / palladium, embedded in an epoxy resin, and then the cross-section of the adhesive layer adjusted for observation was used for measurement.
In addition, the film thickness was measured in the location which does not contain the part of particle | grains.

(6) Storage elastic modulus of adhesive layer (25 ° C)
About each adhesive which forms the adhesion layer of the laminated | multilayer film (sample) obtained by the Example and the comparative example, a dynamic viscoelasticity measurement is performed according to JISK7244-10 using the following apparatus, Shear at 25 degreeC The storage modulus was read as the storage modulus of each adhesive layer.
Measuring device: MARSII (made by Thermo Fisher Scientific)
Measurement method: Shear method Measurement jig: φ 20 parallel plate Distortion: 0.1%
Temperature range: -50 ° C to 200 ° C
Heating rate: 3 ° C / min
Frequency: 1 Hz

In addition, the sheet | seat of about 0.2 mm thickness was formed with each adhesive, and this was piled up and crimped | bonded to form a sheet of about 1.6 mm thickness for the measurement sample.
Moreover, the drying conditions at the time of forming a sheet about 0.2 mm in thickness with each adhesive, and UV curing conditions were as shown in Table 4 or 5 below.
Further, the sheet was pressure-bonded by reciprocating five times with a 1.5 kg rubber roller (manual pressure bonding apparatus).

(7) Viscosity behavior of adhesive layer (logarithmic damping factor)
Using the following measuring device, the logarithmic attenuation factor and the logarithmic attenuation factor ratio on the adhesive layer surface of the laminated films (samples) obtained in Examples and Comparative Examples were determined.
Here, the “logarithmic decay rate” was defined as an average value from 7 to 9 minutes from the start of measurement.
Further, the logarithmic attenuation factor ratio was determined by the following formula (III).
Log attenuation ratio = (average value from 7 to 9 minutes from the start of measurement) / (average value from 0 to 20 seconds from the start of measurement) · · · (III)

In addition, it measured twice about the laminated | multilayer film (sample) obtained by the Example and the comparative example, and made the average value of n = 2 the logarithmic decay rate and logarithmic decay rate ratio of the adhesive layer.
The logarithmic damping factor represents the ratio of the elastic element to the viscous element, and the smaller the value, the harder the adhesive layer is.
In addition, the smaller the numerical value of the logarithmic attenuation factor ratio, the more the property of the adhesive layer becomes harder with shearing.

* Equipment: Rigid pendulum type physical property tester RPT-3000W (manufactured by A & D)
* Measurement conditions Measurement pendulum: FRB-200
Edge for measurement: RBP-040
Measurement temperature: 30 ° C
Measurement time: 10 minutes Measurement interval (data acquisition interval): 10 seconds

(Criteria)
○: The logarithmic attenuation factor at 30 ° C. is 0.01 or more and 0.10 or less.
X: The logarithmic attenuation factor at 30 ° C. is less than 0.01 or more than 0.10.

(8) Peeling force (Y1, Y2) evaluation Adhesion of laminated films (samples) obtained in Examples and Comparative Examples of 5 cm width on the surface of an acrylic plate (Kuraray Co., Ltd. “Comoglass”) having a thickness of 1 mm as an adherend The layer surface was subjected to two reciprocating pressure bonding with a 2 kg rubber roller (manual pressure bonding device) having a width of 5 cm, and the peeling force after being left at room temperature for 1 hour was measured.
For the peeling force (Y1), a high-speed peeling tester manufactured by Tester Sangyo was used, and 180 ° peeling was performed in accordance with JIS K 6854-2 under the condition of a tensile speed of 0.3 m / min.
For the peeling force (Y2), a high-speed peeling tester manufactured by Tester Sangyo was used, and 180 ° peeling was performed in accordance with JIS K 6854-2 under the condition of a tensile speed of 30 m / min.

(9) Surface Resistance of Antistatic Layer Surface The surface resistance (Ω) of the antistatic layer was measured according to the following method (9-1). In the method (9-1), since the surface resistivity lower than 1 × 10 ⁸ Ω cannot be measured sufficiently, the method (9-2) was used for the sample that could not be measured in (9-1).

(9-1) A high resistance measuring device manufactured by Nippon Hewlett Packard Co., Ltd .: HP 4339 B and measuring electrode: HP 16008 B, after sufficiently conditioning the polyester film under a measuring atmosphere of 23 ° C., 50% RH, with an applied voltage of 100 V The surface resistance (Ω) of the antistatic layer after one minute was measured.

