JP2024008150A - resin film - Google Patents

Abstract

[Problem] To provide a resin film that is unlikely to peel off from an adherend even when it is attached to an adherend via a pressure-sensitive adhesive layer or adhesive layer and exposed to a high-temperature and high-humidity environment. [Solution] Resin film 1 is a resin film used with a pressure-sensitive adhesive layer or adhesive layer laminated on at least one side, and has a ratio of 0.3 to 2.5 between the contraction rate when heated at 120°C for 5 minutes and the expansion rate when stored in an environment at 85°C and 85% RH for 30 minutes. [Selected Figure] Figure 1

Description

The present invention relates to a resin film.

As a material for bonding members together, a pressure-sensitive adhesive sheet or an adhesive sheet, which has a resin film as a base material and has a pressure-sensitive adhesive layer or an adhesive layer laminated on both sides of the base material, is widely used (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2002-303730

However, when conventional pressure-sensitive adhesive sheets and adhesive sheets are bonded to an adherend and exposed to a high temperature and high humidity environment, peeling occurs between the sheet and the adherend. There was a case.

Therefore, an object of the present invention is to provide a bond between the adherend and the adherend even when the adherend is bonded to the adherend through an adhesive layer or an adhesive layer and exposed to a high temperature and high humidity environment. It is an object of the present invention to provide a resin film that does not easily peel off.

In order to solve the above problems, the present inventors have made extensive efforts and found that the ratio of the shrinkage rate during heating to the expansion rate under high temperature and high humidity environments is within a specific range as a base material for pressure-sensitive adhesive sheets and adhesive sheets. By using a resin film inside, the adhesive sheet or adhesive is resistant to peeling from the adherend, even when exposed to high temperature and high humidity environments while attached to the adherend. It has been found that a sheet can be obtained. The present invention was completed based on these findings.

The present invention is a resin film used with a pressure-sensitive adhesive layer or an adhesive layer laminated on at least one surface, and the shrinkage rate when heated at 120°C for 5 minutes and the temperature of 85°C and humidity of 85% RH. Provided is a resin film having a ratio of expansion ratio [former/latter] of 0.3 to 2.5 when stored for 30 minutes in an environment of

The resin film is preferably obtained by heat-treating a raw material film while applying tensile stress in at least one direction.

The resin film preferably contains as a main component one or more resins selected from polycarbonate resins, polyester resins, acrylic resins, cellulose resins, and cycloolefin resins.

The resin film is preferably used by laminating an adhesive layer on one side and laminating another resin film on the other side via the adhesive layer or an adhesive layer.

The resin film has a ratio [former/latter] of the expansion rate and the contraction rate when the other resin film is stored for 30 minutes at a temperature of 85° C. and a humidity of 85% RH from 1.0 to 3. Preferably, it is 0.

Even when the resin film of the present invention is bonded to an adherend through an adhesive layer or an adhesive layer and exposed to a high temperature and high humidity environment, it does not peel off from the adherend. is less likely to occur. For this reason, for example, by using the resin film of the present invention as a base material for a pressure-sensitive adhesive sheet or adhesive sheet, when the pressure-sensitive adhesive sheet or adhesive sheet is bonded to an adherend and exposed to a high temperature and high humidity environment, Also, peeling is less likely to occur between the adhesive sheet or adhesive sheet and the adherend.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an embodiment of a pressure-sensitive adhesive sheet and the like comprising a resin film of the present invention. It is a sectional view showing other embodiments, such as an adhesive sheet provided with the resin film of this invention. 1 is a cross-sectional view showing one embodiment of a method for manufacturing a resin film of the present invention. FIG. 1 is a cross-sectional view showing one form of use of a pressure-sensitive adhesive sheet, etc., including the resin film of the present invention.

[Resin film]
The resin film of the present invention is a resin film that is used with a pressure-sensitive adhesive layer or an adhesive layer laminated (directly laminated) on at least one surface. The resin film is preferably used with an adhesive layer laminated (directly laminated) on at least one surface. The above resin film is used, for example, as a base material or adherend for a pressure-sensitive adhesive sheet or an adhesive sheet. Note that the resin film is different from the release liner and its base material, which are peeled off when the pressure-sensitive adhesive layer or the adhesive layer is bonded to an adherend and used.

FIGS. 1 and 2 show an embodiment in which the resin film of the present invention is applied as a base material of a pressure-sensitive adhesive sheet. The adhesive sheet 10 shown in FIG. 1 is a single-sided adhesive sheet comprising the resin film 1 of the present invention and an adhesive layer 21 laminated on one side of the resin film 1. The adhesive surface of the adhesive layer 21 is protected by a release liner 31.

The adhesive sheet 10 shown in FIG. 2 includes a resin film 1 of the present invention, an adhesive layer 21 laminated on one side of the resin film 1, and an adhesive layer 22 laminated on the other side of the resin film 1. It is a double-sided adhesive sheet. The adhesive surface of the adhesive layer 21 is protected by a release liner 31, and the adhesive surface of the adhesive layer 22 is protected by a release liner 32.

The resin film has a shrinkage rate when heated for 5 minutes at a temperature of 120°C and an expansion rate when stored for 30 minutes in an environment of a temperature of 85°C and a humidity of 85% RH [former/latter] of 0.3. ~2.5. Note that in this specification, the shrinkage rate when heated at the above temperature of 120° C. for 5 minutes may be referred to as "heat shrinkage rate." Further, the expansion coefficient when stored for 30 minutes in an environment with a temperature of 85° C. and a humidity of 85% RH is sometimes referred to as a "high-humidity expansion coefficient."

The above ratio [heat shrinkage rate/high humidity expansion rate] is 0.3 or more, preferably 0.4 or more, more preferably 0.5 or more, still more preferably 0.6 or more, particularly preferably 0.7. That's all. Further, the above ratio is 2.5 or less, preferably 2.4 or less, more preferably 2.3 or less, still more preferably 2.2 or less, particularly preferably 2.1 or less. When the above ratio is within the above range, the heat shrinkage rate and high humidity expansion rate of the resin film are well balanced, and the resin film can be exposed to high temperature and high humidity when bonded to an adherend via an adhesive layer or an adhesive layer. When exposed to the environment, the expansion and contraction of the resin film are offset, and as a result, size changes are less likely to occur and peeling from the adherend is less likely to occur.

The ratio [heat shrinkage rate/high-humidity expansion rate] is calculated by employing the maximum value of each of the heat-shrinkage rate and the high-humidity expansion rate. For example, if the heat shrinkage rate of the resin film is the highest in the machine (MD) direction, and the resin film's high humidity expansion coefficient is the highest in the width (TD) direction, then the heat shrinkage rate is is the value in the MD direction, and the high-humidity expansion coefficient is the value in the TD direction. The heat shrinkage rate and the high-humidity expansion rate are preferably values in a direction selected from the MD direction and the TD direction, respectively.

