JP2015193688A - Agent treatment protection sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agent treatment protection sheet which is excellent in agent infiltration prevention property for masking a part where an affection of an agent has to be excluded when an adherend is treated by the agent.SOLUTION: Provided is the agent treatment protection sheet which exhibits agent infiltration prevention property and which comprises: a base material 10 whose water vapor permeation is equal to or less than 5 g/mday and whose thickness is 10-500 μm and comprising a biaxial drawing polypropylene layer; and an adhesive layer 20 disposed on one surface of the base material 10.

Description

  The present invention relates to a protective sheet for chemical solution treatment, and more particularly to a protective sheet for chemical solution treatment that masks a portion where the influence of the chemical solution is to be excluded when the adherend is processed with the chemical solution.

  When an adherend (object to be treated) is treated with a chemical solution, a pressure-sensitive adhesive sheet for masking a portion to be protected (that is, a portion where the influence of the chemical solution is to be excluded) is typically a film. A pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive; the same shall apply hereinafter) and a base material that supports the pressure-sensitive adhesive are used. The pressure-sensitive adhesive is attached to an adherend and used. Such an adhesive sheet for chemical treatment (hereinafter also referred to as “chemical treatment protective sheet” or simply “protective sheet”) is, for example, glass thickness adjustment or removal of burrs formed on the cut end face of glass. Etching process that dissolves glass with chemical solution (etching solution), etching process that partially corrodes metal surface with chemical solution (etching solution), circuit board (printed circuit board, flexible printed circuit board (FPC), etc.) It can be suitably used in a plating process or the like in which the connection terminal portion is partially plated with a chemical solution (plating solution). Patent documents 1 and 2 are mentioned as literature about this kind of technique.

JP 2003-82299 A JP 2009-209233 A

  In such a situation where the protective sheet for chemical treatment is attached to the protection target portion of the adherend and immersed in the chemical solution, the protective sheet has a property of preventing the chemical solution from entering the protective target portion ( Chemical solution penetration prevention) is required. Specifically, the chemical liquid that has entered from the surface of the protective sheet for chemical liquid treatment (the surface directly exposed to the chemical liquid, that is, the surface opposite to the side attached to the adherend) permeates the protective sheet. It is necessary to prevent reaching the protected part. However, in general, chemical solutions such as an etching solution and a plating solution are often highly corrosive and / or penetrating, such as acids and alkalis. Therefore, it is not easy to sufficiently prevent such chemical solution from entering. It was. In particular, a chemical treatment protective sheet used under more severe conditions such as being exposed to a highly corrosive chemical for a long time is required to have better chemical penetration prevention.

  The present invention has been created in view of the above circumstances, and an object of the present invention is to provide a protective sheet for chemical solution treatment that is excellent in chemical solution intrusion prevention property by adopting a new configuration different from the conventional one. .

According to this invention, the protective sheet for chemical | medical solution processing provided with a base material and the adhesive layer provided in one surface of this base material is provided. The base material includes a biaxially oriented polypropylene layer. The protective sheet for chemical liquid treatment having such a configuration can exhibit excellent chemical liquid penetration prevention properties. The base material has a water vapor permeability of 5 g / m ² · day or less. The protective sheet for chemical solution treatment having such a configuration can suppress the penetration of the chemical liquid from the surface of the protective sheet (the surface directly exposed to the chemical liquid; the same applies hereinafter), and thus exhibits excellent chemical liquid penetration prevention properties. Can be.

  In a preferred embodiment of the chemical treatment protective sheet disclosed herein, the total thickness of the biaxially stretched polypropylene layer is 10 μm or more. The protective sheet for chemical solution treatment having such a configuration can exhibit better chemical solution intrusion prevention properties.

In a preferred embodiment of the chemical treatment protective sheet disclosed herein, the base material has a water vapor permeability of 0.1 g / m ² · day or more. The protective sheet for chemical treatment with such a configuration is easy to achieve both prevention of chemical penetration from the surface of the protective sheet and prevention of chemical penetration from the outer edge of the protective sheet.

  In a preferred embodiment of the chemical treatment protective sheet disclosed herein, the thickness of the substrate is 500 μm or less. The protective sheet for chemical treatment having such a configuration can be excellent in flexibility and step following ability. Improvement of the level difference following property of the protective sheet contributes to improvement in adhesion between the protective sheet and the adherend, and can further contribute to prevention of chemical penetration of the protective sheet.

  In a preferred embodiment of the chemical treatment protective sheet disclosed herein, the biaxially stretched polypropylene layer constitutes the other surface of the substrate. According to this configuration, the chemical resistance of the substrate itself is improved. The improvement of the chemical resistance of the base material can contribute to the improvement of the chemical solution intrusion prevention property.

  In a preferred embodiment of the chemical treatment protective sheet disclosed herein, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is typically an acrylic pressure-sensitive adhesive mainly composed of an acrylic polymer. The protective sheet for chemical liquid treatment having such a configuration can exhibit excellent chemical liquid intrusion prevention and high peeling workability.

  The protective sheet for chemical solution treatment disclosed herein is preferably used for applications in which a circuit board is treated with a chemical solution. Therefore, according to this specification, a circuit board on which any one of the chemical treatment protective sheets disclosed herein is attached is provided.

  The protective sheet for chemical treatment disclosed herein is preferably used for applications in which a glass substrate is treated with a chemical. Therefore, according to this specification, a glass substrate on which any one of the chemical solution protective sheets disclosed herein is attached is provided.

It is sectional drawing which shows typically the example of 1 structure of the protective sheet for chemical | medical solution processes. It is sectional drawing which shows typically the other structural example of the protective sheet for chemical | medical solution processing.

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.
In the following drawings, members / parts having the same action may be described with the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the embodiment described in the drawings is schematically illustrated in order to clearly explain the present invention, and the chemical treatment substrate for chemical treatment or the protective sheet for chemical treatment of the present invention actually provided as a product. It is not an accurate representation of size or scale.
The “sheet” in the present specification includes a film whose thickness is relatively thinner than the sheet and a tape generally referred to as an adhesive tape.

