JP2015168716A - protective sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective sheet having excellent workability, in a configuration having a base material of a multilayer structure.SOLUTION: A protective sheet with a release liner includes: a sheet-like base material having a multilayer structure with three or more layers; an adhesive layer disposed on one side of the sheet-like base material; and a release liner for protecting an adhesive face of the adhesive layer. The sheet-like base material includes a first layer, and a second layer made from a material different from the first layer. The tensile elasticity of the sheet-like base material is within a range of 1000-4000 MPa. In the protective sheet with a release liner, curl height is less than 3 mm when measured using a test piece of a 60×60 mm square shape.

Description

  The present invention relates to a protective sheet. More specifically, the present invention relates to a protective sheet suitable for a chemical treatment process that masks a non-treatment target portion (a portion where the influence of the chemical solution is to be excluded) when the adherend is treated with the chemical solution.

  Conventionally, an adhesive (also referred to as pressure-sensitive adhesive) sheet (hereinafter also referred to as a protective sheet) has been used for the purpose of protecting an adherend. For example, when a material to be processed (adhered body) such as a glass plate is processed with a chemical solution such as an etching solution, a chemical solution for masking a non-processing target portion (a portion where the influence of the chemical solution is desired to be removed) of the adherend is masked. An adhesive sheet is used as a protective sheet for processing. This type of protective sheet typically has a configuration comprising a substrate and a pressure-sensitive adhesive layer provided on one side thereof, and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is a non-processed portion of an adherend. Used to paste together. Patent document 1 is mentioned as a literature which discloses the prior art regarding the protective sheet for chemical | medical solution processing.

JP2013-040323A

  The protective sheet is required to have various characteristics depending on the application to which the protective sheet is applied. In addition to the required characteristics, it is desirable to have other characteristics that can contribute to workability and the like according to the usage mode. As an example of a method for realizing and improving such various characteristics, there is a method of employing a base material in which a plurality of layers having different characteristics are laminated. For example, in order to prevent the occurrence of wrinkles and wrinkles at the time of pasting and improve the bonding property, it is configured to include a layer having a predetermined tensile elastic modulus, and further, a layer excellent in chemical solution intrusion preventing property is disposed. Thus, it can be expected that a protective sheet having both bonding property and chemical solution penetration preventing property can be obtained. However, when such a base material having a multilayer structure is used, the protective sheet may be curled due to the difference in physical properties of the constituent materials of the respective layers, and an event that the workability is lowered may occur. For example, when the method of adhering the protective sheet to the vacuum suction table and then bonding it to the adherend is adopted, if the protective sheet curls on the vacuum adsorption table, the protective sheet does not adsorb to the above table, and the bonding workability is descend.

  The present invention has been created in view of the above circumstances, and an object thereof is to provide a protective sheet excellent in workability in a configuration including a base material having a multilayer structure.

  According to the present invention, a sheet-like substrate having a multilayer structure of three or more layers, an adhesive layer provided on one side of the sheet-like substrate, and a release liner that protects the adhesive surface of the adhesive layer, A protective sheet with a release liner is provided. The sheet-like base material includes a first layer and a second layer formed from a material different from the first layer. Moreover, the tensile elasticity modulus of the said sheet-like base material exists in the range of 1000-4000 MPa. The protective sheet with a release liner has a curl height of less than 3 mm measured using a 60 mm × 60 mm square test piece.

  Moreover, according to this invention, a protective sheet provided with the sheet-like base material which has a multilayered structure of three or more layers, and the adhesive layer provided in the single side | surface of this sheet-like base material is provided. The sheet-like base material includes a first layer and a second layer formed from a material different from the first layer. Moreover, the tensile elasticity modulus of the said sheet-like base material exists in the range of 1000-4000 MPa. The protective sheet has a curl height of 10 mm or less measured using a 60 mm × 60 mm square test piece.

  According to the above configuration, since the first layer and the second layer constituting the multilayer base material are formed from different materials, the characteristics of these different materials are utilized, and a plurality of layers that are difficult to realize with a single layer structure are provided. It is possible to realize the characteristics or improve the characteristics. Specifically, by setting the tensile elastic modulus of the sheet-like base material within a predetermined range, it is possible to prevent the occurrence of wrinkles and wrinkles at the time of pasting and improve the bonding property, for example, the prevention of chemical solution intrusion, etc. Other properties can be improved. And the structure where the said curl height is below a predetermined value is realizable by making a sheet-like base material into the multilayered structure of three or more layers. Although this protective sheet has a multilayer structure, curling is suppressed and the workability is excellent. In particular, when the method of adhering the protective sheet to the adherend after adsorbing the protective sheet to the vacuum adsorption table is realized, excellent bonding workability is realized. In the present specification, “curling of the protective sheet” means that the protective sheet is not flat but bends to one surface side, and typically warps (that is, curls) and its state. Is included.

  In a preferred embodiment of the protective sheet disclosed herein, the sheet-like base material includes a first surface layer constituting the first surface and a surface (second surface) opposite to the first surface. A two-surface layer, and an intermediate layer disposed between the first surface layer and the second surface layer. By comprising in this way, the protective sheet which is excellent in workability | operativity (typically bonding workability | operativity) is obtained suitably. In this protective sheet, it is preferable that the pressure-sensitive adhesive layer is disposed on the first surface of the sheet-like substrate, and the second surface of the sheet-like substrate constitutes the outer surface of the protective sheet.

In a preferred embodiment of the protective sheet disclosed herein, a ratio (E _1L : E _2L ) between the tensile elastic modulus E _1L of the first surface layer and the tensile elastic modulus E _2L of the second surface layer is 1: It is in the range of 0.5 to 1: 2.

In a preferred embodiment of the protective sheet disclosed herein, the ratio (T _1L / T _2L ) of the thickness T _1L of the first surface layer to the thickness T _2L of the second surface layer is 0.7-1. Within the range of .3.

  In a preferred embodiment of the protective sheet disclosed herein, the tensile modulus of the intermediate layer is in the range of 2500 to 5000 MPa. By comprising in this way, the sheet-like base material which has a predetermined tensile elasticity modulus is obtained suitably.

  In a preferred embodiment of the protective sheet disclosed herein, the first surface layer, the intermediate layer, and the second surface layer constituting the sheet-like substrate are all resin layers. By making a sheet-like base material into a laminate of resin layers, a protective sheet that exhibits a good protective function can be obtained.

  In a preferred embodiment of the protective sheet disclosed herein, the second surface layer is a polyolefin resin layer. By making the second surface layer constituting the outer surface of the protective sheet a polyolefin-based resin layer, the protective sheet has excellent acid resistance. The protective sheet having this configuration is excellent in the invasion prevention property of an acidic chemical solution such as a hydrofluoric acid solution, and can be preferably used as a protective sheet for applications exposed to the chemical solution.

  The protective sheet disclosed here is excellent in workability (typically bonding workability), and has other characteristics (for example, prevention of chemical solution intrusion) by providing a base material having a multilayer structure. obtain. Therefore, for example, a protective sheet in which the bonding workability and the chemical solution intrusion preventing property are compatible is preferably used as a chemical solution protective sheet for masking a non-chemical solution treated portion during chemical treatment.

It is sectional drawing which shows typically the example of 1 structure of a protection sheet. It is sectional drawing which shows the other structural example of a protective sheet typically. It is explanatory drawing which shows the evaluation method of curl height.

  Hereinafter, preferred embodiments of the present invention will be described. Matters necessary for the implementation of the present invention other than matters specifically mentioned in the present specification can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. The “sheet” in this specification includes a film whose thickness is relatively thinner than the sheet and a tape generally referred to as an adhesive tape.

In this specification, the “pressure-sensitive adhesive” refers to a material that exhibits a soft solid (viscoelastic body) state in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure as described above. . The adhesive here is generally defined as “CA Dahlquist,“ Adhesion: Fundamental and Practice ”, McLaren & Sons, (1966) P. 143”, and generally has a complex tensile modulus E ^* (1 Hz). <10 < ⁷ > dyne / cm < ² > material (typically a material having the above properties at 25 [deg.] C.).
Further, in this specification, “main component” refers to a component contained in an amount exceeding 50% by weight unless otherwise specified.

<Configuration of protective sheet>
The protective sheet disclosed herein includes a base material and a pressure-sensitive adhesive layer provided on one surface of the base material. The form of the protective sheet may be, for example, a roll or a single plate with a separator.