In this specification, the heat shrinkage rate When the distance between the scores at normal temperature is a, and the distance between the scores after heating at 120° C. for 5 minutes is a′, it is calculated by the following formula (1).
X[%]=(a-a')/a×100 (1)

In this specification, the high-humidity expansion coefficient Y is a positive value, and on each of two opposing sides of a rectangular or square resin film, positions at arbitrary distances from the midpoint toward the center are evaluated as two points, and the heating Calculated by the following formula (2), where the distance between the above ratings before (at normal temperature) is a, and the distance between the above ratings after being stored for 30 minutes in an environment of temperature 85 ° C and humidity 85% RH is a'. be done.
Y[%]=(a'-a)/a×100 (2)

A resin film having the above ratio [heat shrinkage rate/high humidity expansion rate] within the above range can be produced by the method for producing a resin film described below. That is, the resin film is preferably a film obtained by heat-treating a raw material film while applying tensile stress in at least one direction. It should be noted that there are circumstances in which it is impossible or impractical to directly specify such a resin film by its structure or characteristics other than by expressing it in the manufacturing process.

The resin film contains resin as a main component. The resin film is formed from a composition containing resin as a main component. Examples of the above-mentioned resin films include various optical films such as plastic films, anti-reflection (AR) films, anti-glare (AG) films, polarizing plates, and retardation plates, porous materials such as cloth and nonwoven fabrics, nets, and foam sheets. can be mentioned. Further, it may be a porous film or a non-porous film.

As the above-mentioned resin, known or conventional film-forming resins can be used, such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerized polypropylene, block Copolymerized polypropylene, homopolyprolene, polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-vinyl acetate copolymer Polyolefin resins such as polymer (EVA), ethylene-propylene copolymer, cycloolefin resin, ethylene-butene copolymer, and ethylene-hexene copolymer; polyurethane; polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene Polyester resins such as terephthalate (PBT); polycarbonate resins; polyimide resins; polyetheretherketone; polyetherimide; polyamides such as aramid and wholly aromatic polyamide; polyphenylsulfide; fluororesin; polyvinyl chloride; polychloride Examples include vinylidene; cellulose resins such as triacetyl cellulose (TAC); silicone resins; acrylic resins such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate. Among these, polycarbonate resins, polyester resins, acrylic resins, cellulose resins, and polyolefin resins (especially cycloolefin resins) are preferred. Note that these resins may be used alone or in combination of two or more.

The content ratio of the resin in the resin film is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, based on the total amount (100% by mass) of the resin film, It may be 80% by mass or more, 90% by mass or more, or 95% by mass or more. Further, the resin film may contain components other than resin.

The resin film preferably has a saturated water absorption rate of 2.0% or less, more preferably less than 1.5%, even more preferably less than 1.1%, still more preferably 1.0% or less, particularly preferably It is 0.8% or less. If the above-mentioned saturated water absorption rate is 2.0% or less, when exposed to a high temperature and high humidity environment while bonded to an adherend through an adhesive layer or an adhesive layer, Peeling is even less likely to occur between the layers. The above saturated water absorption rate can be determined in accordance with JIS K7209.

The thickness of the resin film is not particularly limited, but is preferably, for example, 10 to 1000 μm, more preferably 50 to 800 μm, and still more preferably 70 to 500 μm.

At least one surface of the resin film may be subjected to, for example, corona discharge treatment, plasma treatment, sand mat treatment, ozone exposure treatment, flame exposure treatment, etc., for the purpose of improving adhesion and retention with the pressure-sensitive adhesive layer or adhesive layer. Physical treatment such as treatment, high-voltage electric shock exposure treatment, and ionizing radiation treatment; chemical treatment such as chromic acid treatment; and surface treatment such as adhesion treatment using a coating agent (undercoat). The surface treatment for improving adhesion is preferably applied to the entire surface of the resin film on the side on which the pressure-sensitive adhesive layer or the adhesive layer is laminated.

It is preferable that the resin film is used by laminating another resin film via a pressure-sensitive adhesive layer or an adhesive layer.

The ratio [former/latter] between the high-humidity expansion coefficient of the resin film and the shrinkage ratio of the other resin film when stored for 30 minutes in an environment with a temperature of 85°C and a humidity of 85% RH is 0.5 or more. is preferable, more preferably 0.9 or more, still more preferably 1.0 or more. Further, the above ratio is preferably 3.5 or less, more preferably 3.0 or less, still more preferably 2.0 or less. The shrinkage rate of the other resin film when stored for 30 minutes in an environment with a humidity of 85% RH is sometimes referred to as a "high-humidity shrinkage rate." When the ratio is within the above range, the expansion and contraction of the resin film can be balanced when stored for 30 minutes in an environment with a humidity of 85% RH, so the resin film, the adhesive layer, or the adhesive layer, Peeling is less likely to occur between the layers of the other resin films.

The high-humidity shrinkage rate is not particularly limited, but is preferably 1.0% or less (for example, 0 to 1.0%), more preferably 0.5% or less, even more preferably 0.2% or less. In the present specification, the high-humidity shrinkage rate Z is calculated using two scores at arbitrary distances from the midpoint toward the center on each of the two opposing sides of the other resin film, which is rectangular or square, before heating ( Calculated using the following formula (3), where b is the distance between the scores at room temperature), and b' is the distance between the scores after being stored for 30 minutes in an environment with a temperature of 85°C and humidity of 85% RH. . Note that the maximum value of the high-humidity shrinkage rate is adopted. The high-humidity shrinkage rate is preferably a value in a direction selected from the MD direction and the TD direction.
Z [%] = (bb')/b x 100 (3)

The other resin films mentioned above contain resin as a main component. The other resin films mentioned above are formed from a composition containing resin as a main component. Other resin films mentioned above include various optical films such as plastic films, antireflection (AR) films, antiglare (AG) films, polarizing plates, and retardation plates, porous materials such as cloth and nonwoven fabrics, nets, and foamed materials. Examples include sheets. Further, it may be a porous film or a non-porous film.

As the above-mentioned resin, known or conventional film-forming resins can be used, and examples thereof include those exemplified and explained as resins constituting the resin film of the present invention. The content ratio of the resin in the other resin film is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass, based on the total amount (100% by mass) of the other resin film. The content may be 80% by mass or more, 90% by mass or more, or 95% by mass or more. Further, the other resin film may contain other components other than the resin.

When the above resin film is used with an adhesive layer or other resin film laminated via an adhesive layer on one side, an adhesive layer or an adhesive layer (particularly an adhesive layer) is provided on the other side. It is preferable that they are laminated (formed). In this case, the resin film can be laminated with the other resin film on one side, and the other side can be bonded to the adherend.

[Method for manufacturing resin film]
The resin film can be manufactured by a method including a heating step of heating the raw material film so that the ratio [heat shrinkage rate/high humidity expansion rate] falls within the above range. The resin film manufacturing method may include steps other than the heating step.