<Configuration of protective sheet for chemical treatment>
The chemical treatment protective sheet disclosed herein includes a base material and an adhesive layer provided on at least one surface of the base material. The form of the chemical treatment protective sheet may be, for example, a roll or a single plate with a separator.
A typical configuration example of such a chemical treatment protective sheet is schematically shown in FIG. The chemical treatment 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 chemical treatment protective sheet 1 has a surface on the pressure-sensitive adhesive layer 20 side of the adherend (object to be treated) before treatment with a chemical solution (a part to be protected, typically a chemical solution). (This is also referred to as “mask part” hereinafter.) This protects the mask portion from the chemical solution. Prior to use (that is, before application to an adherend), the chemical treatment protective sheet 1 typically has the surface of the pressure-sensitive adhesive layer 20 (applied surface to the adherend, hereinafter also referred to as an adhesive surface). Further, it may be in a form protected by a release liner (not shown) having at least a pressure-sensitive adhesive layer 20 side as a release surface. Alternatively, the other surface of the base material 10 (the back surface of the surface on which the pressure-sensitive adhesive layer 20 is provided) is a peeling surface, and the chemical treatment protective sheet 1 is wound in a roll shape so that the pressure-sensitive adhesive is formed on the other surface. The form which the layer 20 contact | abutted and the surface (adhesion surface) was protected may be sufficient.

<Base material>
The protective sheet for chemical treatment disclosed herein includes a base material (support base material for the pressure-sensitive adhesive layer). As a base material, the thing excellent in chemical | medical solution penetration | invasion (penetration) prevention property is preferable. In particular, as the base material, a material made of a resin material having high acid resistance can be preferably used. Such a base material is an acidic chemical solution (for example, a hydrofluoric acid solution used for glass etching, an acidic solution such as a chromium plating solution, a copper sulfate plating solution, a nickel plating solution, an acidic electroless nickel plating solution, or an acidic tin plating solution). Difficult to swell even when exposed to plating solution. This is advantageous in preventing an event that the chemical solution reaches the mask portion of the adherend by causing the acidic chemical solution to swell the base material and enter the protective sheet.

  The base material can be preferably configured as a resin film including one or two or more resin layers. The resin film is typically a non-porous resin film. The “non-porous resin film” here is a concept that is distinguished from a so-called nonwoven fabric (that is, does not include a nonwoven fabric). Such a resin film can be formed, for example, by molding a resin composition containing a resin component as a main component into a film shape.

In the technology disclosed herein, the base material has a water vapor permeability (also referred to as moisture permeability; the same shall apply hereinafter) of 5 g / m ² · day or less (more preferably 4 g / m ² · day or less, more preferably is preferably not more than 3.5g ^/ m 2 · day. protective sheet water vapor transmission rate of the base material is not more than 5g ^/ m 2 · day may show good chemical penetration preventing property.

  The water vapor permeability can be calculated by measuring the amount of water vapor that passes through a test piece of a unit area per unit time under predetermined temperature and humidity conditions. Typical test methods include a moisture sensor method, an infrared sensor method, a gas chromatograph method, and a cup method. The water vapor permeability can be measured according to JIS K 7129 or JIS Z 0208. More specifically, it is measured by the method described in the examples.

Although the lower limit of the water vapor permeability of the substrate is not particularly limited, it is preferably 0.1 g / m ² · day or more, more preferably 0.5 g / m ² · day or more, and still more preferably 1. 0 g / m ² · day or more, for example, 1.5 g / m ² · day or more. Since the protective sheet having a water vapor permeability of 0.1 g / m ² · day or more tends to improve the step following ability, the adhesion between the protective sheet and the adherend (sealability) ) Can be improved. Since the improvement in the adhesion between the protective sheet and the adherend can contribute to the prevention of the chemical solution from entering from the outer edge of the protective sheet, the chemical treatment protective sheet can easily prevent the chemical solution from entering from the surface and the outer edge.

The technology disclosed herein includes a BOPP layer made of biaxially oriented polypropylene (hereinafter also referred to as “BOPP”. “BOPP” is an abbreviation for “Biaxial Oriented Polypropylene”). By including the BOPP layer, the chemical solution penetration preventing property of the base material is improved. The inclusion of BOPP is also advantageous from the viewpoint of improving acid resistance.
Here, biaxially stretched polypropylene (BOPP) refers to a biaxially stretched film made of polypropylene (PP) as a raw material. Typically, the BOPP can be manufactured by heat-fixing the raw material PP after sequentially stretching or simultaneously stretching in two directions, the longitudinal direction and the transverse direction, to form a film.
In the technology disclosed herein, the number of BOPP layers contained in the substrate is not particularly limited, but from the viewpoint of moldability and handleability, for example, 1 to 5 (preferably 4 or less, more preferably 3 or less, It is suitable that it is typically 2 or less.

In the technology disclosed herein, PP as a raw material of the BOPP (hereinafter also simply referred to as “PP”) is propylene as a main monomer (main monomer component, that is, more than 50% by weight of the whole monomer). It can be various polymers (propylene-based polymers) as the component. The concept of propylene-based polymer here includes, for example, the following polypropylene.
A homopolymer of propylene (ie homopolypropylene). For example, isotactic polypropylene, syndiotactic polypropylene, atactic polypropylene.
A random copolymer (random polypropylene) of propylene and another α-olefin (typically, one or more selected from ethylene and an α-olefin having 4 to 10 carbon atoms). For example, random polypropylene obtained by random copolymerization of 96 mol% to 99.9 mol% of propylene and 0.1 mol% to 4 mol% of another α-olefin (preferably ethylene and / or butene).
A copolymer (block polypropylene) obtained by block copolymerizing propylene with another α-olefin (typically, one or more selected from ethylene and an α-olefin having 4 to 10 carbon atoms). Such a block polypropylene may further contain a rubber component containing at least one of propylene and the other α-olefin as a by-product. For example, a polymer obtained by block copolymerization of 0.1 mol% to 10 mol% of other α-olefin (preferably ethylene and / or butene) with 90 mol% to 99.9 mol% of propylene, and propylene and other as by-products The block polypropylene which further contains the rubber component which uses as an ingredient at least 1 sort (s) among (alpha) -olefins.

  In the technology disclosed herein, the PP may be a resin in which the main component of the resin component is a propylene-based 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 may have a composition containing at least polyethylene (PE) as the accessory component. Moreover, the composition which contains at least PE and ethylene propylene rubber (EPR) as a subcomponent may be sufficient.

  In the technology disclosed herein, the PP is a homopolypropylene, or a random copolymer of 96 mol% or more of propylene and 4 mol% or less of another α-olefin (preferably ethylene and / or butene). It is preferable that BOPP using PP as a raw material tends to have a relatively high degree of crystallinity. The high crystallinity of BOPP can advantageously contribute to improving the chemical solution intrusion preventing property of the protective sheet containing BOPP.