(9-2) Low resistance meter manufactured by Mitsubishi Chemical Co., Ltd .: Using a Loresta GP MCP-T600, conditioning the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH, and then the surface resistance (Ω) of the antistatic layer Was measured.

(10) Peelability evaluation (practical property substitution evaluation)
Adhesive layer surface of laminated film (sample) obtained by Example and comparative example of 5 cm width strip-like on the surface of alkali-free glass (AZ ONE "EAGLEX G"; 100 x 100 mm size) with a thickness of 0.7 mm as an adherend Were attached, and the amount of warping deformation of the adherend was measured when the laminated film was peeled off by hand, and the peeling condition was observed when peeled.
At this time, the bonding was performed by aligning the adhesive layer surface of each laminated film with the glass surface, and then reciprocally pressing a 2 kg rubber roller (manual pressure bonding device) having a width of 5 cm from the top.
Further, the amount of warpage deformation of the adherend is determined when the part of 10 mm width is fixed to the surface plate and the laminated film starts to be peeled off from the side facing the side of the adherend placed on the surface plate. The height of the side opposite to the fixed side measured from the surface plate was measured.

The peeling condition at the time of peeling was judged by the following judgment criteria. Here, Δ or more is a practical level or more.
(Criteria)
○: Even if peeled off vigorously, there was no feeling of peeling resistance, and peeling was possible smoothly.
:: When peeled off vigorously, a feeling of peeling resistance at peeling was felt.
The amount of warpage deformation was 2 mm or less, and there was no fear of breakage of the adherend.
X: It was heavy and difficult to feel peeling resistance at peeling when peeling vigorously.
In addition, when the amount of warpage deformation is 5 mm or more, there is a possibility that the adherend may be damaged, and when peeling off, zipping may occur.

(11) Comprehensive evaluation About each laminated film obtained by the Example and the comparative example, it determined by the following criteria.
(Criteria)
:: All items are 粘性 regarding the viscosity behavior, antistatic property and releasability of the adhesive layer.
(Triangle | delta): At least one is (triangle | delta) about each item of the viscous behavior of an adhesion layer, antistatic property, and peelability. X: Viscous behavior of the adhesive layer, antistatic property. For each item of peelability, at least one is x.

<Various materials>
Various materials used in Examples and Comparative Examples are prepared as follows.

(Method for producing polyester (A))
100 parts by mass of dimethyl terephthalate, 60 parts by mass of ethylene glycol, 30 ppm of ethyl acid phosphate with respect to the produced polyester, and 100 mg of magnesium acetate tetrahydrate with respect to the produced polyester as a catalyst at 260 ° C. in a nitrogen atmosphere at 260 ° C. Reaction. Subsequently, 50 ppm of tetrabutyl titanate is added to the formed polyester, the temperature is raised to 280 ° C. over 2 hours and 30 minutes, the pressure is reduced to 0.3 kPa absolute pressure, and melt polycondensation is carried out for another 80 minutes. A polyester (A) having 0.63 dl / g and a diethylene glycol amount of 2 mol% was obtained.

(Production method of polyester (B))
100 parts by mass of dimethyl terephthalate, 60 parts by mass of ethylene glycol, and magnesium acetate tetrahydrate as a catalyst. 900 ppm of the produced polyester was subjected to esterification reaction at 225 ° C. in a nitrogen atmosphere. Subsequently, 3500 ppm of orthophosphoric acid and 70 ppm of germanium dioxide to the formed polyester are added, the temperature is raised to 280 ° C. over 2 hours and 30 minutes, and the pressure is reduced to the absolute pressure of 0.4 kPa, It was melt polycondensed for 85 minutes to obtain a polyester (B) having an intrinsic viscosity of 0.64 dl / g and a diethylene glycol amount of 2 mol%.

(Production method of polyester (C))
In the method for producing polyester (A), polyester was used in the same manner as the method for producing polyester (A) except that 0.3 parts by mass of spherical silica particles having an average particle size of 2.7 μm were added before melt polymerization. I got (C).

(Production method of polyester (D))
In the method for producing polyester (A), polyester was used in the same manner as the method for producing polyester (A) except that 0.6 parts by mass of spherical silica particles having an average particle diameter of 3.2 μm were added before melt polymerization. I got (D).

(Composition constituting antistatic layer: coating solution 1)
The raw materials of the composition which comprises an antistatic layer are as follows, and the mixing | blending of the coating liquid 1 for forming an antistatic layer was shown in the following Table 1.