  A typical configuration example of the protective sheet is schematically shown in FIG. This protective sheet 1 includes a sheet-like substrate (for example, a resin-made sheet-like substrate) 10 and an adhesive layer 20 provided on one surface (one surface) thereof. The sheet-like base material 10 has a laminated structure of an A layer 11, a B layer 12, and an intermediate layer 15 disposed between the A layer 11 and the B layer 12. The A layer 11 constitutes one surface (first surface) 10A of the sheet-like base material 10, and the B layer 12 is the other surface (second surface. In the sheet-like base material). The surface opposite to the first surface) 10B is configured. The pressure-sensitive adhesive layer 20 is disposed on the first surface 10 </ b> A of the sheet-like substrate 10, and the second surface 10 </ b> B is the outer surface of the protective sheet 1. This protective sheet 1 is used by sticking the surface on the pressure-sensitive adhesive layer 20 side to a portion to be protected of an adherend. As shown in FIG. 2, the protective sheet 1 before use (that is, before application to an adherend) typically has a surface of an adhesive layer 20 (applied surface to the adherend. Hereinafter, also referred to as an adhesive surface). .) May be protected by a release liner 30 having at least a pressure-sensitive adhesive layer 20 side as a release surface. Alternatively, the back surface (second surface) 10B of the base material 10 is a release surface, and the protective layer 10 is wound in a roll shape so that the pressure-sensitive adhesive layer 20 comes into contact with the back surface 10B and the surface (adhesion). The surface may be protected.

<Characteristics of protective sheet>
The protective sheet disclosed herein is characterized by the curl height of a 60 mm × 60 mm square test piece being 10 mm or less. Thereby, even when the protective sheet is stored in a roll shape, for example, it exhibits excellent workability (typically bonding workability). Moreover, the protective sheet in which curling is suppressed as described above is unlikely to cause an event in which an end portion is peeled off after being bonded to an adherend. Therefore, when the protective sheet disclosed here is applied to, for example, a chemical solution processing application, since the end portion is prevented from peeling off, it is possible to suitably prevent the chemical solution from entering the end portion. The curl height is preferably less than 5 mm (eg, less than 3 mm, typically less than 1 mm). It is particularly preferable that the curl height is substantially in the range of 0 to 0.5 mm.

  When the protective sheet disclosed here includes a release liner that protects the adhesive surface, the protective sheet with a release liner provided with the release liner has a curl height of a 60 mm × 60 mm square test piece of less than 3 mm. Characterized by being. The advantages obtained by this are as described above. The curl height is preferably less than 2 mm (for example, less than 1 mm). It is particularly preferable that the curl height is substantially in the range of 0 to 0.5 mm.

  The curl height is a maximum curl height when a protective sheet or a protective sheet with a release liner is cut into a square size of 60 mm × 60 mm, for example, and used as a test piece, and the test piece is placed on a horizontal plane. It is calculated | required by measuring. Specifically, as shown in FIG. 1, when the test piece 100 is curled, it is placed so that the end of the test piece is warped. Usually, any one of the four corners of the test piece shows the maximum value h of the curl height. Therefore, the maximum value h of the curl height can be obtained by measuring the curl height of the four corners. More specifically, the curl height is measured by the method described in Examples described later.

  In a preferable embodiment disclosed herein, the adhesive strength of the protective sheet to glass (to glass) is 0.05 N / 20 mm or more (for example, 0.1 N / 20 mm or more, typically 0.2 N / 20 mm or more). It is preferable that The protective sheet exhibiting the above-mentioned adhesive strength to glass can be preferably used for applications to be attached to glass. In particular, for example, when the glass is used as a protective sheet for chemical treatment that protects a non-target part of the chemical treatment when the chemical treatment is performed on the glass, the problem that the protective sheet is peeled off during the chemical treatment process is more preferably prevented. Can do. The adhesive strength is preferably 3 N / 20 mm or less (for example, 2.5 N / 20 mm or less, typically 2 N / 20 mm or less). As a result, the adhesive strength does not become too high, and the adherend is destroyed (for example, glass breaks, ITO film etc. peels off) when the protective sheet is peeled off after achieving the protection purpose during chemical treatment, for example. Is more preferably prevented.

  The adhesion to glass (vs. glass adhesion) can be measured by the following method. A protective sheet to be used for measurement is cut into a 20 mm × 60 mm square with the MD direction as the longitudinal direction to produce a test piece. The adhesive surface of this test piece is attached to a glass substrate by reciprocating a 2 kg roller once. After holding this in an environment of 25 ° C. and RH 50% for 30 minutes, using a tensile tester (trade name “Tensilon”, manufactured by Shimadzu Corporation), in an environment of 25 ° C. and RH 50% in accordance with JIS Z0237. The 180 ° peel adhesion to glass is measured under the conditions of a peel angle of 180 ° and a tensile speed of 300 mm / min. As the glass substrate, “MICROSLIDE GLASS” (65 mm × 165 mm × 1.3 mm) manufactured by Matsunami Glass Co., Ltd. can be used.

  In a preferred embodiment disclosed herein, the protective sheet may have a change in pH of the sealed pH test paper of less than 1 in 3 hours after being immersed in the HF solution in the evaluation of chemical solution penetration prevention. . The protective sheet satisfying this characteristic can sufficiently prevent the chemical solution from entering the portion to be protected. In the above evaluation test, it is more preferable that the color (pH) of the pH test paper after 3 hours from being immersed in the HF solution does not substantially change.

  The chemical solution intrusion prevention evaluation is measured by the following method. That is, the protective sheet is cut into a size of 80 mm × 30 mm. Next, a 5 mm × 5 mm size pH test paper is placed in the center of the glass substrate, and the cut protective sheet is stacked so that the adhesive surface faces downward so that the pH test paper comes to the center. Paste the roller back and forth. In this way, a sample for evaluation is produced by completely sealing the pH test paper with the protective sheet. After leaving still for 30 minutes, 100 mL of HF20 mol% solution is inject | poured into a plastic container (length 100mm x width 100mm x depth 30mm), and the sample for evaluation obtained above is immersed in this HF solution. The color change (pH change) of the pH test paper after a predetermined time (1 hour and 3 hours) after the immersion is visually confirmed, and the pH is recorded. The above confirmation is performed after taking the sample for evaluation from the HF solution with polyethylene tweezers, washing it thoroughly with water, and drying it at 50 ° C. for 2 hours. As the glass substrate, for example, “MICROSLIDE GLASS” (76 mm × 26 mm × 1.3 mm) manufactured by Matsunami Glass Co., Ltd. may be used.

<Sheet substrate>
The sheet-like substrate used for the protective sheet has a multilayer structure. Moreover, the sheet-like base material having the multilayer structure includes a first layer and a second layer formed of a material different from the first layer. As a result, a plurality of characteristics that are difficult to realize with a single-layer structure can be realized, or the characteristics can be improved. The number of layers of the sheet-like substrate is typically 3 or more (for example, 3 to 9 layers), preferably 3 layers, 4 layers, or 5 layers (more preferably) from the viewpoint of improving a plurality of properties in a balanced manner. Is 3 layers or 5 layers).

  The tensile elastic modulus of the sheet-like substrate is in the range of 1000 to 4000 MPa. Since the sheet-like base material exhibiting the above-described tensile elastic modulus has an appropriate stiffness, it is possible to prevent the occurrence of wrinkles and wrinkles at the time of sticking and improve the bonding property. The tensile elastic modulus is preferably 1100 MPa or more (for example, 1200 MPa or more, typically 1300 MPa or more) from the viewpoint of improving the bonding property. Further, from the viewpoint of followability to the adherend surface, the tensile elastic modulus is preferably 3800 MPa or less (for example, 3500 MPa or less, typically 3000 MPa or less). It is particularly preferable to use a sheet-like substrate having a tensile modulus of 2300 MPa or less (for example, 2100 MPa or less, typically 1500 MPa or less). In a preferred embodiment, the sheet-like substrate has at least one of a tensile elastic modulus to MD (Machine Direction) at room temperature (23 ° C.) and a tensile elastic modulus to TD (Transverse Direction) at the same temperature. (E.g., tensile modulus to MD, preferably both) may be indicative of the above tensile modulus.

  The tensile elastic modulus of the sheet-like base material is a room temperature (23 ° C.) in accordance with JIS K7161: 1994 by cutting out a test piece having a predetermined width along an arbitrary direction (for example, MD or TD) from the sheet-like base material. Can be calculated from linear regression of a stress-strain curve obtained by stretching the test piece in the above-mentioned one direction under the condition of a tensile speed of 300 mm / min. Specifically, it is measured by the method described in Examples described later.

  As a sheet-like substrate used for the protective sheet, a known film-like or sheet-like substrate can be appropriately selected and used. The material of the sheet-like substrate is not particularly limited. For example, a sheet-like substrate formed from a metal material (aluminum, etc.), a sheet-like substrate formed from a resin material (resin sheet substrate), a sheet-like substrate formed from these composite materials (for example, on one side) For example, a plastic sheet on which a metal is deposited can be used. In the present specification, the “resin sheet” typically refers to a non-porous resin film, and is a concept that is distinguished from a woven fabric or a non-woven fabric. As the resin sheet disclosed herein, any of an unstretched resin sheet and a stretched (uniaxially stretched or biaxially stretched) resin sheet can be used.