In the technology disclosed herein, the water vapor permeability of the BOPP layer is not particularly limited as long as the water vapor permeability of the entire base material is within the preferable range described above. Water vapor permeability of the BOPP layer is generally, 10g ^/ m 2 · day or less (more preferably 8g ^/ m 2 · day or less, more preferably 7g ^/ m 2 · day or less, typically 5 g / ^{m 2} · day or less, for example, 4 g / m ² · day or less). Since the protective sheet including the BOPP layer having a water vapor permeability of 10 g / m ² · day or less can suppress the penetration of the chemical solution mainly in the portion of the BOPP layer, it can exhibit good chemical solution penetration prevention properties.
The lower limit value of the water vapor permeability of the BOPP layer is not particularly limited, but is preferably 0.1 g / m ² · day or more, more preferably 0.5 g / m ² · day or more, and still more preferably 1. 0 g / m ² · day or more, for example, 1.5 g / m ² · day or more. Since the protective sheet containing a base material having a water vapor permeability of the BOPP layer of 0.1 g / m ² · day or more tends to improve the step following ability, adhesion between the protective sheet and the adherend is increased. (Sealability) can be improved. Since the improvement in the adhesion between the protective sheet and the adherend can contribute to the prevention of the chemical solution from entering from the outer edge of the protective sheet, the chemical treatment protective sheet can easily prevent the chemical solution from entering from the surface and the outer edge.
When the number of BOPP layers contained in the base material is 2 or more, the water vapor permeability of the BOPP layer refers to the water vapor permeability of each single BOPP layer.

  In the technique disclosed herein, the crystallinity of the BOPP is not particularly limited, but is suitably, for example, 10% or more (preferably 20% or more, more preferably 30% or more). When the crystallinity of the BOPP is equal to or higher than the lower limit value described above, the water vapor permeability of the BOPP layer tends to be low, which can contribute to the improvement of the chemical penetration prevention property of the protective sheet including the BOPP layer. As a method for measuring the crystallinity, for example, it can be calculated by measuring the heat of fusion when the sample is heated from room temperature to the melting temperature using a differential scanning calorimetry (DSC) apparatus.

  The melting point of the BOPP layer is not particularly limited, but is suitably about 130 ° C. or higher (preferably 140 ° C. or higher, more preferably 150 ° C. or higher, more preferably 160 ° C. or higher). When the melting point of the BOPP layer is increased, the chemical solution intrusion prevention property tends to be improved. The upper limit of the melting point of the BOPP layer is not particularly limited, but is usually about 200 ° C. or lower (preferably 180 ° C. or lower, more preferably 175 ° C. or lower). The melting point of the BOPP layer can be measured by, for example, a thermal analysis method using a DSC apparatus or the like.

  The tensile elastic modulus of the BOPP layer is not particularly limited, but is about 500 MPa or more (for example, 1000 MPa or more, typically 1500 MPa or more), and about 8000 MPa or less (for example, from the viewpoint of followability to the adherend surface, etc. 6000 MPa or less, typically 5000 MPa or less). The tensile elastic modulus of the BOPP layer is determined by measuring a test piece having a predetermined width along an arbitrary direction (for example, MD (Machine Direction) or TD (Transverse Direction; orthogonal to MD), preferably MD) from the BOPP layer. It can be calculated from a linear regression of the stress-strain curve obtained by cutting out and stretching the test piece in the above-mentioned one direction at room temperature (23 ° C.) in accordance with JIS K 7127.

  The tensile strength of the BOPP layer is not particularly limited, but is about 50 MPa or more (preferably 70 MPa or more, more preferably 100 MPa or more, for example 120 MPa or more), about 800 MPa or less (preferably 600 MPa or less, more preferably 500 MPa or less, For example, it is suitable that it is 400 MPa or less. When the tensile strength of the BOPP layer is equal to or higher than the lower limit value described above, handleability can be improved. If the BOPP layer has a tensile strength equal to or lower than the above-described upper limit, the step following ability tends to be improved. For the tensile strength of the BOPP layer, a test piece having a predetermined width is cut out from the BOPP layer along an arbitrary direction (for example, MD or TD, preferably MD), and the test piece is subjected to the above-mentioned in accordance with JIS Z 1712. It can be calculated from the maximum stress obtained by stretching until breaking in one direction.

  The thickness of the BOPP layer is not particularly limited, but is preferably 10 μm or more and 500 μm or less, more preferably 30 μm or more and 300 μm or less, further preferably 40 μm or more and 200 μm or less, typically 50 μm or more and 100 μm or less, for example 55 μm or more and 80 μm or less. It is. Here, when there are two or more BOPP layers, the thickness of the BOPP layer means the total thickness of the BOPP layers. The protective sheet for chemical liquid processing in which the thickness of the BOPP layer is 10 μm or more can exhibit excellent chemical liquid intrusion prevention. Further, the chemical treatment protective sheet having a BOPP layer thickness of 500 μm or less tends to improve the step following ability to the unevenness of the adherend and the adhesion to the adherend. The improvement in adhesion to the adherend can contribute to the suppression of chemical solution intrusion from the outer edge of the protective sheet.

  The base material may be a single layer or a multilayer structure having two or more layers (for example, a three-layer structure). Although it does not specifically limit, the base material which consists of a single layer (one layer) BOPP layer is mentioned as a suitable example of the base material disclosed here. As another preferred example, a substrate composed of a multilayer (for example, one to three layers) BOPP layer can be mentioned. In another aspect of the protective sheet disclosed herein, the base material may have a multilayer structure including at least one BOPP layer and at least one other layer.

  In the technology disclosed herein, when the base material has a multilayer structure, polyethylene (PE), polypropylene (PP) (excluding biaxially stretched films), ethylene propylene rubber as layers other than the BOPP layer (EPR), polyolefin resins such as ethylene-propylene-butene copolymer, ethylene-ethyl acrylate copolymer; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate; polyamide resin (PA Polyimide resin (PI); Polyphenylene sulfide resin (PPS); Polycarbonate resin (PC); Polyurethane resin (PU); Ethylene-vinyl acetate resin (EVA); Fluororesin such as polytetrafluoroethylene (PTFE); It can be employed a resin film comprising a resin component and the like; Lil resin. These resin components can be used alone or in combination of two or more.

  Any of the above-described resin films (that is, the BOPP layer and / or other layers) can contain an appropriate component depending on the use of the chemical treatment protective sheet, if necessary. For example, light stabilizers such as radical scavengers and ultraviolet absorbers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, antiblocking agents, flame retardants, etc. can do. Examples of light stabilizers include those containing benzotriazoles, hindered amines, benzoates and the like as active ingredients. Examples of the antioxidant include those containing alkylphenols, alkylene bisphenols, thiopropylene acid esters, organic phosphite esters, amines, hydroquinones, hydroxylamines and the like as active ingredients. Each of these additives can be used alone or in combination of two or more. The amount of the additive should be the same as the usual amount of the resin film used as the base material of the protective sheet in the application depending on the use of the protective sheet (for example, for glass etching and plating masking). Can do.