・ Polyester resin (B1)
Aqueous dispersion of polyester resin having the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4-butanediol / diethylene glycol = 56 / 40/4 // 70/20/10 (mol%)

Melamine compound (C1): hexamethoxymethylolmelamine particles (D1): spherical particles having a mean particle size of 0.07 μm

· Antistatic agent (E1) (compound having an ammonium group)
A polymer compound having a number average molecular weight of 50000, wherein the counter ion is a methanesulfonic acid ion, comprising a structural unit of the following formula (2).

(Method of producing adhesive layer composition (A))
Acrylate ester copolymer (vinyl acetate (vinyl acetate): 2-ethylhexyl acrylate (2EHA) = 25 mass%: 75 mass%, Mw = 6.2 × 10 ⁵ , Mn = 2.0 × 10 ⁵ ) 100 mass The adhesive layer composition (A) was prepared by adjusting the parts and 3233 parts by mass of toluene to a solid content concentration of 3% by mass.

(Method of producing adhesive layer composition (B))
Acrylic acid ester copolymer (vinyl acetate (vinyl acetate): 2-ethylhexyl acrylate (2EHA) = 25 mass%: 75 mass%, Mw = 6.2 x 10 ⁵ , Mn = 2.0 x 10 ⁵ ) 100 mass Parts, 5 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF, trade name "Irgacure 184") as a photopolymerization initiator, and 420 parts by mass to 3233 parts by mass of toluene, solid content concentration 3 to 20 parts It adjusted to% and produced the adhesion layer composition (B).

(Method of producing adhesive layer composition (C))
Acrylic ester triblock copolymer (methyl (meth) acrylate (MMA): n-butyl acrylate (BA) = 40% by mass: 60% by mass, Mw = 5.2 × 10 ⁴ , Mn = 4.8 × 10 ⁴ ) An adhesive layer composition (C) was prepared by adjusting 100 parts by mass, 1940 parts by mass of ethyl acetate and 1293 parts by mass of toluene to a solid content concentration of 3% by mass.

(Method of producing adhesive layer composition (D))
Acrylic ester triblock copolymer (methyl (meth) acrylate (MMA): n-butyl acrylate (BA) = 40% by mass: 60% by mass, Mw = 5.2 × 10 ⁴ , Mn = 4.8 × 10 ⁴ ) 100 parts by mass, 0.5 part by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF, trade name “Irgacure184”) as a photopolymerization initiator and 3233 parts by mass of ethyl acetate were mixed at a solid concentration of 3 It adjusted to mass% and produced the adhesion layer composition (D).

(Method of producing adhesive layer composition (E))
Acrylic acid ester copolymer (2-ethylhexyl acrylate (2EHA): 4-hydroxybutyl acrylate (4 hydroxy BA) = 95% by mass: 5% by mass, Mw = 1.2 x 10 ⁶ , Mn = 5.4 x 10 ⁵ ) 100 parts by weight, 4 parts of polyisocyanate and 3233 parts by weight of ethyl acetate were adjusted to a solid content concentration of 3% by weight to prepare an adhesive layer composition (E).

Example 1
Polyesters (A), (B), and (C) were mixed at a ratio of 80 parts by weight, 3 parts by weight, and 17 parts by weight, respectively, and a raw material for the substrate outermost layer (surface layer) was used. B) Each mixed raw material mixed with 97 parts by mass and 3 parts by mass as a raw material for the intermediate layer of the base material is supplied to two extruders, each melted at 285 ° C., and then set to 40 ° C. On the cooled roll, it was coextruded in a layer configuration of 2 types and 3 layers (surface layer / intermediate layer / surface layer = 3: 19: 3 discharge amount) and cooled and solidified to obtain an unstretched sheet.
Then, after stretching at a film temperature of 85 ° C. in the machine direction by 3.2 times to make a longitudinally stretched film using a roll peripheral speed difference, the coating solution 1 shown in Table 1 is coated on one side of this longitudinally stretched film. It is applied to a thickness (after drying) of 0.06 μm (antistatic layer), introduced to a tenter, dried at 95 ° C. for 10 seconds, and then stretched 4.3 times at 120 ° C. in a transverse direction, 230 ° C. After a heat treatment for 10 seconds, a polyester film (base material) having a thickness of 25 μm and a film (base material) surface roughness (S5p) of 51 nm was obtained.