  The resin component that can be used for the sheet-like base material disclosed herein includes polyolefin resin; polyester resin; polyvinyl chloride (PVC) resin; polyamide resin; polyimide resin; polyphenylene sulfide resin; Resin; Polyurethane resin; Ethylene-vinyl acetate resin; Fluorine-containing resin such as polytetrafluoroethylene; Acrylic resin; These can be used alone or in combination of two or more.

  Preferable examples of the resin component that can be used for the sheet-like substrate include polyolefin resins and polyester resins. Since polyolefin-based resins and polyester-based resins have moderate flexibility, they tend to be excellent in surface shape followability. Therefore, when the protective sheet disclosed here is used as a protective sheet for chemical treatment, there is an advantage that it is difficult to form a chemical solution intrusion path (void) between the adhesive of the protective sheet and the adherend.

  In a preferred embodiment, a polyolefin resin is used as the resin that can be used for the sheet-like base material from the viewpoint of followability to the adherend surface. Polyolefin resins are excellent in acid resistance, and are advantageous materials for preventing the penetration of acidic chemicals. Examples of the acidic chemical solution include a hydrofluoric acid solution used for glass etching, and an acidic plating solution such as a chromium plating solution, a copper sulfate plating solution, a nickel plating solution, an acidic electroless nickel plating solution, and an acidic tin plating solution. Can be mentioned.

  The polyolefin resin may be, for example, an α-olefin homopolymer, a copolymer of two or more α-olefins, a copolymer of one or two or more α-olefins and another vinyl monomer, and the like. Specifically, an ethylene-propylene copolymer such as polyethylene (PE), polypropylene (PP), ethylene propylene rubber (EPR), an ethylene-propylene-butene copolymer, an ethylene-ethyl acrylate copolymer, or the like is used. be able to. More specifically, biaxially stretched polypropylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene, high density polyethylene (HDPE), PE resin blended with two or more types of PE, Examples thereof include PE / PP blend resins obtained by blending PE and PP, and polyolefin resins such as various soft polyolefins. These can be used alone or in combination of two or more.

  A preferred example of the polyolefin resin is a PE resin. The PE-based resin is excellent in flexibility and tends to have excellent followability to the adherend surface having a step. The PE-based resin may be composed mainly of various polymers (ethylene-based polymer) containing ethylene as a component. It may be a PE resin substantially composed of one or two or more ethylene polymers. The ethylene-based polymer may be a homopolymer of ethylene, and is obtained by copolymerizing ethylene as a main monomer with another α-olefin as a secondary monomer (random copolymerization, block copolymerization, etc.). Also good. Preferable examples of the α-olefin include 3 to 10 carbon atoms such as propylene, 1-butene (may be branched 1-butene), 1-hexene, 4-methyl-1-pentene, 1-octene and the like. Of the α-olefin. For example, a PE resin mainly composed of an ethylene polymer in which the α-olefin as the sub-monomer is copolymerized at a ratio of 10 wt% or less (typically 5 wt% or less) can be preferably used.

  In addition, a PE resin containing a copolymer of a monomer having another functional group in addition to a polymerizable functional group (functional group-containing monomer) and ethylene, or a PE system obtained by copolymerizing such a functional group-containing monomer with an ethylene polymer It may be a resin or the like. Examples of the copolymer of ethylene and a functional group-containing monomer include, for example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic. Examples include an ethyl acid copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene- (meth) acrylic acid (that is, acrylic acid and / or methacrylic acid) copolymer crosslinked with a metal ion.

The density of the PE resin is not particularly limited, and may be, for example, about 0.90 to 0.94 g / cm ³ from the viewpoint of surface followability. Preferred PE resins include LDPE and LLDPE. The PE resin may contain one or more LDPE and one or more LLDPE.

  Another preferred example of the polyolefin resin is a PP resin. The PP-based resin may be various polymers (propylene-based polymers) containing propylene as a main monomer (main constituent monomer, that is, a component exceeding 50% by weight of the whole monomer). The concept of the propylene-based polymer here includes homopolypropylene such as isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene; propylene and other α-olefins (typically ethylene and 4 to 10 carbon atoms). Random copolymer (random polypropylene) with one or more selected from among α-olefins of propylene; other α-olefins (typically ethylene and α-having 4 to 10 carbon atoms) A copolymer obtained by block copolymerization of one or more selected from olefins (block polypropylene); and the like.

  The PP resin may be a resin (PP resin) in which the main component of the resin component is a propylene polymer as described above and another polymer is blended as a subcomponent. The other polymer is composed of an α-olefin other than propylene, for example, an α-olefin having 2 or 4 to 10 carbon atoms as a main monomer (main constituent monomer, that is, a component exceeding 50% by weight of the whole monomer). One or more of the polyolefins to be treated. The PP resin may have a composition containing at least PE as the accessory component. The PE content can be, for example, 3 to 50 parts by weight (typically 5 to 30 parts by weight) per 100 parts by weight of PP. The resin component may be a PP resin substantially composed of PP and PE. Further, it may be a PP resin containing at least PE and EPR as subcomponents (for example, a PP resin whose resin component is substantially composed of PP, PE, and EPR). In this case, the content of EPR can be, for example, 3 to 50 parts by weight (typically 5 to 30 parts by weight) per 100 parts by weight of PP.

  Moreover, it is preferable to use a polyester-type resin as resin which can be used for a sheet-like base material from a viewpoint which provides the flexibility suitable for a protection sheet (for example, protection sheet for chemical | medical solution processing), and elasticity. By using a polyester-based resin, a sheet-like base material having a predetermined tensile elastic modulus is suitably realized. Specific examples of the polyester resin include polyethylene terephthalate (PET) resin, polybutylene terephthalate resin, polyethylene naphthalate resin, and the like. These can be used alone or in combination of two or more. Of these, a PET resin is preferable.

  It is preferable that at least one layer constituting the sheet-like substrate is a resin layer made of a resin material. It is more preferable that a plurality of layers (for example, two layers or three layers or more, typically the first layer, the second layer, the A layer, the B layer, the intermediate layer) constituting the sheet-like base material are resin layers, It is more preferable that all the layers constituting the sheet-like substrate are resin layers. As the resin material, one or more of the above-mentioned materials can be appropriately selected and used depending on the purpose.

  It is preferable that the sheet-like base material disclosed here includes a polyolefin resin layer (for example, PE resin) formed from a resin material containing the polyolefin resin (for example, PE resin) as a main component. The proportion of the polyolefin resin (for example, PE resin) in the resin material is preferably 70% by weight or more (for example, 90% by weight or more, typically 95 to 100% by weight). The polyolefin-based resin layer may contain a resin component other than the polyolefin-based resin as long as the function of the resin layer is not significantly impaired, and may not substantially contain a resin component other than the polyolefin-based resin. .

  It is preferable that the sheet-like base material disclosed here includes a polyester resin layer (for example, a PET resin) formed from a resin material containing a polyester resin (for example, a PET resin) as a main component. Thereby, the sheet-like base material which shows a predetermined tensile elasticity modulus is implement | achieved suitably. The proportion of the polyester resin in the resin material is preferably 70% by weight or more (for example, 90% by weight or more, typically 95 to 100% by weight). The polyester-based resin layer may contain a resin component other than the polyester-based resin within a range that does not significantly impair the action of the resin layer, and may not substantially contain a resin component other than the polyester-based resin. .

  The sheet-like base material disclosed here may include a PVC-based resin layer formed from a resin material in which the main component of the resin component (polymer component) is PVC from the viewpoint of improving the step following ability.

  Moreover, the sheet-like base material disclosed here includes, for example, a layer containing an olefin-based polymer alloy and a thermoplastic resin (carbonyl unit-containing thermoplastic resin) containing a carbonyl (C═O) unit in the molecular skeleton. May be included. The polymer alloy may be, for example, a multistage polymerized olefin copolymer (preferably an ethylene / propylene copolymer) polymerized by two or more stages of multistage polymerization. Examples of the carbonyl unit-containing thermoplastic resin include ethylene / vinyl ester copolymers (for example, ethylene-vinyl acetate copolymers), ethylene / unsaturated carboxylic acid copolymers (for example, ethylene-acrylic acid copolymers) and These metal salts can be used. The resin material may contain an inorganic flame retardant.