  The surface of the substrate on which the pressure-sensitive adhesive layer is provided (the pressure-sensitive adhesive layer-side surface, the surface to which the pressure-sensitive adhesive is applied) is treated to improve the adhesion to the pressure-sensitive adhesive layer (of the pressure-sensitive adhesive). Treatment for obtaining anchoring properties), for example, corona discharge treatment, acid treatment, ultraviolet irradiation treatment, plasma treatment, surface treatment such as primer coating (primer) coating may be performed. As the surface treatment (primer treatment) by primer application, it is preferable to use an undercoat agent in which an isocyanate is blended with an acrylic polymer. The surface (back surface) opposite to the pressure-sensitive adhesive layer side surface of the base material may be subjected to surface treatment such as antistatic treatment or peeling treatment, if necessary. As the release treatment, for example, by providing a long-chain alkyl-based or silicone-based release treatment layer on the back surface of the base material, the unwinding force of the protective sheet wound in a roll shape can be reduced.

The thickness of the base material disclosed herein is not particularly limited as long as the preferable water vapor permeability described above can be realized, and may be, for example, 10 μm or more (typically 30 μm or more). In general, the thickness of the base material is suitably 40 μm or more, preferably 50 μm or more, and more preferably 55 μm or more from the viewpoint of chemical solution penetration prevention. When the thickness of the base material is increased, it tends to be easy to prevent the chemical solution from entering from the surface of the protective sheet. In general, the thickness of the base material is 500 μm or less (preferably 300 μm or less, more preferably 200 μm or less, typically 100 μm or less, for example, 80 μm or less) from the viewpoint of followability and adhesion to a stepped surface. It is.
In addition, the said level | step difference may originate in the structure formed in the surface of the to-be-adhered body. As an adherend having such a structure, for example, a transparent conductive film (for example, ITO (indium tin oxide) is partially formed on the surface, such as used in tablet computers, mobile phones, and organic LEDs (light emitting diodes). ) Film) or a glass substrate provided with FPC.

  In the technique disclosed herein, the thickness of the BOPP layer is 10% or more (more preferably 20% or more, more preferably 30% or more, such as 40% or more, typically, the thickness of the substrate). 50% or more). According to the base material having such a configuration, it is possible to efficiently prevent the penetration of the chemical liquid by suppressing the thickness of the whole base material.

The base material disclosed here includes the BOPP layer, and the pressure-sensitive adhesive layer is disposed on one surface of the base material. In a preferred embodiment of the protective sheet disclosed herein, at least the other surface of the substrate (that is, the surface of the substrate that is not the pressure-sensitive adhesive layer side) is constituted by a BOPP layer. As a typical example of such a configuration, (a) an embodiment in which the entire base material is composed of a BOPP layer (one layer or two or more layers), (b) a BOPP layer constituting the other surface of the base material, The aspect containing layers other than BOPP laminated | stacked on the back surface is illustrated.
An example of the configuration of the protective sheet for chemical treatment according to the preferred embodiment (b) described above is schematically shown in FIG. The chemical treatment protective sheet 2 includes a base material 10 and a pressure-sensitive adhesive layer 20 provided on one surface thereof. The base material 10 has a two-layer laminated structure composed of a layer 10a constituting the surface and a layer 10b constituting the back surface. In the technology disclosed herein, the layer 10a constituting the surface of the substrate 10 may be the BOPP layer. The protective sheet 2 for chemical treatment is used by sticking the surface on the pressure-sensitive adhesive layer 20 side to an adherend. Since the protective sheet 2 for chemical treatment having such a structure is protected by a BOPP layer having high chemical resistance (typically acid resistance) on the front side (side exposed to the chemical liquid) of the protective sheet, The deterioration of the base material itself can be suppressed. Such a protective sheet for chemical solution treatment can exhibit high chemical solution penetration prevention even when used under more severe conditions such as chemical treatment for a long time.

<Adhesive layer>
In the technology disclosed herein, the type of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer provided on the substrate is not particularly limited. For example, acrylic pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive (natural rubber-based, synthetic rubber-based, mixed system thereof), silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, polyether-based pressure-sensitive adhesive, fluorine-based pressure-sensitive adhesive, polyester-based 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 adhesives, rubber adhesives, and silicone adhesives are preferred because they are excellent in resistance to chemicals (for example, acidic chemicals such as etching solutions and acidic plating solutions). Similarly, the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive is not particularly limited, and a composition in which the polymer constituting the pressure-sensitive adhesive described above is blended and the blending ratio is appropriately selected can be used.

  Especially, it is preferable that the adhesive which comprises an adhesive layer is an acrylic adhesive containing an acrylic polymer as a base polymer (The main component in a polymer component, main adhesive component). Here, the “base polymer” refers to a main component (main adhesive component) among the polymer components contained in the adhesive, and typically refers to a component occupying more than 50% by weight of the polymer component. The “acrylic polymer” refers to a polymer including a monomer unit derived from a monomer (acrylic monomer) having at least one (meth) acryloyl group in one molecule. The acrylic polymer includes an acrylic monomer, and a monomer raw material (a single monomer or a monomer that may further include another monomer copolymerizable with the acrylic monomer (that is, a monomer having no (meth) acryloyl group)) It may be a polymer (copolymer) synthesized by polymerizing a monomer mixture.

A typical example of the acrylic polymer is one in which the main component of the acrylic monomer contained in the monomer raw material is an alkyl (meth) acrylate. “(Meth) acrylate” means acrylate and methacrylate comprehensively. Similarly, “(meth) acryloyl” refers to acryloyl and methacryloyl, and “(meth) acryl” refers to acryl and methacryl generically.
The proportion of the alkyl (meth) acrylate in the acrylic monomer contained in the monomer raw material is typically more than 50% by weight, preferably 60% by weight or more, more preferably 70% by weight or more. For example, 80 weight. In a preferred embodiment, the proportion of alkyl (meth) acrylate in the acrylic monomer may be 90% by weight. A monomer raw material having a composition containing only alkyl (meth) acrylate as the acrylic monomer may be used. Alternatively, the monomer raw material may contain an acrylic monomer other than alkyl (meth) acrylate, for example, for the purpose of adjusting the adhesion performance or gel fraction. In that case, the ratio of the alkyl (meth) acrylate to the acrylic monomer in the monomer raw material can be, for example, 99.5% by weight or less, and may be 99% by weight or less (for example, 98% by weight or less). .