(Heating process)
The raw material film is appropriately selected depending on the type of the resin film. The raw material film may be a non-stretched film or a film stretched in at least one direction (stretched film), but is preferably a non-stretched film.

In the heating step, it is preferable to heat the raw material film while applying tensile stress. By heating in this manner, a resin film having the above ratio [heat shrinkage rate/high humidity expansion coefficient] within the above range can be easily produced. In particular, by appropriately adjusting the tensile stress depending on the type of the raw material film, a resin film having the ratio [heat shrinkage rate/high humidity expansion rate] within the above range can be easily produced.

The direction in which the tensile stress is applied is preferably at least one direction of the raw material film, more preferably two directions, and still more preferably two orthogonal directions. Among these, it is particularly preferable to heat the resin film while applying tensile stress in the MD direction and/or TD direction.

The above tensile stress can be applied by a known or commonly used method. For example, in the heating step, tensile stress may be applied and heated by stretching in the MD direction. In a method such as a roll-to-roll method in which a raw material film is heated while being continuously transported using transport rolls, tensile stress can be applied in the MD direction by the tensile stress generated during transport by the transport rolls. Further, in the TD direction, heating may be performed while applying tensile stress by stretching such as tenter stretching. Alternatively, heating may be performed while holding both ends in the MD direction or both ends in the TD direction with chucks or the like and pulling them outward in the MD direction and/or outward in the TD direction, or while fixing them.

The above tensile stress is adjusted appropriately depending on the type and properties of the resin of the raw material film, but is preferably 10N or more, more preferably 30N or more, even more preferably 50N or more, 60N or more, 80N or more, 100N or more. Good too. Further, the tensile stress is preferably 500N or less, more preferably 450N or less, still more preferably 400N or less. When the tensile stress is within the above range, a resin film having the above ratio [heat shrinkage rate/high humidity expansion coefficient] within the above range can be easily produced.

When applying tensile stress in two directions, the tensile stress in one direction (especially in the MD direction) is preferably 50N or more, more preferably 80N or more, and even more preferably 100N or more. Further, the tensile stress in one direction (particularly in the MD direction) is preferably 500N or less, more preferably 450N or less, even more preferably 400N or less. Further, the tensile stress in the other direction (particularly the TD direction) is preferably 10N or more, more preferably 30N or more, even more preferably 50N or more, and may be 60N or more, 80N or more, or 100N or more. Further, the tensile stress in the other direction (particularly the TD direction) is preferably 500N or less, more preferably 450N or less, even more preferably 400N or less.

The heating temperature and heating time in the heating step are appropriately selected depending on the type of raw material film. The heating temperature is, for example, 60 to 200°C, preferably 80 to 180°C, more preferably 100 to 160°C. The heating time is, for example, 10 seconds to 30 minutes, preferably 30 seconds to 15 minutes, and more preferably 1 minute to 10 minutes.

The above-mentioned heating can be performed by a known or commonly used heating method. Among these, it is preferable that the heating is performed by applying hot air from at least one side (preferably both sides) of the raw material film. According to such a heating method, the raw material film can be heated more uniformly.

It is preferable that the above-mentioned heating is carried out in a state where other layers such as a pressure-sensitive adhesive layer or an adhesive layer are not laminated, and it is particularly preferable to carry out the heating on the raw material film alone. In this case, a resin film having the ratio [heat shrinkage rate/high humidity expansion rate] within the above range can be easily produced.

It is preferable that the heating is performed while conveying the raw material film. A resin film can be efficiently produced by heating the raw material film while conveying it.

(Unwinding process)
The manufacturing method may include, before the heating step, a step of continuously unwinding the raw material film in the longitudinal direction from a rolled body around which the raw material film is wound (unwinding step). When the above-mentioned unwinding step is provided, the above-mentioned raw material film can be continuously fed into an oven or the like and heated while being conveyed, and a resin film can be efficiently produced.

(winding process)
The manufacturing method may include a step of winding up the film after the heating step while pulling it in the longitudinal direction to obtain a roll-shaped original resin film (winding step). By providing the above-mentioned winding process, tensile stress can be generated in the longitudinal direction (MD direction) of the film during winding, so tensile stress can be easily applied to the raw material film during heating, and production efficiency can be increased. Excellent in

An embodiment of the method for manufacturing a resin film of the present invention is shown in FIG. As shown in FIG. 3, first, the raw material film 1' is unwound from the wound body 11 while being held between rolls 61 and 62 (unwinding step). If a protective film 41 is attached to the raw material film 1', the protective film 41 is peeled off by a roll 62 before heating, and the raw material film 1' itself is continuously put into the oven 5. A plurality of hot air blowers 51 are installed inside the oven 5. The raw material film 1' is pulled and conveyed by rolls 63 and 64 located outside the exit of the oven 5. By making the rotational speed of the rolls 63 and 64 faster than the rotational speed of the rolls 61 and 62, tensile stress can be applied to the raw material film 1' in the MD direction. For this reason, the raw material film 1' is subjected to tensile stress in the oven 5, and both sides (the upper surface and the lower surface) of the raw material film 1' are heated by the hot air blown from the hot air blower 51 (heating step). . The film taken out from the oven 5 is cooled to room temperature, and while being conveyed while being sandwiched between rolls 63 and 64, the protective film 42 is attached again and wound up (winding process). In this way, the rolled body 12 in which the resin film 1 is wound can be obtained.

[Adhesive layer or adhesive layer]
In this specification, an adhesive layer or an adhesive layer may be referred to as an "adhesive layer, etc.". In addition, in this specification, "adhesion" refers to the property that two surfaces can be brought into close contact with each other based on the cohesive force based on the chemical structure of the composition and can be peeled off if necessary by external pressure sensitivity (for example, minute pressure). refers to things related to On the other hand, "adhesion" refers to a property in which a composition undergoes a chemical reaction (curing) to produce a cured product, is not expected to peel off, and can firmly bond two surfaces together. Moreover, in this specification, the "adhesive layer" is a layered adhesive layer that does not have fluidity, and the "adhesive layer" is a layered adhesive layer that does not have fluidity.

Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer containing a polymer capable of exhibiting tackiness and/or adhesive properties. The above-mentioned polymers may contain only one type, or may contain two or more types. Examples of the polymer include thermoplastic resins, thermosetting resins, active energy ray-curable resins, and the like. An adhesive layer or the like containing a thermoplastic resin can exhibit adhesiveness that allows it to adhere tightly under pressure from the outside, for example. An adhesive layer or the like containing a thermosetting resin can be bonded to an adherend by being cured, for example, by heating.

Examples of the thermosetting resin include both thermosetting resins (thermosetting resins) and resins obtained by curing the thermosetting resins. The thermosetting resin has a thermosetting functional group. The number of thermosetting functional groups in the thermosetting resin is preferably 2 or more (for example, 2 to 4). Examples of the thermosetting resin include phenol resins, epoxy resins, urethane resins, melamine resins, alkyd resins, and silicone resins.