  The sheet-like base material (typically, each layer of the sheet-like base material) may contain a known additive that can be used for a base material of a protective sheet (for example, a protective sheet for chemical treatment) as necessary. it can. For example, additives such as light stabilizers such as radical scavengers and UV absorbers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, plasticizers, slip agents, antiblocking agents, etc. Can be blended. Each of these additives can be used alone or in combination of two or more. The compounding amount of the additive can be set to the same level as the usual compounding amount in the resin material used for the sheet-like substrate in the application depending on the use of the protective sheet (for example, chemical solution treatment).

  In the technology disclosed herein, for example, the first layer constituting the sheet-like base material is a layer made of a resin material containing a polyolefin resin (for example, PE resin), and the second layer is a polyester resin (for example, PET). (Resin) and a layer made of a resin material.

  In a preferred embodiment, the sheet-like base material has a configuration including an A layer, a B layer, and an intermediate layer disposed between the A layer and the B layer. Each of the A layer, the B layer, and the intermediate layer may be a layer formed from the resin material described above.

  The resin material constituting the A layer preferably contains a polyolefin-based resin (more preferably a PE-based resin) from the viewpoint of followability to the adherend surface and protective properties (typically, prevention of chemical solution intrusion). . Typically, the A layer may be a polyolefin resin layer (more preferably a PE resin layer). Moreover, it is preferable that the said A layer is a layer (1st surface layer) which comprises the 1st surface of a sheet-like base material from a viewpoint of exhibiting the followable | trackability to a to-be-adhered body surface suitably. In that case, an adhesive layer may be disposed on the surface of the A layer.

  The tensile elastic modulus of the A layer (for example, the first surface layer) is not particularly limited, but is about 50 MPa or more (for example, 100 MPa or more, typically 150 MPa or more), and about 5000 MPa or less (for example, 4200 MPa or less, typically It is appropriate that the pressure is 4000 MPa or less. The tensile modulus of the A layer may be about 1000 MPa or less (for example, 600 MPa or less, typically 300 MPa or less) from the viewpoint of surface shape followability. The tensile modulus of the A layer is determined by cutting out a test piece having a predetermined width along an arbitrary direction (preferably MD) from the A layer, and observing the test piece at room temperature (23 ° C.) in accordance with JIS K7161: 1994. It can be calculated from a linear regression of a stress-strain curve obtained by stretching in the above-mentioned one direction under the condition of a tensile speed of 300 mm / min. Specifically, it is measured by the method described in Examples described later. The same applies to the later-described B layer and intermediate layer.

  The thickness of the A layer (for example, the first surface layer) is 5 to 300 μm (for example, 10 to 150 μm, typical) from the viewpoints of handleability, protective properties (for example, prevention of chemical solution intrusion), and followability to the adherend surface. Specifically, it is preferably about 15 to 80 μm.

  The resin material constituting the layer B also preferably contains a polyolefin resin (more preferably a PE resin) from the viewpoint of followability to the surface of the adherend and protection properties (typically, prevention of chemical solution penetration). . Typically, the B layer may be a polyolefin resin layer (more preferably a PE resin layer). In addition, from the viewpoint of suitably exhibiting protective properties such as chemical solution penetration prevention properties, the B layer is a layer (second surface layer) constituting the second surface (surface opposite to the first surface) of the sheet-like substrate. ) Is preferable. In that case, the 2nd surface of a sheet-like base material can comprise the outer surface of a protection sheet. For example, when a protective sheet is used as a protective sheet for chemical treatment, the second surface layer is made of a resin material containing a polyolefin resin (for example, a PE resin), so that a chemical solution (typically an acidic chemical solution) is used. ) Can be suitably prevented at the outer surface of the protective sheet.

  The resin constituting the B layer (for example, the second surface layer) is preferably the same type as the resin constituting the A layer (for example, the first surface layer). Thereby, workability | operativity (typically bonding workability | operativity) improves more. From the viewpoint of followability to the adherend surface and protective properties (typically, prevention of chemical solution penetration), the resin constituting the A layer (for example, the first surface layer) and the B layer (for example, the second surface layer) A polyolefin resin is preferable, and a PE resin is more preferable. Further, from the viewpoint of more suitably realizing excellent workability (typically bonding workability), the resin material constituting the A layer (for example, the first surface layer) is the B layer (for example, the second surface layer). It is preferable that it is the same kind (typically the same composition) as the resin material which comprises.

  The tensile elastic modulus of the B layer (for example, the second surface layer) is not particularly limited, but is about 50 MPa or more (for example, 100 MPa or more, typically 150 MPa or more), and about 5000 MPa or less (for example, 4200 MPa or less, typically It is appropriate that the pressure is 4000 MPa or less. The tensile elastic modulus may be about 1000 MPa or less (for example, 600 MPa or less, typically 300 MPa or less) from the viewpoint of surface shape followability.

  The thickness of the B layer (for example, the second surface layer) is 5 to 300 μm (for example, 10 to 150 μm, typical) from the viewpoints of handleability, protective properties (for example, prevention of chemical solution intrusion), and followability to the adherend surface. Specifically, it is preferably about 15 to 80 μm. In the case where the B layer is the second surface layer constituting the outer surface of the protective sheet, the thickness is 20 μm or more (for example, 35 μm or more, for example) from the viewpoint of suitably exerting the protective properties (for example, prevention of chemical solution intrusion) by the B layer. (Typically 50 μm or more) is more preferable.

In a preferred embodiment, from the viewpoint of workability (typically bonding workability), the tensile elastic modulus _E1L of the A layer (for example, the first surface layer) and the tensile elastic modulus of the B layer (for example, the second surface layer). The ratio to E _2L (E _1L : E _2L ) is in the range of 1: 0.5 to 1: 2. The ratio (E _1L : E _2L ) is preferably 1: 0.7 to 1: 1.4 (eg 1: 0.9 to 1: 1.1, typically 1: 0.95 to 1: 1.05).

In a preferred embodiment, from the viewpoint of workability (typically bonding workability), the thickness T _1L of the A layer (eg, the first surface layer) with respect to the thickness T _2L of the B layer (eg, the second surface layer). The ratio (T _1L / T _2L ) is in the range of 0.5-2. The ratio (T _1L / T _2L ) is preferably in the range of 0.7 to 1.3 (eg 0.9 to 1.1, typically 0.95 to 1.05). In the case where the B layer is the second surface layer constituting the outer surface of the protective sheet, the ratio (T _1L / T _2L ) is set to 0 from the viewpoint of suitably exhibiting the protective properties (for example, prevention of chemical solution intrusion) by the B layer. It is also preferable to set it to 8 or less (for example, 0.7 or less).

  The resin material constituting the intermediate layer preferably includes a polyester-based resin, and more preferably includes a PET-based resin, from the viewpoint of obtaining a protective sheet exhibiting a predetermined tensile elastic modulus. In a preferred embodiment, the intermediate layer is a polyester resin layer (for example, a PET resin layer).

  The tensile elastic modulus of the intermediate layer is not particularly limited, but is about 50 MPa or more (for example, 100 MPa or more, typically 150 MPa or more), and about 5000 MPa or less (for example, 4200 MPa or less, typically 4000 MPa or less). Is appropriate. The tensile elastic modulus may be about 500 MPa or more (for example, 1200 MPa or more, typically 2200 MPa or more) from the viewpoint of bonding properties and the like. In a preferred embodiment, the intermediate layer has a tensile modulus of about 2500 MPa or more (more preferably 2800 MPa or more, such as 3200 MPa or more, typically 3500 MPa or more). By setting the tensile elastic modulus of the intermediate layer within the above range, the tensile elastic modulus of the sheet-like substrate can also be in a suitable range.

  Further, when the tensile elastic modulus of the sheet-like base material is set within a predetermined range by adjusting (typically increasing) the tensile elastic modulus of the intermediate layer, the tensile elastic modulus of the intermediate layer and other layers (for example, A The difference from the tensile elastic modulus of the layer or the B layer may be 100 MPa or more (for example, 800 MPa or more, typically 2200 MPa or more). Thereby, it becomes easy to employ | adopt the material which is excellent in other characteristics (for example, chemical solution penetration prevention property), for example, although it is a low tensile elasticity modulus for layers other than an intermediate | middle layer (for example, A layer and B layer).

  The thickness of the intermediate layer is preferably about 3 to 300 μm (for example, 10 to 150 μm, typically 30 to 80 μm) from the viewpoints of bonding properties and handleability.

  The sheet-like base material disclosed here may further include an additional layer different from them in addition to the A layer, the B layer, and the intermediate layer. The additional layer is not particularly limited, and may be a layer composed of one or more of the above-described materials that can be employed for the sheet-like substrate. The arrangement position of the additional layer is not particularly limited, for example, the adhesion between the A layer (for example, the first surface layer) and the intermediate layer, the adhesion between the B layer (for example, the second surface layer) and the intermediate layer, Furthermore, in order to improve the anchoring property of the pressure-sensitive adhesive layer to the sheet-like substrate, it may be a layer (for example, an undercoat layer or an adhesive layer) disposed between them. Furthermore, a layer disposed on the outer surface of the sheet-like substrate can be an additional layer for the purpose of surface protection such as chemical solution intrusion prevention.