  Using the bar coater shown in Table 2, the pressure-sensitive adhesive layer composition (A) was applied to one side of the obtained polyester film opposite to the antistatic layer so that the thickness (after drying) was 150 nm. After heat treatment at 1 ° C. for 1 minute, a laminated film (sample) consisting of an antistatic layer / polyester film (base material) / adhesive layer was obtained. The laminated film (sample) is not laminated with the release film.

Example 2
In Example 1, using a pressure-sensitive adhesive layer composition (B) instead of the above-mentioned pressure-sensitive adhesive layer composition (A), a thickness (after drying) of 170 nm was applied and heat treated at 100 ° C. for 1 minute; Furthermore, a laminated film (sample) was obtained in the same manner as in Example 1 except that irradiation treatment was performed with a high-pressure mercury lamp UV light so that the integrated light amount was 200 mJ / cm ² in a nitrogen-substituted atmosphere.

<Example 3 to Example 8>
In Example 1, the composition of the substrate outermost layer, the substrate intermediate layer and the adhesive layer, and the production conditions (the thickness of the adhesive layer depending on the type of bar coater and the presence or absence of UV curing) were changed as shown in Table 2 or 3. It manufactured similarly to Example 1 or 2 except having obtained laminated | multilayer film (sample).
In addition, the adhesive layer thickness was changed by changing the bar coater to be used.

Comparative Examples 1 to 3
A laminated film (sample) was produced in the same manner as in Example 2 except that the thickness of the adhesive layer was changed as shown in Table 3 using the bar coater shown in Table 2 in Example 2.

  The characteristics of the respective laminated films (samples) obtained in the above Examples and Comparative Examples are shown in Tables 4 to 5 below.

  From the results of the above examples and various tests conducted by the inventors so far, regarding the laminated film in which the adhesive layer is laminated on one side of the polyester film, the thickness of the adhesive layer is 100 nm or more and 9000 nm or less, and the surface of the adhesive layer If the surface roughness (S5p) is 10 nm or more and 1,000 nm or less and the logarithmic decay rate (30 ° C.) on the surface of the adhesive layer is 0.01 or more and 0.10 or less, it can be done at once with a peeling device or the like. When peeling or unwinding from the wound state, when necessary, it can be peeled smoothly without damage, but when peeling force is applied at low speed, such as when transporting products. It turned out that it can adhere, without peeling from a to-be-adhered body.

From the results of the above examples and various tests conducted by the inventors so far, the synergistic effect of the hardness of the particles on the polyester film surface, which is the foundation when providing the adhesive layer, and the hardness of the adhesive layer, It can be considered that an effect can be obtained. However, if the thickness of the pressure-sensitive adhesive layer is too large, it can be considered that the hardness of the particles is absorbed by the thickness of the pressure-sensitive adhesive layer, and the influence is reduced. In view of these points and the results of various tests conducted by the inventor and the above embodiment, if the thickness of the adhesive layer is 100 nm or more and 9000 nm or less, the same effect as that of the above embodiment can be obtained. If you can, you can think.
Moreover, in the said Example and comparative example, although d50 is used as an average particle diameter of particle | grains, as mentioned above, the diameter of several particle | grains was measured by SEM observation from the test result so far, and the average value was calculated | required. The same applies to use.

  According to the laminated film of the present invention, for the surface protection of various adherends, for example, it is firmly bonded in the product transport process during the manufacturing process that does not need to be peeled, while using a peeling device, When the surface protective film is automatically peeled off from the product, it is peeled off smoothly, and by satisfying both of the properties that have been difficult to achieve at the same time, it has good adhesive properties. In addition, in the surface protection of an adherend that may be damaged depending on the strength of the stress generated when the surface protective film is peeled off, for example, a thin film optical member (thin glass plate, prism sheet having a moth-eye structure, etc.) It is possible to provide a laminate film that can be peeled off smoothly. Furthermore, as its application development, it is also suitable for protecting the surface of various adherends such as glass, metal and resin plate, and its industrial value is high.

Claims (3)

  It is a laminated film in which an adhesive layer is laminated on one side of a polyester film, the thickness of the adhesive layer is 100 nm or more and 9000 nm or less, and the surface roughness (S5p) of the adhesive layer surface is 10 nm or more and 1,000 nm or less, A laminated film characterized in that a logarithmic decay rate at 30 ° C. measured by a rigid pendulum type physical property tester on the adhesive layer surface is in a range of 0.01 or more and 0.10 or less.   The laminated film according to claim 1, further comprising an antistatic layer laminated on one side of the polyester film opposite to the side on which the adhesive layer is laminated.   The laminated film according to claim 1 or 2, characterized in that the release film is not laminated.