Pressure sensitive adhesive sheet

Abstract

To provide a pressure sensitive adhesive sheet having excellent adhesiveness, alkali resistance and mechanical characteristics as a surface protection sheet to be adhered on a surface when applying a chemical treatment using a chemical solution to glass, etc.SOLUTION: A pressure sensitive adhesive sheet includes a substrate layer and an adhesive layer disposed on one side of the substrate layer. In the pressure sensitive adhesive sheet, a mass loss is 3% or less after immersing for 180 mins in a NaOH solution of 50 wt.% at 125°C. In the pressure sensitive adhesive sheet, a total thickness decrease amount is 3 μm or less and a contraction coefficient is within ±5%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet, and more particularly to a pressure-sensitive adhesive sheet having excellent adhesiveness, alkali resistance and mechanical properties. [Background technology]

[0002] When processing various articles, a technique of protecting the surface by attaching a protective sheet (adhesive sheet) to the surface is known to prevent damage (scratches, stains, corrosion, etc.). For example, when chemical treatment is performed on glass or the like using a chemical solution (alkaline etching solution), the surface is protected by attaching an adhesive sheet to the surface of the object to be protected. However, in such applications, it is difficult for adhesive sheets to achieve both adhesion, alkali resistance, and mechanical properties. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide an adhesive sheet that has excellent adhesion, alkali resistance, and mechanical properties even after etching. [Means for solving the problem]

[0004] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that the above-mentioned problems can be solved by controlling the mass loss, total thickness reduction, and shrinkage rate after immersing an adhesive sheet in a 50 wt % NaOH solution at 125°C for 180 minutes within specific ranges, and thus completed the present invention.

[0005] That is, the present invention is as follows. [1] An adhesive sheet having a base layer and an adhesive layer provided on one side of the base layer, wherein after immersion in a 50 wt% NaOH solution at 125°C for 180 minutes, the adhesive sheet experiences a mass loss of 3% or less, a reduction in the overall thickness of the adhesive sheet is 3 μm or less, and a shrinkage rate is within ±5%. [2] The pressure-sensitive adhesive sheet according to [1], wherein, after the pressure-sensitive adhesive sheet is attached to glass and then immersed in a 50 wt% NaOH solution at 125°C for 180 minutes, the edge erosion rate is 2% or less, or the edge erosion amount is 2mm or less, and the peel force when the pressure-sensitive adhesive sheet is peeled from the glass at a pulling rate of 300mm / min in a 180° direction at 23°C is 12N / 20mm or less. [3] The pressure-sensitive adhesive sheet according to [1] or [2], wherein the peel strength when the pressure-sensitive adhesive sheet is attached to glass and then peeled from the glass at a pulling rate of 300 mm / min in a 180° direction at 23°C is 0.5 N / 20 mm or more. [4] The pressure-sensitive adhesive sheet according to [1] or [2], wherein the substrate layer is a monolayer film formed from one or more of polyolefins or fluorinated polyolefins, or a composite film combining two or more of the monolayer films, and the thickness of the substrate layer is 5 to 100 μm. [5] The pressure-sensitive adhesive sheet according to [4], wherein the polyolefin is at least one selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP), and the fluorinated polyolefin is at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). [6] The pressure-sensitive adhesive sheet according to [1] or [2], wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition comprising 100 parts by weight of a rubber elastomer, 5 to 50 parts by weight of a functional resin, 0.5 to 5 parts by weight of a cross-linking agent, and 0.2 to 2 parts by weight of a release aid, and the pressure-sensitive adhesive layer has a thickness of 1 to 40 μm. [7] The pressure-sensitive adhesive sheet according to [6], wherein the rubber elastomer is at least one saturated rubber elastomer selected from saturated ethylene propylene rubber, silicone rubber, fluororubber, and thermoplastic styrene butadiene rubber (SEBS), and the Shore hardness of the rubber elastomer is 30 to 100. [8] The pressure-sensitive adhesive sheet according to [6], wherein the functional resin is at least one selected from epoxy resins, furan resins, silicone resins, urethane resins, terpene resins, and petroleum resins. [9] The pressure-sensitive adhesive sheet according to [8], wherein the acid value of the functional resin is 5 mg KOH / g or less.