  Multi-layered sheet-like substrates (for example, resin sheets) appropriately employ conventionally known general sheet molding methods (extrusion molding, inflation molding, etc.) and lamination methods (co-extrusion method, dry lamination method, hot melt method). Can be manufactured. In a preferred embodiment, a sheet-like substrate having a multilayer structure can be produced by a dry laminating method. When laminating a sheet-like substrate by the dry laminating method, a polyester-based, urethane-based or rubber-based adhesive can be used as an adhesive for dry laminating. Specific examples of the adhesive include, for example, trade name “TM-250HV / CAT-RT86-L60” manufactured by Toyo Morton, trade name “TM-569 / CAT-RT37-0.8K”, manufactured by Mitsui Chemicals, Inc. Two-curing type dry laminate adhesives such as “Takelac Series” and “Takenate Series”, and “Seika Bond Series” manufactured by Dainichi Seika Kogyo Co., Ltd. Alternatively, a sheet-like base material having a multilayer structure can also be obtained by laminating an adhesive tape having chemical resistance and each layer (for example, A layer, B layer, and intermediate layer). The pressure-sensitive adhesive tape is not particularly limited as long as it has chemical resistance, but one having a pressure-sensitive adhesive layer on at least one surface (preferably one surface) of the support base material is suitable. As a support base material, what was formed from the material (typically resin component) which can be used for the above-mentioned sheet-like base material can be used. This support base material can also be a layer (for example, A layer, B layer, intermediate | middle layer) which comprises a sheet-like base material. Moreover, it does not specifically limit as an adhesive which comprises an adhesive layer, For example, the below-mentioned acrylic adhesive, polyester adhesive, urethane adhesive, rubber adhesive, etc. may be used preferably.

  Treatment (pressure-sensitive adhesive) for improving the adhesiveness to the pressure-sensitive adhesive layer on the surface of the sheet-like substrate on which the pressure-sensitive adhesive layer is provided (the surface on the pressure-sensitive adhesive layer side, the surface to which the pressure-sensitive adhesive is applied) For example, corona discharge treatment, acid treatment, ultraviolet irradiation treatment, plasma treatment, and surface treatment such as primer coating (primer) coating may be performed. A surface treatment such as an antistatic treatment or a peeling treatment may be applied to the surface (rear surface) of the sheet-like substrate opposite to the surface on the pressure-sensitive adhesive layer side, as necessary. As the release treatment, for example, by providing a long-chain alkyl-based or silicone-based release treatment layer on the surface of the base material that is not in contact with the adhesive (the surface opposite to the adhesive layer side surface), the unwinding force of the protective sheet can be increased. Can be lightened. For example, in the protection sheet of the form that protects the adhesive surface until the protective sheet is used by bringing the surface (adhesive surface) of the adhesive layer into contact with the back surface of the sheet-like substrate, the arithmetic on the back surface of the sheet-like substrate The average surface roughness is preferably 0.05 to 0.75 μm (for example, about 0.05 to 0.5 μm, typically about 0.1 to 0.3 μm). Thereby, the smoothness of the pressure-sensitive adhesive surface (pressure-sensitive adhesive surface) can be maintained high until the protective sheet is used, and chemical liquid intrusion from the interface between the pressure-sensitive adhesive and the adherend can be suitably prevented.

  In addition, the surface of the sheet-like base material on which the pressure-sensitive adhesive layer is provided does not affect the surface state of the pressure-sensitive adhesive layer (the surface roughness of the pressure-sensitive adhesive surface) (that is, the arithmetic average surface roughness of the pressure-sensitive adhesive surface) It is preferable to have smoothness that does not cause an increase in For example, the arithmetic average surface roughness of the surface of the sheet-like substrate on the pressure-sensitive adhesive layer side is preferably 1 μm or less, and is 0.05 to 0.75 μm (for example, approximately 0.05 to 0.5 μm, typically approximately 0.1 to 0.3 μm) is more preferable. Thereby, the smoothness of the pressure-sensitive adhesive surface is also improved, and the occurrence of a problem that the chemical solution enters from the interface between the pressure-sensitive adhesive surface and the adherend is prevented.

  The total thickness of the sheet-like substrate can be appropriately selected according to the flexibility (hardness) of the resin sheet used. In general, the total thickness of the sheet-like base material is suitably 500 μm or less, preferably 300 μm or less, more preferably 200 μm or less, from the viewpoint of followability to the adherend surface and the like. Further, from the viewpoint of peeling workability and other handling properties (handling properties), the total thickness is suitably 10 μm or more, preferably 50 μm or more, more preferably 90 μm or more (for example, 100 μm or more, typically Is 130 μm or more). When the total thickness of the sheet-like substrate is increased, it tends to be easy to prevent the infiltration of the chemical solution from the surface of the protective sheet.

<Adhesive layer>
The kind of adhesive which comprises the adhesive layer provided on a sheet-like base material is not specifically limited. For example, acrylic adhesives, rubber adhesives (natural rubbers, synthetic rubbers, mixed systems thereof), silicone adhesives, urethane adhesives, polyester adhesives, polyether adhesives, fluorine adhesives It may be one type or two or more types of pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as pressure-sensitive adhesives. Of these, acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives are preferable from the viewpoints of pressure-sensitive adhesive properties and chemical solution intrusion prevention properties.

  In a preferred embodiment, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive containing an acrylic polymer as a base polymer. The “base polymer” of the pressure-sensitive adhesive refers to the main component of the rubbery polymer contained in the pressure-sensitive adhesive. The rubbery polymer refers to a polymer that exhibits rubber elasticity in a temperature range near room temperature. As the acrylic polymer, for example, a polymer of a monomer component that includes an alkyl (meth) acrylate as a main monomer and may further include a submonomer copolymerizable with the main monomer is preferable. Here, the main monomer means a component occupying more than 50% by weight of the monomer composition in the monomer component.

As the alkyl (meth) acrylate, for example, a compound represented by the following formula (1) can be preferably used.
CH ₂ = C (R ¹ ) COOR ² (1)
Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group. R ² is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, such a range of the number of carbon atoms may be represented as “C _1-20 ”). From the viewpoint of the storage elastic modulus and the like of the pressure-sensitive adhesive, an alkyl (meth) acrylate in which R ² is a chain alkyl group of C _1-14 (eg, C _2-12 , typically C _4-8 ) is preferable, and R Alkyl acrylates in which ¹ is a hydrogen atom and R ² is a C _4-8 chain alkyl group (hereinafter also simply referred to as C _4-8 alkyl acrylate) are more preferable. The alkyl (meth) acrylate in which R ² is a C _1-20 chain alkyl group can be used alone or in combination of two or more. Preferred alkyl (meth) acrylates include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).

In a more preferred embodiment, a monomer in which R ² in the above formula (1) is an alkyl group having 6 or more carbon atoms (for example, 7 or more, typically 8 or more) can be used. Since this monomer has a relatively large number of carbon atoms in the alkyl group, it is highly hydrophobic, and has excellent chemical solution (especially acidic solution such as hydrofluoric acid solution) infiltration prevention properties. For example, alkyl (meth) acrylates in which R ² is a hexyl group, heptyl group, octyl group, nonyl group, 2-ethylhexyl group, propylhexyl group, lauryl or the like are preferable. A particularly preferred alkyl (meth) acrylate is 2EHA.

The blending ratio of the main monomer in all monomer components is preferably 70% by weight or more (for example, 85% by weight or more, typically 90% by weight or more). The upper limit of the mixing ratio of the main monomer is not particularly limited, but is preferably 99.5% by weight or less (for example, 99% by weight or less). In the technique disclosed herein, as the alkyl (meth) acrylate, the ratio of the alkyl (meth) acrylate having an alkyl group having 7 or less carbon atoms in the alkyl (meth) acrylate represented by the above formula (1) is as follows. An embodiment in which the amount is 15% by weight or less (for example, 10% by weight or less, typically 5% by weight or less) can be preferably implemented. The monomer composition of the acrylic polymer may be a composition that substantially does not contain an alkyl (meth) acrylate in which R ² is a C _1-7 alkyl group.