Examples of the thermoplastic resin include polystyrene resin, vinyl acetate resin, polyester resin, polyolefin resin (polyethylene resin, polypropylene resin composition, etc.), polyimide resin, acrylic resin, rubber (natural rubber , synthetic rubber, mixtures thereof, etc.), polyether resins, polyamide resins, fluorine resins, and the like. Among these, acrylic resins are preferred because they can impart cohesive force and appropriate flexibility to the adhesive layer and the like.

The adhesive layer and the like preferably contain an acrylic resin as a base polymer. Note that in this specification, the base polymer refers to a main component of the polymer components in a pressure-sensitive adhesive or an adhesive constituting the pressure-sensitive adhesive layer, for example, a polymer component contained in an amount exceeding 50% by mass. The content of the base polymer in the adhesive layer, etc. is preferably 60% by mass or more, more preferably 70% by mass or more, based on 100% by mass of the total amount of the adhesive layer, etc.

The design of acrylic resin varies depending on the purpose, and it is necessary to match the target values of mechanical properties such as flexibility and modulus of elasticity, thermal properties such as glass transition point, and adhesive properties such as adhesive strength and adhesion. Accordingly, it is preferable to appropriately select the monomer species, copolymerization composition ratio, molecular weight, molecular weight distribution, crosslinking agent, blending composition ratio, etc.

Acrylic resin is a resin containing an acrylic monomer (a monomer having a (meth)acryloyl group in the molecule) as a monomer component constituting the resin. That is, the acrylic resin includes a structural unit derived from an acrylic monomer. The acrylic resin is preferably a polymer containing a (meth)acrylic acid alkyl ester as a monomer component constituting the polymer. In addition, in this specification, "(meth)acrylic" represents "acrylic" and/or "methacrylic" (either or both of "acrylic" and "methacrylic"), and the others are the same. .

It is preferable that the acrylic resin is a polymer containing the largest mass proportion of structural units derived from (meth)acrylic esters. Examples of the above (meth)acrylic esters include hydrocarbon group-containing (meth)acrylic esters. The above-mentioned hydrocarbon group-containing (meth)acrylic esters include alicyclic esters such as (meth)acrylic acid alkyl esters and (meth)acrylic acid cycloalkyl esters having a linear or branched aliphatic hydrocarbon group. Examples include (meth)acrylic esters having a hydrocarbon group, and (meth)acrylic esters having an aromatic hydrocarbon group such as aryl (meth)acrylic esters. The above hydrocarbon group-containing (meth)acrylic esters may be used alone or in combination of two or more.

Examples of the (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and (meth)acrylate. ) Isobutyl acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate , octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylic acid Isodecyl, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth)acrylic acid Examples include hexadecyl, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

Among the above-mentioned (meth)acrylic acid alkyl esters, ( Preferred are meth)acrylic acid alkyl esters. When the number of carbon atoms is within the above range, the glass transition temperature of the acrylic resin can be easily adjusted and the adhesiveness can be made more appropriate.

Examples of the (meth)acrylic ester having an alicyclic hydrocarbon group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate, etc. (meth)acrylic esters having a monocyclic aliphatic hydrocarbon ring; (meth)acrylic esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; ) acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl Examples include (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings such as (meth)acrylate.

Examples of the (meth)acrylic ester having an aromatic hydrocarbon group include phenyl (meth)acrylate, benzyl (meth)acrylate, and the like.

In order to properly exhibit the basic properties such as tackiness due to the hydrocarbon group-containing (meth)acrylic ester in the adhesive layer, it is necessary to The proportion of the meth)acrylic acid ester is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, based on the total amount (100% by mass) of all the monomer components. In addition, the above ratio may be 99.9% by mass or less, 98% by mass or less, 95% by mass or less, 90% by mass or less, from the viewpoint of copolymerizing other monomer components and obtaining the effects of the other monomer components. It may be less than 80% by mass, or less than 80% by mass.

The above acrylic resin contains structural units derived from other monomer components that can be copolymerized with the above hydrocarbon group-containing (meth)acrylic ester for the purpose of improving cohesion and introducing crosslinking points. It's okay to stay. Examples of the other monomer components include hydroxy group-containing monomers, nitrogen atom-containing monomers, carboxy group-containing monomers, acid anhydride monomers, keto group-containing monomers, alkoxysilyl group-containing monomers, glycidyl group-containing monomers, and sulfonic acid group-containing monomers. Examples include polar group-containing monomers such as monomers and phosphoric acid group-containing monomers. Each of the above other monomer components may be used alone or in combination of two or more.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, Examples include 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

Examples of the nitrogen atom-containing monomer include amide group-containing monomers, amino group-containing monomers, cyano group-containing monomers, and monomers having a nitrogen atom-containing ring. Examples of the amide group-containing monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N- -Methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, and the like. Examples of the amino group-containing monomer include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate. Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, and N-vinylpyrazine. , N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine and the like.

Examples of the carboxy group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride.

Examples of the keto group-containing monomer include diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate, and the like.

Examples of the alkoxysilyl group-containing monomer include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-( Examples include meth)acryloxypropylmethyldiethoxysilane.

Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and the like.

Examples of the sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acrylamidopropanesulfonic acid. ) Acryloyloxynaphthalene sulfonic acid and the like.

Examples of the phosphoric acid group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

The total proportion of the polar group-containing monomers in the total monomer components (100% by mass) constituting the acrylic resin is not particularly limited, but from the viewpoint of better exhibiting the effect of using the polar group-containing monomers, It is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more. It may be. Moreover, from the viewpoint of obtaining an adhesive layer having appropriate flexibility, the total of the above proportions is preferably 50% by mass or less, more preferably 40% by mass or less.

The monomer components constituting the acrylic resin may further contain other monomers. Examples of the other monomers mentioned above include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrene (α-methylstyrene, etc.), and vinyltoluene; ethylene, propylene, etc. , isoprene, butadiene, isobutylene, etc.; chlorine-containing monomers such as vinyl chloride, vinylidene chloride; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate; methyl vinyl ether, ethyl vinyl ether, etc. Examples include vinyl ether monomers.

The proportion of the other monomers in the total amount of 100% by mass of all monomer components constituting the acrylic resin may be, for example, 0.05% by mass or more, and 0.5% by mass or more. The above ratio may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less, and may be substantially free.

The acrylic resin can be obtained by polymerizing monomer components containing the acrylic monomer. These polymerization methods include, but are not particularly limited to, solution polymerization methods, emulsion polymerization methods, bulk polymerization methods, thermal polymerization methods, and polymerization methods using active energy ray irradiation (active energy ray polymerization methods). Among these, bulk polymerization, thermal polymerization, and active energy ray polymerization are preferred from the viewpoint of transparency of the adhesive layer, cost, and the like. Further, the acrylic resin obtained may be a random copolymer, a block copolymer, a graft copolymer, or the like.