As the alkyl (meth) acrylate, for example, a compound represented by the following formula (1) can be preferably used.
CH ₂ = CR ¹ COOR ² (1)
Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group. R ² is a linear or branched alkyl group, typically a C _1-20 alkyl group. From the viewpoint of the storage elastic modulus of the pressure-sensitive adhesive, an alkyl (meth) acrylate in which R ² is a C _1-14 (eg, C _1-10 ) alkyl group can be preferably used.
In this specification, C _ab refers to a range of the number of carbon atoms (a or more and b or less). For example, a C _1-20 alkyl group refers to an alkyl group having 1 to 20 carbon atoms.

Examples of the alkyl (meth) acrylate in which R ² is a C _1-14 chain alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl. (Meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (Meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate and the like can be mentioned. These alkyl (meth) acrylates 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).

  Monomers (other monomers) other than those described above may be copolymerized in the acrylic polymer in the technology disclosed herein within a range that does not significantly impair the effects of the present invention. The other monomers can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer, adjusting the adhesion performance, and the like. Examples of monomers that can improve the cohesive strength and heat resistance of the pressure-sensitive adhesive include sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl esters, and aromatic vinyl compounds. Preferred examples of these include vinyl esters. Specific examples of vinyl esters include vinyl acetate (VAc), vinyl propionate, vinyl laurate, and the like. Of these, VAc is preferable.

  Other monomers that can introduce a functional group that can serve as a cross-linking point to an acrylic polymer or contribute to an improvement in adhesive strength include a hydroxyl group (OH group) -containing monomer, a carboxy group-containing monomer, an acid anhydride group-containing monomer, an amide Examples thereof include a group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, an epoxy group-containing monomer, (meth) acryloylmorpholine, and vinyl ethers.

  As a preferable example of the acrylic polymer in the technology disclosed herein, an acrylic polymer obtained by copolymerizing a carboxy group-containing monomer as the other monomer may be mentioned. Examples of carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Is done. Especially, AA and MAA are mentioned as a preferable carboxy group containing monomer.

  Another preferred example of the acrylic polymer in the technology disclosed herein is an acrylic polymer in which a hydroxyl group-containing monomer is copolymerized as the other monomer. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meta ) Hydroxyalkyl (meth) acrylates such as acrylate; polypropylene glycol mono (meth) acrylate; N-hydroxyethyl (meth) acrylamide and the like. Of these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) are more preferable.

The “other monomers” may be used alone or in combination of two or more. The total content of other monomers is not particularly limited. For example, it can be about 40% by weight or less (typically 0.001 to 40% by weight) of the total monomer components, and usually about 30% by weight or less (typically 0.01 to 30% by weight). For example, 0.1 to 10% by weight).
Although not particularly limited, when a carboxy group-containing monomer is used as the other monomer, the content thereof is about 0.1 to 10% by weight (for example, 0.2 to 8% by weight, typically, Is suitably 0.5 to 5% by weight).
Although not particularly limited, when a hydroxyl group-containing monomer is used as the other monomer, the content thereof is about 0.001 to 10% by weight (for example, 0.01 to 8% by weight, typically, 0.02 to 5% by weight) is appropriate.

  Although not particularly limited, the copolymer composition of the acrylic polymer is such that the Tg of the acrylic polymer is, for example, -20 ° C or lower (preferably -30 ° C or lower, preferably -40 ° C or lower, more preferably -50 ° C. The following can be set. When the Tg of the acrylic polymer is not too high, good adhesion to the surface of the adherend is exhibited, and the penetration of the chemical solution from the interface between the pressure-sensitive adhesive and the adherend can be effectively prevented. The lower limit of the Tg of the acrylic polymer is not particularly limited, but it is usually appropriate to set it to −70 ° C. or higher.

Here, the Tg of the acrylic polymer refers to a fox based on the Tg of the homopolymer (homopolymer) of each monomer constituting the polymer and the weight fraction (copolymerization ratio based on weight) of the monomer. The value obtained from the formula. Accordingly, the Tg of the acrylic polymer can be adjusted by appropriately changing the composition of the monomer raw material (that is, the type of monomer used and the ratio of the amount used). As the Tg of the homopolymer, the value described in known materials is adopted.
In the technique disclosed here, the following values are specifically used as the Tg of the homopolymer.
2-Ethylhexyl acrylate -70 ° C
n-Butyl acrylate -55 ° C
Ethyl acrylate -22 ° C
Methyl acrylate 8 ℃
Methyl methacrylate 105 ° C
Cyclohexyl methacrylate 66 ° C
Vinyl acetate 32 ° C
2-hydroxyethyl acrylate -15 ° C
Styrene 100 ° C
Acrylic acid 106 ℃
Methacrylic acid 130 ° C
For the Tg of homopolymers other than those exemplified above, the values described in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc, 1989) shall be used.
When not described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc, 1989), values obtained by the following measurement method are used (Japanese Patent Laid-Open No. 2007-51271). reference).
Specifically, a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser is charged with 100 parts by weight of monomer, 0.2 part by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization solvent. Stir for 1 hour while flowing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63 ° C. and the reaction is carried out for 10 hours. Next, the mixture is cooled to room temperature to obtain a homopolymer solution having a solid concentration of 33% by weight. Subsequently, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-like homopolymer) having a thickness of about 2 mm. This test sample was punched into a disk shape having a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to shear strain at a frequency of 1 Hz using a viscoelasticity tester (ARES, manufactured by Rheometrics), in a temperature range of −70 to 150 ° C. The viscoelasticity is measured by the shear mode at a heating rate of 5 ° C./min, and the peak top temperature of tan δ is defined as Tg of the homopolymer.

  A method for polymerizing the monomer or a mixture thereof (monomer raw material) is not particularly limited, and a conventionally known general polymerization method can be employed. Examples of such a polymerization method include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. Among these, solution polymerization is preferable because it is excellent in water resistance and chemical solution penetration prevention.

  When solution polymerization is employed as the polymerization method for the acrylic polymer, examples of the polymerization solvent include aromatic compounds such as toluene and xylene (typically aromatic hydrocarbons); acetates such as ethyl acetate and butyl acetate. Any one selected from aliphatic or alicyclic hydrocarbons such as hexane, cyclohexane and methylcyclohexane; halogenated alkanes such as 1,2-dichloroethane; ketones such as methyl ethyl ketone and acetylacetone; A solvent or 2 or more types of mixed solvents can be used.

  Although it does not specifically limit as a polymerization initiator, For example, the redox type | system | group which combined oxidizing agents and reducing agents, such as an azo initiator, a peroxide initiator, a substituted ethane initiator, and a peroxide. An initiator etc. are illustrated. For example, one or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile can be preferably used.