  A submonomer having copolymerizability with the main monomer, alkyl (meth) acrylate, can be useful for introducing a crosslinking point into the acrylic polymer or increasing the cohesive strength of the acrylic polymer. As a secondary monomer, for example, a carboxy group-containing monomer, a hydroxyl group-containing monomer, an acid anhydride group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, a keto group-containing monomer, a monomer having a nitrogen atom-containing ring, an alkoxysilyl group-containing monomer, One type or two or more types of functional group-containing monomers such as imide group-containing monomers and epoxy group-containing monomers can be used. For example, from the viewpoint of improving cohesive strength, an acrylic polymer obtained by copolymerizing a carboxy group-containing monomer and / or a hydroxyl group-containing monomer as the submonomer is preferable. Preferable examples of the carboxy group-containing monomer include acrylic acid and methacrylic acid. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Examples thereof include hydroxyalkyl (meth) acrylates such as acrylates and unsaturated alcohols. Of these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) are more preferable.

  The amount of the submonomer may be appropriately selected so as to achieve a desired cohesive force, and is not particularly limited. Usually, from the viewpoint of achieving a good balance between cohesive strength and other adhesive properties (for example, adhesive strength), the amount of secondary monomer is suitably 0.5% by weight or more based on the total monomer components of the acrylic polymer. And preferably 1% by weight or more. Further, the amount of the submonomer is suitably 30% by weight or less, preferably 10% by weight or less (for example, 5% by weight or less) in the total monomer components.

  The acrylic polymer disclosed herein may be copolymerized with a monomer other than the above (other copolymerizable monomers) as long as the effects of the present invention are not significantly impaired. The other monomers can be used for the purpose of adjusting the glass transition temperature of the acrylic polymer, adjusting the adhesive performance (for example, peelability), and the like. Examples of monomers that can improve the cohesive strength and heat resistance of the pressure-sensitive adhesive include vinyl esters such as vinyl acetate, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, and aromatic vinyl compounds. . Moreover, you may use a polyfunctional monomer as a copolymerizable component for the objective of the crosslinking process of an acrylic polymer, etc. These other monomers can be used alone or in combination of two or more. The amount of the other monomer may be appropriately selected depending on the purpose and application, and is not particularly limited. For example, it is 30% by weight or less (for example, 20% by weight or less, typically 20% by weight or less in the total monomer component of the acrylic polymer). 10% by weight or less) is appropriate.

  The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as synthetic methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, are appropriately employed. be able to. Among these, the solution polymerization method can be preferably used from the viewpoint of water resistance and chemical solution penetration prevention. What is necessary is just to select the monomer supply method and polymerization temperature at the time of performing solution polymerization suitably according to the objective, the material to be used, etc. Preferred examples of the solvent (polymerization solvent) used for solution polymerization include aromatic compounds such as toluene (typically aromatic hydrocarbons), aliphatic or alicyclic hydrocarbons such as ethyl acetate, and acetylacetone. And ketones. The initiator used for the polymerization can be appropriately selected from conventionally known polymerization initiators according to the type of the polymerization method. For example, one or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylpropionitrile can be preferably used. The usage-amount of a polymerization initiator should just be a normal usage-amount, for example, can be selected from the range of about 0.005-1 weight part with respect to 100 weight part of all the monomer components.

  The pressure-sensitive adhesive layer (layer made of pressure-sensitive adhesive) disclosed herein is formed from a water-based pressure-sensitive adhesive composition, a solvent-type pressure-sensitive adhesive composition, a hot-melt pressure-sensitive adhesive composition, and an active energy ray-curable pressure-sensitive adhesive composition. It can be an adhesive layer. The water-based pressure-sensitive adhesive composition refers to a pressure-sensitive adhesive composition in a form containing a pressure-sensitive adhesive (pressure-sensitive adhesive layer forming component) in a water-based solvent (water-based solvent), and is typically dispersed in water. What is called a type pressure-sensitive adhesive composition (a composition in which at least a part of the pressure-sensitive adhesive is dispersed in water) and the like are included. Moreover, a solvent-type adhesive composition means the adhesive composition of the form which contains an adhesive in an organic solvent. The technique disclosed here can be preferably implemented in an aspect including a pressure-sensitive adhesive layer formed from a solvent-type pressure-sensitive adhesive composition from the viewpoint of pressure-sensitive adhesive properties and the like.

  In a preferred embodiment, the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer contains a crosslinking agent. The kind in particular of a crosslinking agent is not restrict | limited, It can select from a conventionally well-known crosslinking agent suitably and can be used. Examples of such a crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, and a metal chelate crosslinking agent. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types. An isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, and a melamine-based cross-linking agent are preferable because adhesion and light peelability can be highly compatible. Isocyanate-based crosslinking agents can be suitably cross-linked with hydroxyl groups, and also have the advantage of being easy to handle and excellent in acid resistance because of excellent storage properties. The amount of the crosslinking agent contained in the pressure-sensitive adhesive composition is not particularly limited, but is about 0.01 to 10 parts by weight (for example, 0.1 to 7 parts by weight, typically 100 parts by weight of the acrylic polymer). Is suitably 0.5-5 parts by weight).

  The pressure-sensitive adhesive composition may further contain a crosslinking accelerator. The kind of crosslinking accelerator can be suitably selected according to the kind of crosslinking agent to be used. In the present specification, the crosslinking accelerator refers to a catalyst that increases the speed of the crosslinking reaction by the crosslinking agent. Examples of the crosslinking accelerator include tin (Sn) -containing compounds such as dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetylacetonate, tetra-n-butyltin, and trimethyltin hydroxide; N, N , N ′, N′-tetramethylhexanediamine, amines such as triethylamine, and nitrogen (N) -containing compounds such as imidazoles. Of these, Sn-containing compounds are preferred. The amount of the crosslinking accelerator contained in the pressure-sensitive adhesive composition is, for example, about 0.001 to 0.5 parts by weight (preferably about 0.001 to 0.1 parts by weight) with respect to 100 parts by weight of the acrylic polymer. It can be.

  In addition, in order to achieve both sealability during protection (for example, during chemical treatment) and releasability after protection (for example, after treatment with chemical), after applying a protective sheet, treatment such as radiation and heat (adhesion reduction processing) ) May be used to reduce the adhesive strength of the adhesive. Examples of such a pressure-sensitive adhesive composition include an internal radiation / thermosetting pressure-sensitive adhesive composition in which a carbon-carbon double bond is introduced into the side chain, main chain or main chain terminal of an acrylic polymer. . The radiation / thermosetting pressure-sensitive adhesive composition has a pressure-sensitive adhesive strength that is reduced by applying a protective sheet having a pressure-sensitive adhesive layer formed using the composition to an adherend and then curing it by irradiation / heating. Can be made. It is also possible to use an additive type radiation curable pressure-sensitive adhesive composition containing an ultraviolet curable monomer component or oligomer component. The radiation curable (typically ultraviolet curable) pressure-sensitive adhesive composition preferably contains a photopolymerization initiator.

  Furthermore, a pressure-sensitive adhesive composition that contains a component that foams or expands by heating, expands the pressure-sensitive adhesive at a predetermined temperature, and reduces the pressure-sensitive adhesive force is also preferred. As such a pressure-sensitive adhesive composition, for example, thermally expandable microspheres (for example, trade name “Microsphere”) in which a substance that is easily gasified by heating, such as isobutane and propane, is encapsulated in an elastic shell. Matsumoto Yushi Seiyaku Co., Ltd. and the like) are included. Further, by using an alkyl (meth) acrylate having an alkyl group having 12 or more carbon atoms as a main monomer constituting the main chain of the acrylic polymer, the pressure-sensitive adhesive is reduced by heating by crystallizing the pressure-sensitive adhesive. It is also possible to adopt a configuration.

  The above-mentioned pressure-sensitive adhesive composition includes a rosin-based resin tackifier, a release modifier, an antistatic agent, a slip agent, an anti-blocking agent, a leveling agent, a plasticizer, a filler, a colorant (pigment, Dyes, etc.), pH adjusters, dispersants, stabilizers, preservatives, anti-aging agents, and the like, may optionally further contain various additives generally used in the field of pressure-sensitive adhesives. About such various additives, a conventionally well-known thing should just be used by a conventional method.

  The pressure-sensitive adhesive layer disclosed herein can be formed by a conventionally known method. The pressure-sensitive adhesive composition can be applied using a conventional coater such as a gravure roll coater. From the viewpoint of promoting the crosslinking reaction and improving the production efficiency, the pressure-sensitive adhesive composition is preferably dried under heating. Depending on the type of support to which the pressure-sensitive adhesive composition is applied, for example, a drying temperature of about 40 ° C. to 150 ° C. can be employed. After drying, an aging treatment may be performed so that the crosslinking reaction further proceeds. The pressure-sensitive adhesive layer disclosed herein is typically formed continuously, but is not limited to such a form, for example, a regular or random pattern such as a dot or stripe. The formed adhesive layer may be sufficient.