Various common solvents may be used in polymerizing the monomer components. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane. alicyclic hydrocarbons; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The above solvents may be used alone or in combination of two or more.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in the radical polymerization of the monomer components are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the acrylic resin can be controlled by the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted as appropriate depending on the types of these.

As the polymerization initiator used for polymerizing the monomer components, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc. can be used depending on the type of polymerization reaction. The above polymerization initiators may be used alone or in combination of two or more.

The thermal polymerization initiator is not particularly limited, but includes, for example, an azo polymerization initiator, a peroxide polymerization initiator (for example, a persulfate such as dibenzoyl peroxide, tert-butyl permaleate, potassium persulfate, etc.). , benzoyl peroxide, hydrogen peroxide, etc.), substituted ethane initiators such as phenyl-substituted ethane, aromatic carbonyl compounds, redox polymerization initiators, and the like. Among these, the azo polymerization initiator disclosed in JP-A No. 2002-69411 is preferred. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, dimethyl 2,2'-azobis(2-methylpropionic acid), Examples include 4,4'-azobis-4-cyanovaleric acid. The amount of the thermal polymerization initiator to be used may be any normal amount, for example, selected from the range of 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the monomer component. can do.

The above photopolymerization initiators are not particularly limited, but include, for example, benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, and photopolymerization initiators. Examples include active oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and the like. Other examples include acylphosphine oxide photopolymerization initiators and titanocene photopolymerization initiators. Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, Examples include anisole methyl ether. Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-(t-butyl ) dichloroacetophenone, etc. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one, and the like. It will be done. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)-oxime. Examples of the benzoin-based photopolymerization initiator include benzoin. Examples of the benzyl-based photopolymerization initiator include benzyl. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone. Examples of the above-mentioned acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like. . Examples of the titanocene photopolymerization initiator include bis(η ⁵ -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl). ) titanium, etc. The amount of the photopolymerization initiator to be used may be any normal amount, for example, selected from the range of 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the monomer component. can do.

The adhesive layer and the like may contain other components other than the above-mentioned components, if necessary. Examples of the other components mentioned above include curing catalysts, crosslinking agents (including polyfunctional (meth)acrylates), crosslinking accelerators, polymerization initiators, tackifier resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.) ), oligomers, anti-aging agents, fillers (metal powder, organic fillers, inorganic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents , surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, sensitizers, polymerization inhibitors, granules, foils, flame retardants, silane coupling agents, ion trapping agents, and the like. The above-mentioned other components may be used alone or in combination of two or more.

The above-mentioned crosslinking agent is not particularly limited as long as it crosslinks polymers, but includes polyisocyanate compounds, epoxy compounds, polyol compounds (such as polyphenol compounds), aziridine compounds, melamine crosslinking agents, and polyfunctional (meth)acrylates. can be mentioned. Examples of polyfunctional (meth)acrylates include (meth)acrylic acid esters having two or more functionalities, such as 1,6-hexanediol diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, Examples include pentaerythritol tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate. The above crosslinking agents may be used alone or in combination of two or more.

Examples of the silane coupling agent include, but are not limited to, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-phenyl-aminopropyltrimethoxysilane. Examples include. The above-mentioned silane coupling agents may be used alone or in combination of two or more.

As the colorant, a black colorant is preferable. As the black colorant, known or commonly used colorants (pigments, dyes, etc.) for producing a black color can be used. For example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, etc.) can be used. , pine smoke, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide , chromium complexes, anthraquinone colorants, zirconium nitride, etc. Further, a colorant that functions as a black colorant by combining a colorant exhibiting a color other than black may be used.

When the adhesive layer, etc. contains a colorant, the content of the colorant in the adhesive layer, etc. is preferably 0.2% by mass or more, more preferably, based on 100% by mass of the total amount of the adhesive layer, etc. is 0.4% by mass or more. Further, the content of the colorant is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less. The above content ratio may be appropriately set depending on the type of colorant and desired properties.

The thickness of the adhesive layer, etc. (the total thickness of the adhesive layer, etc. on one side) is not particularly limited, but is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. When the thickness is 10 μm or more, the adhesive strength and adhesion to the adherend are excellent. The thickness of the adhesive layer and the like is, for example, 500 μm or less, preferably 300 μm or less. When the thickness is 500 μm or less, the thickness of the adhesive sheet etc. can be made thinner. Note that the thicknesses of the adhesive layers and the like on both sides may be the same or different.

The adhesive layer and the like may be in any form, for example, an emulsion type, a solvent type (solution type), an active energy ray-curable type, a heat melt type (hot melt type), etc. Among these, solvent-type and active energy ray-curable types are preferred since they are easy to obtain adhesive layers with excellent productivity.

Examples of the active energy rays include ionizing radiation such as α rays, β rays, γ rays, neutron beams, and electron beams, and ultraviolet rays, with ultraviolet rays being particularly preferred. That is, the active energy ray-curable adhesive layer and the like are preferably ultraviolet-curable adhesive layers.

The above-mentioned adhesive layer etc. can be formed by, for example, applying (coating) an adhesive composition or an adhesive composition for forming the adhesive layer etc. onto a release liner, and applying the resulting adhesive composition layer or adhesive. The composition layer may be dried and cured, or the pressure-sensitive adhesive composition or adhesive composition described above may be applied (coated) onto a release liner, and the resulting pressure-sensitive adhesive composition layer or adhesive composition layer may be exposed to active energy rays. It can be manufactured by irradiating and curing. Moreover, if necessary, it may be further dried by heating.

[Adhesive sheet and adhesive sheet]
A pressure-sensitive adhesive sheet or an adhesive sheet can be produced using the resin film of the present invention as a base material. In this specification, a pressure-sensitive adhesive sheet or an adhesive sheet may be referred to as an "adhesive sheet, etc.". Furthermore, in the present specification, the term "adhesive sheet" includes a tape-like material, that is, an "adhesive tape", and the same applies to the "adhesive sheet". The above-mentioned adhesive sheet may be a double-sided adhesive sheet, etc., in which both sides have an adhesive layer, etc., or a single-sided adhesive sheet, etc., in which only one side has an adhesive layer, etc. .

The pressure-sensitive adhesive sheet and the like include a resin film of the present invention as a base material and a pressure-sensitive adhesive layer formed on at least one surface of the base material. In addition, the above-mentioned "base material (base material layer)" refers to a support, and when using (applying) an adhesive sheet etc. to an adherend, the "base material (base material layer)" is attached to an adherend together with an adhesive layer etc. This is the part where it is done. A release liner that is peeled off when an adhesive sheet or the like is used (applied) is not included in the base material.

When the above-mentioned adhesive sheet etc. are a single-sided adhesive sheet etc., the adhesive layer etc. provided may be either an adhesive layer or an adhesive layer, but it is preferable that it is an adhesive layer.