[10] The pressure-sensitive adhesive sheet according to [1] or [2], further comprising an undercoat layer, the undercoat layer being provided between the base layer and the pressure-sensitive adhesive layer, and the undercoat layer having a thickness of 0.05 to 1 μm.

[11] A glass etching method comprising: attaching the adhesive sheet according to any one of [1] to

[10] to one or more main surfaces of glass; bringing the one or more main surfaces of the glass into contact with an etching solution; and then peeling off the adhesive sheet.

[12] The glass etching method according to

[11] , wherein the temperature of the etching solution is 100 to 130°C, and the time for which one or more main surfaces of the glass are brought into contact with the etching solution is 60 to 200 minutes. [Effects of the Invention]

[0006] When the pressure-sensitive adhesive sheet of the present invention is stuck to glass, for example, it retains excellent adhesiveness, alkali resistance and mechanical properties even after being etched with an alkaline etching solution. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view that schematically illustrates the structure of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Preferred embodiments of the present invention will be described below. Matters necessary for carrying out the present invention other than those specifically mentioned in this specification can be understood by those skilled in the art based on the teachings regarding the implementation of the invention described in this specification and the common general technical knowledge at the time of filing. The present invention can be carried out based on the contents disclosed in this specification and the common general technical knowledge in the art.

[0009] In addition, in the following drawings, components or parts that perform the same function may be denoted by the same reference numerals, and redundant explanations may be omitted or simplified. Furthermore, the embodiments shown in the drawings are shown schematically to clearly explain the present invention, and do not necessarily accurately represent the dimensions or scale of the products that are actually provided.

[0010] <Adhesive sheet> The adhesive sheet of the present invention has a base layer and an adhesive layer provided on one side of the base layer, and after immersion in a 50 wt % NaOH solution at 125°C for 180 minutes, the adhesive sheet experiences a mass loss of 3% or less, a reduction in the overall thickness of the adhesive sheet is 3 μm or less, and a shrinkage rate is within ±5%.

[0011] Fig. 1 is a cross-sectional view schematically illustrating the structure of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. As shown in Fig. 1, the pressure-sensitive adhesive sheet 1 includes a base layer 10 and a pressure-sensitive adhesive layer 20 provided on one side of the base layer 10, and the pressure-sensitive adhesive layer 20 is preferably provided over the entire surface of the base layer 10.

[0012] Although not shown, the pressure-sensitive adhesive sheet of the present invention may be provided with a release liner on the outside of the pressure-sensitive adhesive layer for the purpose of protecting the adhesive surface before use.

[0013] The concept of adhesive sheet as used herein may include those called adhesive tapes, adhesive labels, adhesive films, etc. The adhesive sheets disclosed herein may be in the form of sheets, or may be processed into various shapes. In some preferred embodiments, the adhesive sheet of the present invention may be provided in a continuous shape.

[0014] The pressure-sensitive adhesive sheet of the present invention has the following configuration.

[0015] After immersion of the PSA sheet in a 50 wt % NaOH solution at 125°C for 180 minutes, the mass loss is 3% or less, preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, with a preferred lower limit of 0.3%, a more preferred lower limit of 0.1%, and an even more preferred lower limit of 0. On the other hand, after immersion of the PSA sheet in a 50 wt % NaOH solution at 125°C for 180 minutes, the total thickness loss of the PSA sheet is 3 μm or less, preferably 2 μm or less, more preferably 1 μm or less, and an even more preferred lower limit of 0.5 μm or less, with a preferred lower limit of 0.3 μm, a more preferred lower limit of 0.1 μm, and an even more preferred lower limit of 0 μm.

[0016] Furthermore, the PSA sheet has a shrinkage rate within ±5% after immersion for 180 minutes in a 50 wt % NaOH solution at 125° C. The shrinkage rate is preferably within ±3%, more preferably within ±2%, even more preferably within ±1%, and preferably within ±0.3%, more preferably within ±0.1%, and even more preferably 0%.

[0017] If the mass loss, total thickness loss, and shrinkage rate of an adhesive sheet are each within the above ranges after the adhesive sheet is immersed in a 50 wt % NaOH solution at 125°C for 180 minutes, the adhesive sheet can have excellent adhesiveness, alkali resistance, and mechanical properties.

[0018] The mass loss, the total thickness reduction, and the shrinkage rate can be measured, for example, by the method described in the examples below.