  The thickness of an adhesive layer is not specifically limited, It can adjust suitably according to the objective. The thickness of the pressure-sensitive adhesive layer can be, for example, about 1 to 100 μm. A suitable thickness from the viewpoint of adhesion to the adherend surface is 3 μm or more (for example, 5 μm or more, typically 10 μm or more). From the viewpoint of peeling workability, the thickness of the pressure-sensitive adhesive layer is preferably 40 μm or less (typically 30 μm or less). It is preferable that the thickness of the pressure-sensitive adhesive layer is not too large from the viewpoint of suppressing the infiltration of the chemical liquid due to the swelling of the pressure-sensitive adhesive.

  The gel fraction of the pressure-sensitive adhesive constituting the protective sheet is not particularly limited, and may be, for example, 20% by weight or more (for example, 25% by weight or more, typically 30% by weight or more). Thereby, the chemical solution intrusion prevention property from the outer edge of the protective sheet is improved. Further, the cohesive force of the pressure-sensitive adhesive is increased, and contamination such as adhesive residue is less likely to occur when the protective sheet is peeled off. The upper limit of the gel fraction is not particularly limited, but may be about 80% by weight or less (eg, 70% by weight or less, typically less than 60% by weight). When the gel fraction is too high, depending on the configuration of the pressure-sensitive adhesive, the adhesion to the adherend surface tends to be reduced, and chemical liquid intrusion from the interface between the pressure-sensitive adhesive and the adherend may easily occur. The gel fraction can be adjusted by copolymerization composition of acrylic polymer (for example, use of functional group-containing monomer or polyfunctional monomer), molecular weight, cross-linking agent and other additives.

  The gel fraction was measured by wrapping a measurement sample having a weight W1 in a porous sheet made of tetrafluoroethylene resin and immersing the sample in ethyl acetate for 1 week at room temperature, then drying the measurement sample and weighing the weight W2 of the ethyl acetate insoluble matter. And W1 and W2 are calculated by substituting into the following formula: gel fraction [%] = W2 / W1 × 100; As the porous sheet made of tetrafluoroethylene resin, a trade name “Nitoflon (registered trademark) NTF1122” manufactured by Nitto Denko Corporation can be used.

<Release liner>
The protective sheet may be in the form of a protective sheet with a release liner in which a release liner is disposed on the surface of the pressure-sensitive adhesive layer before use (before application to an adherend). A conventional release paper or the like can be used as the release liner, and is not particularly limited. For example, a low-adhesiveness of a release liner having a release treatment layer on the surface of a liner substrate such as a resin sheet such as PET or paper, or a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin resin (polyethylene, polypropylene, etc.) A release liner made of a material can be used. The release treatment layer may be formed, for example, by surface-treating the liner base material with a release treatment agent such as silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide. The thickness of the release liner is not particularly limited, and may be about 5 to 500 μm (for example, about 10 to 200 μm, typically about 30 to 200 μm).

  In addition, the arithmetic average surface roughness of the surface of the release liner that is disposed on the pressure-sensitive adhesive layer is 0.05 to 0.75 μm (for example, approximately 0.05 to 0.5 μm, typically approximately 0.1 to 0.3 μm) is preferable. Thereby, the smoothness of the pressure-sensitive adhesive surface (adhesive surface) can be kept high until the protective sheet is used. High smoothness of the pressure-sensitive adhesive surface is advantageous in preventing chemical solution from entering from the interface between the pressure-sensitive adhesive and the adherend.

  The total thickness of the protective sheet disclosed here (including the pressure-sensitive adhesive layer and the sheet-like base material, but not including the release liner) is not particularly limited, and protective properties (for example, prevention of chemical penetration) and handling properties In view of the above, it is appropriate to set the thickness in the range of about 10 to 1000 μm (for example, 30 to 300 μm, typically 60 to 180 μm).

<Application>
The protective sheet disclosed here can be used as a protective sheet for affixing a desired part of an adherend (for example, a glass substrate) and protecting the part. In particular, it is preferable as a protective sheet that is used in a mode of adhering to an adherend after being adsorbed on a vacuum adsorption table. When such a bonding method is adopted, excellent bonding workability by the technique disclosed herein is suitably realized.

  The protective sheet disclosed here takes advantage of the above-described features, for example, when the surface of an adherend (typically a glass substrate) is subjected to a chemical treatment (eg, an etching treatment), for example, It can be preferably used as a protective sheet for chemical treatment that masks a portion where it is desired to eliminate the influence of an etching solution such as an acid solution. Specifically, for example, an etching process for dissolving glass with a chemical solution (etching solution) in order to adjust the thickness of the glass or remove burrs and microcracks formed on the cut end surface of the glass, a chemical solution (etching solution) on the metal surface ) Can be suitably used in etching processes that partially corrode, and plating processes in which connection terminals of circuit boards (printed boards, flexible printed circuit boards (FPC), etc.) are partially plated with a chemical solution (plating solution). . Especially, it can apply especially preferably for the use which etches using acidic chemical | medical solutions, such as a hydrofluoric acid solution. The glass substrate as the adherend is partially made of, for example, a transparent conductive film (for example, ITO (indium tin oxide) film) or FPC, such as those used in tablet computers, mobile phones, and organic LEDs (light emitting diodes). It may be a glass substrate having a surface provided on the surface.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.

<Example 1>
[Preparation of sheet-like substrate]
Low density polyethylene (LDPE, trade name “Petrocene 180”, manufactured by Tosoh Corporation) was molded with an inflation molding machine at a die temperature of 160 ° C. to obtain an LDPE sheet having a thickness of 55 μm and an LDPE sheet having a thickness of 40 μm. . Also, a polyethylene terephthalate (PET) sheet (trade name “Lumirror S10 # 50”, manufactured by Toray Industries, Inc.) having a thickness of 50 μm was prepared.
Using the above LDPE sheet and PET sheet, an LDPE layer (thickness 40 μm) as a first surface layer, a PET layer (thickness 50 μm) as an intermediate layer, and an LDPE layer (thickness 55 μm) as a second surface layer The resin sheet base material in which was laminated in order was produced by a dry laminating method. Specifically, one side of the LDPE sheet serving as the second surface layer was subjected to corona discharge treatment, and the corona treated surface of the LDPE sheet was laminated on one surface of the PET sheet serving as the intermediate layer using an adhesive. In addition, a corona discharge treatment is performed on one side of the LDPE sheet serving as the first surface layer, and the other surface of the PET sheet (the LDPE sheet serving as the second surface layer is laminated on the corona treated surface of the LDPE sheet using an adhesive). The surface on the opposite side of the surface was laminated. In this way, a sheet-like substrate according to Example 1 was produced.

[Preparation of pressure-sensitive adhesive composition]
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, a dropping funnel and a stirring device, toluene as a polymerization solvent, 100 parts of 2-ethylhexyl acrylate and 4 parts of 2-hydroxyethyl acrylate, and an azo polymerization initiator 0.2 part of 2,2′-azobis (2-methylpropionitrile) was added, and polymerization was performed in toluene to obtain a toluene solution of an acrylic polymer. 2 parts of an isocyanate-based crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent and dioctyltin as a crosslinking accelerator for 100 parts of a solid content of an acrylic polymer toluene solution thus obtained. 0.02 part of dilaurate (trade name “Environizer OL-1”, manufactured by Tokyo Fine Chemical Co., Ltd.) is blended, acetylacetone is added as a solvent so as to be 4% of the total amount of solvent, and toluene is further added to adjust the solid content. In addition, an adhesive composition was obtained.

[Preparation of protective sheet]
Corona discharge treatment is performed on one side (first surface) of the sheet-like substrate obtained above, the pressure-sensitive adhesive composition is applied to the corona-treated surface of the sheet-like substrate, and dried at 80 ° C. for 1 minute. An adhesive layer having a thickness of about 20 μm was formed. A silicone-treated surface of a PET sheet (trade name “Diafoil MRF38”, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) having a thickness of 38 μm treated on one side with a silicone-based release agent is bonded to this pressure-sensitive adhesive layer. A protective sheet according to this example was obtained after aging for a day.

<Example 2>
LDPE (trade name “Petrocene 180”, manufactured by Tosoh Corporation) was molded by an inflation molding machine at a die temperature of 160 ° C. to produce two LDPE sheets having a thickness of 20 μm. Moreover, a PET sheet (trade name “Lumirror S10 # 50”, manufactured by Toray Industries, Inc.) having a thickness of 50 μm was prepared. Using the above LDPE sheet and PET sheet, in the same manner as in Example 1, the LDPE layer (thickness 20 μm) as the first surface layer, the PET layer (thickness 50 μm) as the intermediate layer, and the second surface layer A resin sheet base material in which LDPE layers (thickness 20 μm) were sequentially laminated was produced.
A protective sheet according to this example was obtained in the same manner as in Example 1 except that the sheet-like substrate obtained above was used.