When the above-mentioned pressure-sensitive adhesive sheet etc. is a double-sided pressure-sensitive adhesive sheet etc., both of the pressure-sensitive adhesive layers provided on both sides of the base material may be pressure-sensitive adhesive layers, or both may be adhesive layers. Although one may be an adhesive layer and the other an adhesive layer, it is preferable that at least one is an adhesive layer. In addition, the adhesive layers provided on both sides of the base material in the above-mentioned adhesive sheet, etc. may be the same adhesive layer, etc., or may be adhesive layers, etc. that have different compositions, thicknesses, physical properties, etc. Good too. The adhesive layers and the like provided on both sides of the base material may each be a single layer, or may be a multilayer consisting of layers that are the same or have different compositions, thicknesses, physical properties, and the like.

The thickness of the adhesive sheet etc. is preferably 100 to 1500 μm, more preferably 120 to 1200 μm, and even more preferably 150 to 1000 μm. In addition, the thickness of the above-mentioned adhesive sheet, etc. is the thickness from the adhesive side or adhesive surface to the exposed surface of the base material in the case of a single-sided adhesive sheet, etc., and the thickness from one adhesive side or adhesive surface to the other in the case of a double-sided adhesive sheet, etc. The thickness up to the adhesive side or bonding surface of the adhesive, that is, the thickness of the adhesive or adhesive, not including the release liner.

The pressure-sensitive adhesive sheet and the like may have a release liner provided on the surface of the pressure-sensitive adhesive layer (adhesive surface or adhesive surface) until use. In addition, when the above-mentioned adhesive sheet, etc. is a double-sided adhesive sheet, each adhesive surface or adhesion surface may be protected by two release liners, or one release liner with release surfaces on both sides. Accordingly, it may be protected by being wound into a roll (wound body). A release liner is used as a protective material for an adhesive layer, etc., and is peeled off when it is attached to an adherend. Note that the release liner does not necessarily have to be provided.

Examples of base materials for the release liner include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polyethylene naphthalate film. Butylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, Examples include fluororesin films. Also included are these crosslinked films. Furthermore, a laminated film of these may be used.

The release surface of the release liner (particularly the surface in contact with the adhesive layer, etc.) is preferably subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

The thickness of the release liner is not particularly limited, but is, for example, about 20 to 150 μm.

The adherend to which the above-mentioned pressure-sensitive adhesive sheet or the like is bonded is not particularly limited, but includes the other resin films mentioned above. Moreover, when the above-mentioned pressure-sensitive adhesive sheet or the like is a double-sided pressure-sensitive adhesive sheet or the like, one surface may be bonded to the other resin film as the adherend, and the other surface may be bonded to the other adherend.

FIG. 4 shows an embodiment in which the adhesive sheet and the like are bonded to an adherend. The adhesive sheet etc. 13 shown in FIG. and an adhesive layer 24 formed on the surface. Another resin film 33 is bonded to the adhesive layer etc. 23. The adhesive layer 24 side of the adhesive sheet 13 to which another resin film 33 is attached is attached to the adherend 7. In this way, the other resin film 33 is fixed to the adherend 7 via the adhesive sheet or the like 13. By using the resin film 1 of the present invention as a base material of the adhesive sheet etc. 13, when exposed to a high temperature and high humidity environment in the state shown in FIG. 4, between the other resin film 33 and the adhesive layer etc. 23, Peeling is less likely to occur between the resin film 1 and the adhesive layer 23, and between the resin film 1 and the adhesive layer 24.

The use of the pressure-sensitive adhesive sheet and the like is not particularly limited, and can be used for any purpose. For example, it can be used for optical purposes, that is, for bonding to optical members. Excellent reliability can be achieved by using the above-mentioned pressure-sensitive adhesive sheet etc. for optical applications. For example, the other resin film as an adherend is laminated on one side of the adhesive sheet etc. through an adhesive layer etc., and the other side is laminated with another resin film such as a glass substrate through an adhesive layer etc. It can be used by attaching it to a body.

The adhesive sheet and the like are used, for example, when attaching (installing) various members or parts to predetermined parts (for example, a housing, a front plate, a window part, etc.) in optical members such as electrical and electronic equipment. Note that "electrical and electronic equipment" refers to equipment that falls under at least one of electrical equipment and electronic equipment. Examples of the electrical and electronic devices include image display devices such as liquid crystal displays, organic/inorganic electroluminescent displays, and plasma displays, and portable electronic devices. Examples of the image display device include an image display device in the portable electronic device, an in-vehicle display, and a digital signage (electronic signboard/electronic bulletin board). The above-mentioned image display device may have a form (structure) such as a so-called "rigid type" or a so-called "flexible type", or may be a so-called "foldable type" or a "rollable type", etc. It may be of a form (structure) that can be folded.

Examples of the above-mentioned portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, and various wearable devices (e.g., wristwear type worn on the wrist like a wristwatch, or attached to a part of the body using a clip or strap). Modular types that can be worn, eyewear types that include glasses types (monocular and binocular types, including head-mounted types), clothing types that can be attached to shirts, socks, hats, etc. in the form of accessories, and earphones that can be attached to the ears. digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game devices, electronic dictionaries, electronic notebooks, electronic books, in-vehicle information devices, Examples include portable radios, portable televisions, portable printers, portable scanners, and portable modems. Note that in this specification, "portable" does not mean that it is sufficient to simply be able to carry it; it also means that it has a level of portability that allows an individual (standard adult) to carry it relatively easily. shall mean.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples in any way.

Manufacturing example 1
[Preparation of adhesive (1)]
(Preparation of acrylic prepolymer solution A)
In a separable flask equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube, 78 parts by mass of 2-ethylhexyl acrylate (2-EHA) and N-vinyl-2-pyrrolidone were added as monomer components. (NVP) 18 parts by mass, 2-hydroxyethyl acrylate (HEA) 5 parts by mass, photopolymerization initiator (trade name "omnirad 184", manufactured by IGM Resins Italia Srl) 0.035 parts by mass, and photopolymerization initiator After adding 0.035 parts by mass of (trade name "omnirad 651", manufactured by IGM Resins Italia Srl), nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, ultraviolet rays were irradiated at 5 mW/cm ² to perform polymerization, and the reaction rate was adjusted to 5 to 15% to obtain acrylic prepolymer solution A.