  The amount of the polymerization initiator used can be appropriately selected according to the type of polymerization initiator and the type of monomer (composition of the monomer mixture), but is usually 0.005 parts by weight or more with respect to 100 parts by weight of the monomer raw material. It is appropriate to select from the range of 1 part by weight or less. As a method for supplying the polymerization initiator, any of a batch charging method, a continuous supply method, a divided supply method, etc. in which substantially the entire amount of the polymerization initiator to be used is put in the reaction vessel before the supply of the monomer mixture is started. It is. From the viewpoint of ease of polymerization operation, ease of process control, etc., for example, a batch charging method can be preferably employed. The polymerization temperature can be, for example, about 20 ° C. to 100 ° C. (typically 40 ° C. to 90 ° C.).

  For the above polymerization, various conventionally known chain transfer agents (which may be grasped as molecular weight regulators or polymerization degree regulators) can be used as necessary. Such chain transfer agents are selected from mercaptans such as dodecyl mercaptan (dodecanethiol), glycidyl mercaptan, 2-mercaptoethanol, mercaptoacetic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, and the like. There may be one or more. When the chain transfer agent is used, the amount used is not particularly limited, but for example, it can be about 0.001 to 10 parts by weight with respect to 100 parts by weight of the monomer raw material. Alternatively, a chain transfer agent need not be used. As a preferred embodiment, an embodiment in which the monomer raw material is polymerized by solution polymerization without using a chain transfer agent is exemplified.

The weight average molecular weight (Mw) of the acrylic polymer is not particularly limited, but usually about 10 × 10 ⁴ or more and 200 × 10 ⁴ or less is appropriate. When solution polymerization is used as the polymerization method, the weight average molecular weight of the acrylic polymer is suitably about 30 × 10 ⁴ or more and 150 × 10 ⁴ or less from the viewpoint of solution viscosity, adhesive performance, etc., and 40 × 10 ⁴ or more. About 100 × 10 ⁴ or less is preferable. When the Mw of the acrylic polymer is within the above range, both good wettability to the adherend surface and cohesive force of the adhesive layer are compatible, and effective entry of chemicals from the interface between the adhesive and adherend is effective. Can be prevented. Here, Mw refers to a standard polystyrene equivalent value obtained by GPC (gel permeation chromatography).

  The pressure-sensitive adhesive layer of the protective sheet disclosed herein may be formed using a pressure-sensitive adhesive composition containing an acrylic polymer as described above. For example, the pressure-sensitive adhesive composition may be prepared by subjecting a polymerization reaction liquid obtained by polymerizing a monomer raw material (typically solution polymerization) to an appropriate treatment such as concentration adjustment or pH adjustment as necessary, or acrylic. It can be prepared by appropriately blending a pressure-sensitive adhesive forming component (polymer, tackifier, etc.), an additive (for example, a crosslinking agent) and the like other than the polymer.

  The form of the pressure-sensitive adhesive composition is not particularly limited. For example, various forms such as a solvent type, an aqueous emulsion type, an aqueous solution type, an active energy ray (for example, ultraviolet ray) curable type, and a hot melt type may be used. Among these, a solvent-type pressure-sensitive adhesive composition is particularly preferable from the viewpoint of resistance to an aqueous chemical solution (prevention of chemical solution penetration). Such a solvent-type pressure-sensitive adhesive composition is typically prepared in the form of a solution containing the acrylic polymer in an organic solvent. As said organic solvent, the thing similar to the polymerization solvent used for solution polymerization can be used. Although not particularly limited, from the viewpoints of drying efficiency and coating properties of the pressure-sensitive adhesive composition, the solvent-type pressure-sensitive adhesive composition is usually treated with a solid content (NV) of 10% by weight to 55% by weight (for example, It is appropriate to prepare it at 15 wt% or more and 45 wt% or less.

  It is preferable that the said adhesive composition contains a crosslinking agent. The type of the crosslinking agent is not particularly limited, and may be appropriately selected from various crosslinking agents usually used in the pressure-sensitive adhesive field according to, for example, the type of the crosslinkable functional group of the functional group-containing monomer. Can do. Examples of various crosslinking agents usually used in the pressure-sensitive adhesive field include isocyanate crosslinking agents such as polyisocyanates, silane crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and metal chelate crosslinking agents. And melamine-based crosslinking agents. Such a crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

  Examples of the isocyanate-based crosslinking agent include: aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; More specifically: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4-tolylene diisocyanate, 4 Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene Diisocyanate trimer adduct (made by Nippon Polyurethane Industry Co., Ltd., trade name “Coronate HL”), isocyanurate of hexamethylene diisocyanate (Nippon Polyureta) It can be exemplified, and the like; Kogyo Co., Ltd. under the trade name "Coronate HX") isocyanate adducts such as. As an isocyanate type crosslinking agent, 1 type of such an isocyanate compound can be used individually or in combination of 2 or more types.

  Examples of the epoxy-based crosslinking agent include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (manufactured by Mitsubishi Gas Chemical Company, trade name “TETRAD-X”), 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (trade name “TETRAD-C” manufactured by Mitsubishi Gas Chemical Company) and the like. Examples of the melamine-based crosslinking agent include hexamethylol melamine.

  Especially, use of an isocyanate type crosslinking agent and / or an epoxy type crosslinking agent is preferable from a viewpoint of cohesion force improvement. The use of an isocyanate-based cross-linking agent is more preferable from the viewpoint of achieving a high degree of compatibility between chemical solution penetration prevention and peeling workability. The amount of the crosslinking agent used is not particularly limited, and is, for example, about 10 parts by weight or less (for example, about 0.01 part by weight or more and 10 parts by weight or less, preferably about 100 parts by weight of the base polymer (preferably acrylic polymer). 0.1 to 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 part by weight or more and 0.5 part by weight or less (preferably 0.001 part by weight or more and 0.001 part by weight or more) with respect to 100 parts by weight of the acrylic polymer. 1 part by weight or less).

  Moreover, in order to achieve both the sealing performance during chemical treatment and the peelability after chemical treatment, an adhesive composition in which the adhesive strength of the adhesive is subsequently reduced by radiation, heat, etc., after a protective sheet is applied. It may be used. 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.