<Example 3>
LDPE (trade name “Petrocene 180”, manufactured by Tosoh Corporation) was molded by an inflation molding machine at a die temperature of 160 ° C. to produce two LDPE sheets having a thickness of 40 μm. Moreover, a PET sheet (trade name “Lumirror S10 # 75”, manufactured by Toray Industries, Inc.) having a thickness of 75 μm was prepared. Using the above LDPE sheet and PET sheet, in the same manner as in Example 1, the LDPE layer (thickness 40 μm) as the first surface layer, the PET layer (thickness 75 μm) as the intermediate layer, and the second surface layer A resin sheet base material in which LDPE layers (thickness 40 μm) were sequentially laminated was produced.
A protective sheet according to this example was obtained in the same manner as in Example 1 except that the sheet-like substrate obtained above was used.

<Example 4>
LDPE (trade name “Petrocene 180”, manufactured by Tosoh Corporation) was molded by an inflation molding machine at a die temperature of 160 ° C. to obtain an LDPE sheet having a thickness of 65 μm. Moreover, a PET sheet (trade name “Lumirror S10 # 50”, manufactured by Toray Industries, Inc.) having a thickness of 50 μm was prepared. Using the above LDPE sheet and PET sheet, a resin sheet substrate in which a PET layer (thickness: 50 μm) as a first surface layer and an LDPE layer (thickness: 65 μm) as a second surface layer are laminated is dried. The laminate method was used.
A protective sheet according to this example was obtained in the same manner as in Example 1 except that the sheet-like substrate obtained above was used.

<Example 5>
LDPE (trade name “Petrocene 180”, manufactured by Tosoh Corporation) was molded by an inflation molding machine at a die temperature of 160 ° C. to obtain an LDPE sheet having a thickness of 80 μm. In addition, a PET sheet having a thickness of 100 μm (trade name “Lumirror S10 # 100”, manufactured by Toray Industries, Inc.) was prepared. Using the above LDPE sheet and PET sheet, a PET layer (thickness 100 μm) as the first surface layer and an LDPE layer (thickness 80 μm) as the second surface layer were laminated in the same manner as in Example 4. A resin sheet substrate was prepared.
A protective sheet according to this example was obtained in the same manner as in Example 1 except that the sheet-like substrate obtained above was used.

<Example 6>
High-density polyethylene (HDPE, trade name “Hi-Zex 3300F”, manufactured by Prime Polymer Co., Ltd.) was molded by an inflation molding machine at a die temperature of 200 ° C. to obtain an HDPE sheet having a thickness of 50 μm. Moreover, a PET sheet (trade name “Lumirror S10 # 75”, manufactured by Toray Industries, Inc.) having a thickness of 75 μm was prepared. Using the above HDPE sheet and PET sheet, a PET layer (thickness 75 μm) as the first surface layer and an HDPE layer (thickness 50 μm) as the second surface layer were laminated in the same manner as in Example 4. A resin sheet substrate was prepared.
A protective sheet according to this example was obtained in the same manner as in Example 1 except that the sheet-like substrate obtained above was used.

[Tensile modulus]
The sheet-like base material according to each example and each layer constituting the sheet-like base material were cut into strips having a width of 10 mm with MD as a longitudinal direction to prepare test pieces. A stress-strain curve was obtained by stretching this test piece under the following conditions in accordance with JIS K7161: 1994.
Drawing conditions:
Measuring temperature 23 ° C;
Tensile speed 300 mm / min;
Distance between chucks 50mm;
The tensile modulus was determined by linear regression of the curve between the two defined strains ε1 and ε2. The above measurement was performed using three test pieces cut out from different locations, and the average value thereof was taken as the tensile elastic modulus (MPa) to MD. The results are shown in Table 1.

[Curl height]
For the protective sheet according to each example, the curl heights of both the sheet with the release liner attached and the sheet with the release liner peeled off were measured. Specifically, a protective sheet or a protective sheet with a release liner was cut into a 60 mm × 60 mm square size to obtain a test piece. The test piece was placed on the horizontal surface of a table having a horizontal surface, left at 23 ° C. for 10 minutes, and then the maximum curl height (mm) was measured. When the test piece was curled, the test piece was placed so that the end was warped and measured. The results are shown in Table 1.

[Lamination workability]
Assuming a usage mode in which the protective sheet is fixed to the vacuum suction table and then bonded to the adherend in the fixed state, the one that is smoothly fixed to the vacuum suction table is bonded. The following evaluation was performed considering that it was excellent in workability. That is, the protective sheet according to each example was cut into a rectangular shape of 125 mm × 65 mm to obtain a test piece. The release liner was peeled off from the test piece, and the sample was placed on a vacuum suction table so that the sheet-like substrate side was downward. And the test piece was attracted | sucked with the suction force of about 30 kPa. The state of the test piece at this time was observed and evaluated according to the following criteria. The results are shown in Table 1.
○: Adsorbed on the vacuum adsorption table.
X: It did not adsorb | suck to a vacuum adsorption stand.

  As shown in Table 1, the curl height of the protective sheets according to Examples 1 to 3 was less than 3 mm when the release liner was provided and 10 mm or less when the release liner was not provided, and was well adsorbed to the vacuum suction table. . From these results, it can be seen that a protective sheet having a curl height of not more than a predetermined value is excellent in bonding workability. Moreover, since the tensile elasticity modulus of the protective sheet which concerns on Examples 1-3 is in the range of 1000-4000 Mpa, it is thought that generation | occurrence | production of the wrinkles and wrinkles at the time of affixing can be prevented. On the other hand, the protective sheets according to Examples 4 to 6 had a tensile elastic modulus in the range of 1000 to 4000 MPa, but the curl height exceeded 3 mm when the release liner was provided, and exceeded 10 mm when the release liner was not provided. Good bonding workability could not be realized. These are assumed to be inferior in workability.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2 Protective sheet 10 Sheet-like base material 11 A layer (first surface layer)
12 B layer (second surface layer)
15 Intermediate layer 20 Adhesive layer 30 Release liner

Claims (10)

Protection with a release liner comprising: a sheet-like substrate having a multilayer structure of three or more layers; an adhesive layer provided on one side of the sheet-like substrate; and a release liner for protecting the adhesive surface of the adhesive layer A sheet,
The sheet-like base material includes a first layer and a second layer formed of a material different from the first layer,
The tensile elastic modulus of the sheet-like substrate is in the range of 1000 to 4000 MPa,
The protective sheet with a release liner is a protective sheet with a release liner having a curl height of less than 3 mm measured using a 60 mm × 60 mm square test piece. A protective sheet comprising a sheet-like substrate having a multilayer structure of three or more layers, and an adhesive layer provided on one side of the sheet-like substrate,
The sheet-like base material includes a first layer and a second layer formed of a material different from the first layer,
The tensile elastic modulus of the sheet-like substrate is in the range of 1000 to 4000 MPa,
The said protective sheet is a protective sheet whose curl height measured using a 60 mm x 60 mm square test piece is 10 mm or less.   The sheet-like substrate includes a first surface layer constituting a first surface, a second surface layer constituting a surface (second surface) opposite to the first surface, the first surface layer, and the first surface layer. The protective sheet of Claim 1 or 2 provided with the intermediate | middle layer arrange | positioned between two surface layers.   The protective sheet according to claim 3, wherein the pressure-sensitive adhesive layer is disposed on a first surface of the sheet-like base material, and a second surface of the sheet-like base material constitutes an outer surface of the protective sheet. The ratio (E _1L : E _2L ) between the tensile elastic modulus E _1L of the first surface layer and the tensile elastic modulus E _2L of the second surface layer is in the range of 1: 0.5 to 1: 2. The protective sheet according to claim 3 or 4. The ratio of the thickness _{T 1L} of the first surface layer to the thickness _{T 2L} of the second surface layer _(T 1L _/ T _2L) is in the range of 0.7 to 1.3, according to claim 3-5 The protective sheet according to any one of the above.   The protective sheet according to any one of claims 3 to 6, wherein a tensile elastic modulus of the intermediate layer is within a range of 2500 to 5000 MPa.   The protective sheet according to any one of claims 3 to 7, wherein the first surface layer, the intermediate layer, and the second surface layer constituting the sheet-like substrate are all resin layers.   The protective sheet according to claim 4, wherein the second surface layer is a polyolefin-based resin layer.   The protective sheet as described in any one of Claims 1-9 used as a protective sheet for chemical | medical solution processing for masking a non-chemical-solution process part at the time of chemical | medical solution processing.

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