(Preparation of acrylic oligomer solution)
100 parts by mass of toluene, 60 parts by mass of dicyclopetanyl methacrylate (DCPMA) (trade name "FA-513M", manufactured by Hitachi Chemical Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA), and α-thio as a chain transfer agent. 3.5 parts by mass of glycerol was charged into a four-necked flask. After stirring for 1 hour at 70°C under a nitrogen atmosphere, 0.2 parts by mass of AIBN was added as a thermal polymerization initiator, and the mixture was reacted at 70°C for 2 hours, and then at 80°C for 2 hours. Thereafter, the reaction solution was placed in an atmosphere at a temperature of 130° C., and toluene, a chain transfer agent, and unreacted monomers were removed by drying to obtain a solid acrylic oligomer. This acrylic oligomer had a Tg of 144° C. and a Mw of 4,300. 50 parts by mass of 2-ethylhexyl acrylate (2-EHA) was added to 50 parts by mass of the above acrylic oligomer and dissolved to obtain an acrylic oligomer solution.

(Preparation of adhesive (1))
Acrylic prepolymer solution A (total amount is 100 parts by mass), 17.6 parts by mass of 2-hydroxyethyl acrylate (HEA), 11.8 parts by mass of acrylic oligomer solution, bifunctional monomer (trade name "NK ester"), 0.088 parts by mass of silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane) ) 0.353 parts by mass was added to obtain adhesive (1).

Manufacturing example 2
[Preparation of adhesive (2)]
(Preparation of acrylic prepolymer solution B)
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 67 parts by mass of butyl acrylate (BA), 14 parts by mass of cyclohexyl acrylate (CHA), and 4-hydroxybutyl acrylate were added as monomer components. (4-BHA) 19 parts by mass, photopolymerization initiator (trade name "omnirad 184", manufactured by IGM Resins Italia Srl) 0.09 mass parts, and photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Resins Italia) After adding 0.09 parts by mass (manufactured by Srl), nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, polymerization was carried out by irradiating ultraviolet rays at 5 mW/cm ² , and the reaction rate was adjusted to 5 to 15% to obtain acrylic prepolymer solution B.

(Preparation of adhesive (2))
Acrylic prepolymer solution B (total amount is 100 parts by mass) contains 9 parts by mass of 2-hydroxyethyl acrylate (HEA), 8 parts by mass of 4-hydroxybutyl acrylate (4-HBA), and dipentaerythritol as a polyfunctional monomer. Hexaacrylate (trade name "KAYARAD DPHA", manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.1 part by mass, silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyl) Trimethoxysilane) 0.4 parts by mass was added to obtain an adhesive (2).

Example 1
(Preparation of resin film)
After vacuum drying the product name "DURABIO" (manufactured by Mitsubishi Chemical Corporation, polycarbonate resin) at 80°C for 5 hours, a single screw extruder (manufactured by Shibaura Machinery Co., Ltd., cylinder setting temperature: 250°C), T-die (width A polycarbonate resin film material with a thickness of 180 μm (saturated water absorption rate 1.5 %) was produced.

The raw polycarbonate resin film was heated at 120°C for 5 minutes while applying no tensile stress in the TD direction and 60 N in the MD direction. .5%) was prepared.

(Preparation of double-sided adhesive sheet)
Adhesive (1) was applied to a 38 μm thick release liner (product name "MRF#38", manufactured by Mitsubishi Chemical Corporation) of a polyester film with one side serving as the release surface, and the cumulative amount of light was 3600 mJ using a black light. /cm ² to polymerize. After irradiation, the coated surface is covered with the release side of a 38 μm thick release liner (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation) of a polyester film with one side being the release surface, resulting in a 25 μm thick polyester film. An adhesive layer (1) was prepared.

Adhesive (2) was applied to a 38 μm thick release liner (product name “MRF#38”, manufactured by Mitsubishi Chemical Corporation) of a polyester film with one side serving as the release surface, and the cumulative amount of light was 3600 mJ using a black light. /cm ² to polymerize. After irradiation, the coated surface is covered with the release side of a 38 μm thick release liner (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation) of a polyester film with one side being the release surface, resulting in a 100 μm thick polyester film. An adhesive layer (2) was prepared.

The adhesive layer (1) was attached to one side of the polycarbonate resin film, and the adhesive layer (2) was attached to the other side. In this way, a double-sided pressure-sensitive adhesive sheet was produced in which pressure-sensitive adhesive layers (1) and (2) were laminated on both sides of a polycarbonate resin film, and a release liner was further laminated on both pressure-sensitive adhesive layers.

Example 2
(Preparation of resin film)
The raw polycarbonate resin film produced in Example 1 was heated at 120°C for 5 minutes while applying a tensile stress of 60 N in the MD direction and 60 N on both sides in the TD direction, and the polycarbonate resin film of Example 2 ( A film with a thickness of 177 μm and a saturated water absorption rate of 1.5% was prepared.

(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the polycarbonate resin film of Example 2 was used in place of the polycarbonate resin film of Example 1.

Example 3
(Preparation of resin film)
The raw polycarbonate resin film produced in Example 1 was heated at 120°C for 5 minutes while applying a tensile stress of 390 N in the MD direction and 450 N on both sides in the TD direction, and the polycarbonate resin film of Example 3 ( A film with a thickness of 170 μm and a saturated water absorption rate of 1.5% was prepared.

(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the polycarbonate resin film of Example 3 was used in place of the polycarbonate resin film of Example 1.

Example 4
(Preparation of resin film)
A raw polyester resin film (trade name "Diafoil S100", manufactured by Mitsubishi Chemical Corporation, thickness 188 μm) was heated at 120°C for 5 minutes while applying no tensile stress in the MD direction and applying a tensile stress of 30 N on both sides in the TD direction. The mixture was heated for a minute to produce a polyester resin film of Example 4 (thickness: 186 μm, saturated water absorption: 0.7%).

(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the polyester resin film of Example 4 was used in place of the polycarbonate resin film of Example 1.

Comparative example 1
(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the original polycarbonate resin film produced in Example 1 was used instead of the polycarbonate resin film in Example 1.

Comparative example 2
(Preparation of resin film)
The original polycarbonate resin film produced in Example 1 was heated at 120°C for 5 minutes without applying any tensile stress in both the MD and TD directions, and the polycarbonate resin film of Comparative Example 2 (thickness 183 μm, saturated water absorption rate 1. 5%) was prepared.

(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the polycarbonate resin film of Comparative Example 2 was used in place of the polycarbonate resin film of Example 1.

Comparative example 3
(Preparation of resin film)
The raw polycarbonate resin film produced in Example 1 was heated at 120°C for 5 minutes while applying a tensile stress of 390 N in the MD direction and 600 N on both sides in the TD direction, and the polycarbonate resin film of Comparative Example 3 ( A film with a thickness of 166 μm and a saturated water absorption rate of 1.5% was produced.

(Preparation of double-sided adhesive sheet)
A double-sided adhesive sheet was produced in the same manner as in Example 1, except that the polycarbonate resin film of Comparative Example 3 was used in place of the polycarbonate resin film of Example 1.

Comparative example 4
(Preparation of double-sided adhesive sheet)
Same as Example 1 except that instead of the polycarbonate resin film of Example 1, a raw polyester resin film (trade name "Diafoil S100", manufactured by Mitsubishi Chemical Corporation, saturated water absorption rate 0.7%) was used. A double-sided adhesive sheet was produced in the same manner.