[0019] Preferably, in the present invention, after the adhesive sheet is bonded to glass and then immersed in a 50 wt% NaOH solution at 125°C for 180 minutes, the edge erosion rate is 2% or less, or the edge erosion amount is 2 mm or less, and the peel force when the adhesive sheet is peeled from the glass at 23°C in a 180° direction at a pulling rate of 300 mm / min is 12 N / 20 mm or less.

[0020] The edge erosion rate is preferably 0.8% or less, more preferably 0.5% or less, even more preferably 0.3% or less, with a preferred lower limit of 0.2%, more preferably 0.1%, and even more preferably 0%. The edge erosion amount is preferably 1.5mm or less, more preferably 1.0mm or less, even more preferably 0.5mm or less, with a preferred lower limit of 0.3mm, more preferably 0.1mm, and even more preferably 0mm. The peel force when peeling the pressure-sensitive adhesive sheet from the glass at a pulling rate of 300mm / min in a 180° direction at 23°C is preferably 11N / 20mm or less, more preferably 10N / 20mm or less, even more preferably 9N / 20mm or less, with a preferred lower limit of 1.0N / 20mm, more preferably 0.5N / 20mm, and even more preferably 0N / 20mm.

[0021] When the edge erosion rate, edge erosion amount and peel strength are within the above ranges after the pressure-sensitive adhesive sheet is attached to glass, the pressure-sensitive adhesive sheet can have excellent adhesion, alkali resistance and mechanical properties.

[0022] The edge erosion amount or edge erosion rate refers to the depth to which the etching solution has penetrated into the edge of the adhesive sheet, measured after the adhesive sheet and glass are immersed in a 50 wt% NaOH solution at 125°C for 180 minutes and then removed, or the ratio of this depth to the total thickness of the adhesive sheet.

[0023] The edge erosion rate, edge erosion amount and peel force can be measured, for example, by the method described in the examples below.

[0024] Preferably, the pressure-sensitive adhesive sheet exhibits a peel strength of 0.5 N / 20 mm or greater when attached to glass and then peeled from the glass in a 180° direction at a pulling rate of 300 mm / min at 23° C. The peel strength is preferably 1.0 N / 20 mm or greater, more preferably 1.5 N / 20 mm or greater, and even more preferably 2.0 N / 20 mm or greater, with the upper limit being preferably 8.0 N / 20 mm, more preferably 7.0 N / 20 mm, and even more preferably 6.0 N / 20 mm.

[0025] [Adhesive layer] The pressure-sensitive adhesive layer of the present invention may be a layer formed from a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition contains 100 parts by weight of a rubber elastomer, 5 to 50 parts by weight of a functional resin, 0.5 to 5 parts by weight of a crosslinking agent, and 0.2 to 2 parts by weight of a release aid. The form of the pressure-sensitive adhesive composition is not particularly limited, and may be a pressure-sensitive adhesive composition in various forms, such as a water-dispersible type, a solvent-based type, a hot-melt type, or an active energy ray-curable type (e.g., a photocurable type).

[0026] Each component of the pressure-sensitive adhesive composition of the present invention will be described below.

[0027] (rubber elastomer) In the present invention, the rubber elastomer is at least one saturated rubber elastomer selected from saturated ethylene propylene rubber, silicone rubber, fluororubber, and thermoplastic styrene butadiene rubber (SEBS). By using a saturated rubber elastomer in the present invention, the PSA sheet can have excellent adhesiveness, alkali resistance, and mechanical properties.

[0028] In contrast, in the present invention, if unsaturated rubber elastomers such as unsaturated styrene-isoprene-styrene rubber (SIS), styrene-butadiene rubber (SBR), natural rubber, or butadiene rubber are used, it is difficult to obtain an adhesive sheet with excellent adhesion, alkali resistance, and mechanical properties.

[0029] The Shore hardness of the rubber elastomer is 30 to 100, preferably 35 to 80, and more preferably 40 to 50. The Shore hardness can be measured by a known method using a Shore hardness tester.

[0030] (functional resin) The pressure-sensitive adhesive composition of the present invention contains a functional resin, which may be at least one of epoxy resin, furan resin, silicone resin, urethane resin, terpene resin, and petroleum resin.