  As a method for providing the pressure-sensitive adhesive layer on the substrate, for example, a method (direct method) in which the above-mentioned pressure-sensitive adhesive composition is directly applied (typically applied) to the substrate and cured, or an appropriate release surface ( For example, the pressure-sensitive adhesive composition is applied on the surface of a transfer sheet having peelability and cured to form a pressure-sensitive adhesive layer on the release surface, and the pressure-sensitive adhesive layer is bonded to a substrate. And a transfer method (transfer method) can be used. The curing treatment may be one or more treatments selected from drying (heating), cooling, crosslinking, additional copolymerization reaction, aging and the like. For example, a treatment simply drying a pressure-sensitive adhesive composition containing a solvent (heating treatment, etc.) or a treatment simply cooling (solidifying) a pressure-sensitive adhesive composition in a heated and melted state is also referred to as a curing treatment here. May be included. When the said hardening process includes two or more processes (for example, drying and bridge | crosslinking), these processes may be performed simultaneously and may be performed over multiple steps.

  Application of the pressure-sensitive adhesive composition can be carried out using a conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray 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 by holding at about 40 ° C. to 60 ° C. so that the crosslinking reaction further proceeds. The aging time may be appropriately selected according to the desired degree of crosslinking and the progress rate of the crosslinking reaction, and can be, for example, about 12 hours to 120 hours, typically about 12 hours to 72 hours.

  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, 1 μm or more and 100 μm or less. From the viewpoint of adhesion to the adherend surface, the preferred thickness is 5 μm or more, more preferably 7 μm or more (for example, 10 μm or more, typically 15 μm or more). Further, from the viewpoint of peeling workability, the thickness of the pressure-sensitive adhesive layer is preferably 70 μm or less, and typically 50 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 intrusion of the chemical liquid due to the swelling of the pressure-sensitive adhesive.

The gel fraction of the adhesive which comprises a protective sheet is not specifically limited, For example, it may be 20 weight% or more. From the viewpoint of improving the peeling workability (suppressing high-speed peeling strength) and the like, the gel fraction is usually preferably 25% by weight or more. Increased gel fraction of the adhesive improves the prevention of chemical penetration from the outer edge of the protective sheet (typically, the ability to prevent chemical penetration due to the adhesive mainly swelling with the chemical) To do. 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. From these viewpoints, the gel fraction of the pressure-sensitive adhesive is more preferably 27% by weight or more (for example, 30% by weight or more).
The upper limit of the gel fraction is not particularly limited, but is typically 98% by weight or less, preferably 95% by weight or less, more preferably less than 93% by weight (for example, 91% by weight or less). 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 technique disclosed herein can also be preferably implemented in an embodiment in which the gel fraction of the pressure-sensitive adhesive is 95% by weight or less (typically 93% by weight or less) from the viewpoint of adhesion.
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. In addition, the measurement of a gel fraction can be performed according to the method as described in the Example mentioned later.

  The protective sheet for chemical treatment disclosed herein 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 the adherend). . The release liner is not particularly limited. For example, a release liner having a release treatment layer on the surface of a liner substrate such as a plastic film or paper, a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin resin (polyethylene, polypropylene, etc.) And a release liner made of a low adhesion material. The release treatment layer may be formed by surface-treating the liner base material with various release treatment agents such as silicone-based, long-chain alkyl-based, fluorine-based, and molybdenum sulfide. The thickness of the release liner is not particularly limited, and may be about 5 μm to 500 μm (for example, about 10 μm to 200 μm, typically about 30 μm to 200 μm).

  In a preferred embodiment disclosed herein, the protective sheet has a change in pH of the sealed pH test paper of 1 in 12 hours after being immersed in a 20 wt% hydrofluoric acid aqueous solution in the evaluation of chemical solution intrusion prevention. Can be less. The protective sheet satisfying this characteristic can sufficiently prevent the chemical solution from entering the portion to be protected. In the evaluation test, it is more preferable that the color (pH) of the pH test paper does not substantially change after 12 hours from being immersed in a 20% by weight hydrofluoric acid aqueous solution. Specifically, the evaluation of the chemical solution intrusion prevention property is measured by the method described in Examples described later.

  The protective sheet for chemical liquid treatment disclosed herein is excellent in performance of effectively suppressing the chemical liquid (typically an acidic chemical liquid) from passing through the protective sheet. As a result, it is possible to reliably prevent the chemical solution from entering a region not intended to be exposed to the chemical solution and protect the surface. Taking advantage of such features, the chemical treatment protective sheet disclosed herein is a glass for reducing the thickness of the glass or removing burrs and microcracks formed on the cut end surface of the glass, for example. Etching process that dissolves metal with chemical solution (etching solution), etching process that partially corrodes metal surface with chemical solution (etching solution) for decoration and printability, circuit board (printed circuit board, flexible printed circuit board (FPC)) Etc.) can be suitably used in a plating process or the like in which a connection terminal portion or the like is partially plated with a chemical solution (plating solution).

  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.

The protective sheet for chemical | medical solution processing which concerns on Examples 1-Example 4 was created as follows.
<Example 1>
[Base material]
A BOPP film (manufactured by Santox, product name “PA30”, thickness 60 μm) having corona discharge treatment on both sides was prepared (base material a).

[Adjustment of adhesive composition]
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, toluene as a polymerization solvent, 100 parts of 2-ethylhexyl acrylate and 4 parts of 2-hydroxyethyl acrylate as a monomer raw material, and 2, as an azo polymerization initiator 0.2 part of 2′-azobis (2-methylpropionitrile) (manufactured by Wako Pure Chemical Industries, Ltd., product name “AIBN”) was added, and polymerization was performed in ethyl acetate to obtain an acrylic polymer solution. The acrylic polymer had a Tg of −68 ° C. and Mw of 550,000 calculated from the Fox equation. An isocyanate-based crosslinking agent ("Coronate (registered trademark) L" manufactured by Nippon Polyurethane Industry Co., Ltd., trimethylolpropane / tolylene diisocyanate trimer) as a crosslinking agent with respect to 100 parts of the solid content of the acrylic polymer solution thus obtained. 2.67 parts of adduct solid content 75 wt% ethyl acetate solution), 0.02 part of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., product name “Environizer OL-1”) as a crosslinking accelerator, Furthermore, in order to adjust solid content, toluene was added and the adhesive composition was obtained.

[Preparation of protective sheet]
The pressure-sensitive adhesive composition was applied to one side of the substrate a and dried at 80 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of about 20 μm. A silicone-treated surface of a polyethylene terephthalate film (Mitsubishi Chemical Polyester Film Co., Ltd., “Diafoil (registered trademark) MRF38”) having a thickness of 38 μm treated on one side with a silicone-based release agent was bonded to this adhesive layer. The protective sheet for chemical treatment according to Example 1 was obtained by aging at 4 ° C. for 4 days. The gel fraction of the pressure-sensitive adhesive according to Example 1 measured by the method described below was 90%.