<Evaluation>
The resin films and double-sided pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in the table.

(1) Heating shrinkage rate, high-humidity expansion rate A test piece of 100 mm x 100 mm was cut out from the resin film, and a score was provided at a position 20 mm from the midpoint of the four sides toward the center. The distance a between the points facing each other was measured in a room temperature environment with a temperature of 25° C. and a humidity of 50% RH. Then, to determine the heat shrinkage rate, the sample was placed in an environmental testing machine set at a temperature of 120° C. for 5 minutes. Regarding the high humidity expansion coefficient, the sample was placed in an environmental tester set at a temperature of 85° C. and a humidity of 85% RH for 30 minutes. After that, the test piece was taken out from the environmental testing machine to the room temperature environment of 25°C and humidity 50%RH, which is the same environment as before it was put into the environmental testing machine, and then the plane biaxial dimension measurement (product name "QVA1517- PRO_AE1M (SP)" (manufactured by Mitutoyo Co., Ltd.) was used to measure the distance a' between the scores. Then, for each of the MD direction and the TD direction, the heat shrinkage rate was calculated using the following formula (1), and the high humidity expansion rate was calculated using the following formula (2). The heat shrinkage rate X of the resin film was set as A, and the high humidity expansion coefficient Y was set as B. The table shows the larger value in the MD direction and the TD direction.
Heat shrinkage rate X [%] = (a-a')/a x 100 (1)
High humidity expansion rate Y [%] = (a'-a)/a x 100 (2)

(2) Saturated water absorption rate Measured according to JIS K7209.

(3) Peeling test The release liner is peeled off from the double-sided adhesive sheet to expose the adhesive layer (1), and the exposed adhesive layer (1) is covered with a triacetyl cellulose (TAC) film (product name "KC4UY", Konica Minolta). Co., Ltd.) were pasted together. Then, the release liner was peeled off from the double-sided adhesive sheet to expose the adhesive layer (2), and the exposed adhesive layer (2) was bonded to an acrylic glass plate. In this way, an evaluation sample having a laminated structure of [TAC film/adhesive layer (1)/resin film/adhesive layer (2)/acrylic glass plate] was produced. The above evaluation sample was placed in an environmental testing machine set at a temperature of 85° C. and a humidity of 85% RH for 30 minutes. Thereafter, the evaluation sample was taken out from the environmental testing machine to a room temperature environment with a temperature of 25°C and a humidity of 50% RH. It was visually confirmed whether or not peeling occurred in at least one of the resin film and the adhesive layer (2). The case where no peeling occurred was evaluated as "○", and the case where peeling occurred in at least one location was evaluated as "x".

(4) High-humidity shrinkage rate A test piece of 100 mm x 100 mm was cut out from the TAC film, and a score was provided at a position 20 mm from the midpoint of the four sides toward the center. The distance b between the points facing each other was measured in a room temperature environment with a temperature of 25° C. and a humidity of 50% RH. Then, it was placed in an environmental testing machine set at a temperature of 85° C. and a humidity of 85% RH for 30 minutes. After that, the test piece was taken out from the environmental testing machine to the room temperature environment of 25°C and humidity 50%RH, which is the same environment as before it was put into the environmental testing machine, and then the plane biaxial dimension measurement (product name "QVA1517- PRO_AE1M (SP)" (manufactured by Mitutoyo Co., Ltd.) was used to measure the distance b' between the scores. Then, the high-humidity shrinkage rate was calculated using the following formula (3) for each of the MD direction and the TD direction. The high humidity shrinkage rate Z of the TAC film was defined as C. The table shows the larger value in the MD direction and the TD direction.
High humidity shrinkage Z [%] = (bb')/b x 100 (3)

As shown in Table 1, it was confirmed that peeling did not occur when a resin film having A/B within a specific range was used (Example). On the other hand, peeling occurred when A/B was low and high (Comparative Example). Also, regarding a double-sided adhesive sheet obtained in the same manner as in Example 1, except that an acrylic resin film having an A/B ratio of 0.3 to 2.5 was used in place of the polycarbonate resin in Example 1. It was also confirmed that no peeling occurred in the above (3) peeling test.

Variations of the invention according to the present disclosure will be described below.
[Additional Note 1] This is a resin film that is used with a pressure-sensitive adhesive layer or an adhesive layer laminated on at least one side, and the shrinkage rate when heated for 5 minutes at a temperature of 120°C and a temperature of 85°C and a humidity of 85% RH. A resin film whose expansion rate ratio [former/latter] when stored for 30 minutes in an environment of 0.3 to 2.5.
[Appendix 2] The resin film according to Appendix 1, which is obtained by heat treatment while applying tensile stress in at least one direction.
[Supplementary note 3] The resin film according to supplementary note 1 or 2, which contains as a main component one or more resins consisting of polycarbonate resin, polyester resin, acrylic resin, cellulose resin, and cycloolefin resin.
[Appendix 4] Any of Appendices 1 to 3, which is used by laminating an adhesive layer on one side and laminating the adhesive layer or another resin film on the other side via the adhesive layer. The resin film according to item 1.
[Appendix 5] The ratio of the expansion rate to the contraction rate when the other resin film is stored for 30 minutes in an environment with a temperature of 85°C and a humidity of 85% RH [former/latter] is 1.0 to 3.0. The resin film according to supplementary note 4.

1 Resin film of the present invention 1' Raw material film 10, 13 Adhesive sheet, etc. (adhesive sheet or adhesive sheet)
11, 12 Rolled bodies 21, 22 Adhesive layer 23 Adhesive layer, etc. (adhesive layer or adhesive layer)
24 Adhesive layer 31, 32 Release liner 33 Other resin films 41, 42 Protective film 5 Oven 51 Hot air blower 61, 62, 63, 64 Roll 7 Adherent

Claims (5)

A resin film used with a pressure-sensitive adhesive layer or an adhesive layer laminated on at least one side,
The ratio [former/latter] of the shrinkage rate when heated for 5 minutes at a temperature of 120°C and the expansion rate when stored for 30 minutes in an environment of a temperature of 85°C and a humidity of 85% RH is 0.3 to 2.5. A certain resin film. The resin film according to claim 1, which is obtained by heat-treating a raw material film while applying tensile stress in at least one direction. The resin film according to claim 1 or 2, which contains as a main component one or more resins consisting of polycarbonate resin, polyester resin, acrylic resin, cellulose resin, and cycloolefin resin. The resin film according to claim 1 or 2, which is used by laminating an adhesive layer on one side and laminating another resin film on the other side via the adhesive layer or adhesive layer. A ratio [former/latter] of the expansion rate and the contraction rate when the other resin film is stored for 30 minutes in an environment with a temperature of 85° C. and a humidity of 85% RH is 1.0 to 3.0. 4. The resin film according to 4.

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