[Gel fraction measurement]
About 0.1 g of the adhesive collected from the protective sheet for chemical treatment after aging was added to a porous sheet made of tetrafluoroethylene resin (trade name “Nitoflon (registered trademark) NTF1122” manufactured by Nitto Denko Corporation) with a total weight Wa. The yarn was wrapped in a drawstring shape, and the total weight Wb of this wrap was weighed. The package was immersed in a solvent (ethyl acetate) and allowed to stand at 23 ° C. for 7 days, and then dried at 120 ° C. for 2 hours. The weight Wc of the package after drying was measured. The above-mentioned Wa, Wb and Wc were substituted into the following formula to calculate the gel fraction of the pressure-sensitive adhesive.
Gel fraction [%] = (Wc−Wa) / (Wb−Wa) × 100

<Example 2>
The chemical solution treatment according to Example 2 was carried out in the same manner as in Example 1 except that a BOPP film (product name “FOS-BT”, thickness 60 μm, manufactured by Futamura Chemical Co., Ltd.) with both sides subjected to corona discharge treatment as a substrate was used. A protective sheet was prepared.

<Example 3>
Two BOPP films (product name “FOP-K”, thickness 50 μm, manufactured by Futamura Chemical Co., Ltd.) having corona discharge treatment on both sides were prepared. A laminated substrate having a thickness of 100 μm was prepared by laminating the second BOPP film on one side of the first BOPP film by a dry laminating method. A protective sheet for chemical solution treatment according to Example 3 was produced in the same manner as in Example 1 except that the above-mentioned laminated substrate was used instead of the substrate a.

<Example 4>
In this example, an unstretched polypropylene (CPP) film (manufactured by Mitsui Chemicals, Inc., product name “RXC22”, thickness 100 μm) having a corona discharge treatment on one side was used as the base material. A protective sheet for chemical treatment according to Example 4 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition was applied to the corona-treated surface of this substrate.

[Measurement of weight average molecular weight of acrylic polymer]
The weight average molecular weight of the acrylic polymer was measured using a GPC device (device name: HLC-8220 GPC, manufactured by Tosoh Corporation). The measurement conditions were as follows, and the molecular weight was determined by standard polystyrene conversion.
Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)
Sample injection volume: 10 μl
・ Eluent: THF
・ Flow rate: 0.6ml / min
・ Measurement temperature: 40 ℃
·column:
Sample column: TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1 piece)
・ Detector: Differential refractometer (RI)

[Water vapor permeability]
The water vapor transmission rate of the measurement sample was measured according to a moisture permeability test (cup method) defined in JIS Z 0208. That is, the measurement sample was cut into a diameter of 70 mm and set in a moisture permeable cup (No. 318 moisture permeable cup manufactured by Yasuda Seisakusho Co., Ltd.) containing an appropriate amount of calcium chloride. This was put into a thermostat of 40 ° C. and 90% RH, and the water vapor permeability (g / m ² · 24 hours) was determined by measuring the weight increase of the moisture permeable cup containing calcium chloride every 24 hours. The results are shown in Table 1.

[Evaluation of chemical penetration prevention]
The protective sheet according to each example was cut into a size of 80 mm × 30 mm. Further, a glass substrate manufactured by Matsunami Glass Industry Co., Ltd. and a trade name “MICROSLIDE GLASS” (length 76 mm, width 26 mm, thickness 1.3 mm) were prepared. A pH test paper (product name “Universal indicator paper pH 1-11” manufactured by Macherey-Nagel, Inc.) cut to a size of 5 mm × 5 mm is placed in the center of the non-tin surface of the glass substrate, and the cut protective sheet is placed thereon. Were stacked so that the pH test paper was in the center, and the hand roller was reciprocated once and pasted. In this way, the pH test paper was sealed with the protective sheet to prepare a sample for evaluation. The sample was allowed to stand for 30 minutes, and then immersed in 100 mL of a 20 wt% hydrofluoric acid aqueous solution stored in a plastic container (length 100 mm × width 100 mm × depth 30 mm). The color change (pH change) of the pH test paper after a predetermined time (6 hours or 24 hours) after the immersion was visually confirmed, and the pH was recorded. The confirmation was performed after taking out the sample for evaluation from the aqueous hydrofluoric acid solution using polyethylene tweezers, washing it thoroughly with water, and drying it at 50 ° C. for 2 hours. The results are shown in Table 1.

As shown in Table 1, the chemical treatment protective sheet according to Examples 1 to 3 using a base material including a BOPP layer and having a water vapor permeability of 5 g / m ² · day or less is a 20 wt% hydrofluoric acid aqueous solution. Even after soaking for 24 hours, the color of the pH test paper, which is the protection target of the protective sheet, did not change, and it was revealed that it has a high chemical solution penetration preventing property. On the other hand, in the protective sheet for chemical treatment according to Example 4, the color of the pH test paper has already changed to a color indicating pH 4 after 6 hours of immersion in the hydrofluoric acid aqueous solution, and further, pH 3 is adjusted after immersion for 24 hours. The color shown was changed. From this, it was found that the chemical treatment protective sheet according to Example 4 has low chemical penetration prevention property for a long-time chemical treatment.

  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, chemical protection sheet (protection sheet)
DESCRIPTION OF SYMBOLS 10 Base material 10a The layer which comprises the surface 10b The layer which comprises the back surface 20 Adhesive layer

Claims (8)

A protective sheet for chemical treatment comprising a substrate and an adhesive layer provided on one surface of the substrate,
The substrate includes a biaxially oriented polypropylene layer,
The said base material is a protective sheet for chemical | medical solution processing whose water vapor permeability is 5 g / m < ² > * day or less.   The total thickness of the said biaxially-stretched polypropylene layer is a protective sheet for chemical | medical solution processing of Claim 1 which is 10 micrometers or more. The said base material is a protective sheet for chemical | medical solution processing of Claim 1 or 2 whose water vapor permeability is 0.1 g / m < ² > * day or more.   The protective sheet for chemical | medical solution processing as described in any one of Claim 1 to 3 whose thickness of the said base material is 500 micrometers or less.   The protective layer for chemical | medical solution processing as described in any one of Claim 1 to 4 whose layer which comprises the other surface of the said base material is the said biaxially-stretched polypropylene layer.   The adhesive which comprises the said adhesive layer is a protective sheet for chemical | medical solution treatment as described in any one of Claim 1 to 5 which is an acrylic adhesive which has an acrylic polymer as a main component.   A circuit board to which the protective sheet for chemical treatment according to any one of claims 1 to 6 is attached.   A glass substrate on which the protective sheet for chemical treatment according to any one of claims 1 to 6 is attached.

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