[0031] The epoxy resin is not particularly limited, and various epoxy resins can be used, such as triphenylmethane-type epoxy resins, cresol novolac-type epoxy resins, biphenyl epoxy resins, modified bisphenol A-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, modified bisphenol F-type epoxy resins, dicyclopentadiene-type epoxy resins, phenol novolac-type epoxy resins, and phenoxy resins. These epoxy resins can be used alone or in combination of two or more. From the viewpoint of ensuring the reactivity of the epoxy resin, epoxy resins with an epoxy equivalent of 150 to 250 g / eq, a softening point or melting point of 50 to 130°C, and solid at room temperature are preferred. Among these, triphenylmethane-type epoxy resins, cresol novolac-type epoxy resins, and biphenyl epoxy resins are more preferred from the viewpoint of reliability. Bisphenol F-type epoxy resins are also preferred.

[0032] Examples of furan resins include furfuryl alcohol resins, furfural acetone resins, and furfural-acetone-formaldehyde resins.

[0033] Examples of silicone resins include polymethyl silicone resins, polyethyl silicone resins, polyaryl silicone resins, and polyalkylaryl silicone resins.

[0034] Examples of urethane resins include flexible urethane foam, rigid urethane foam, thermoplastic urethane, and aqueous urethane dispersion.

[0035] Examples of terpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, etc., and modified terpene resins obtained by modifying these terpene resins (phenol-modified, aromatic-modified, hydrogenated, hydrocarbon-modified, etc.) (e.g., terpene phenol resins, styrene-modified terpene resins, aromatic-modified terpene resins, hydrogenated terpene resins).

[0036] Examples of petroleum resins include aromatic petroleum resins, aliphatic petroleum resins, alicyclic petroleum resins (aliphatic cyclic petroleum resins), aliphatic aromatic petroleum resins, aliphatic alicyclic petroleum resins, and hydrogenated petroleum resins. Examples of aromatic petroleum resins include polymers using one or more vinyl-containing aromatic hydrocarbons having 8 to 10 carbon atoms (styrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, α-methylstyrene, β-methylstyrene, indene, methylindene, etc.). Examples of aromatic petroleum resins that can be preferably used include aromatic petroleum resins (i.e., "C9 petroleum resins") obtained from fractions such as vinyltoluene and indene (i.e., "C9 petroleum fractions"). Examples of aliphatic petroleum resins include polymers obtained from one or more dienes selected from C4 or C5 olefins (e.g., butene-1, isoprene, pentene-1, etc.), butadiene, piperylene, 1,3-pentadiene, isoprene, etc. Furthermore, as the aliphatic petroleum resin, for example, aliphatic petroleum resins (i.e., "C4 petroleum resins," "C5 petroleum resins," etc.) obtained from fractions such as butadiene, piperylene, and isoprene (i.e., "C4 petroleum fractions," "C5 petroleum fractions," etc.) can be preferably used. Examples of alicyclic petroleum resins include alicyclic hydrocarbon resins obtained by cyclization and dimerization of aliphatic petroleum resins (i.e., "C4 petroleum resins," "C5 petroleum resins," etc.) followed by polymerization; polymers of cyclic diene compounds (cyclopentadiene, dicyclopentadiene, ethylene norbornane, dipentene, ethylene bicycloheptene, vinylcycloheptene, tetrahydroindene, vinylcyclohexene, limonene, etc.) or hydrogenated resins thereof; alicyclic hydrocarbon resins obtained by hydrogenating the aromatic rings of the aromatic hydrocarbon resins; and the following aliphatic aromatic petroleum resins. Examples of aliphatic aromatic petroleum resins include styrene-olefin copolymers. Furthermore, as the aliphatic aromatic petroleum resin, so-called "C5 / C9 copolymer petroleum resin" and the like can be used.

[0037] The acid value of the functional resin is 5 mgKOH / g or less, preferably 2 mgKOH / g or less, and more preferably 0.5 mgKOH / g or less. When the acid value of the functional resin is within this range, the PSA sheet can have excellent adhesiveness, alkali resistance, and mechanical properties.

[0038] In the pressure-sensitive adhesive composition, the amount of functional resin used is 5 to 50 parts by weight, preferably 10 to 40 parts by weight, and more preferably 20 to 30 parts by weight, per 100 parts by weight of rubber elastomer.

[0039] (Crosslinking agent) In the present invention, the pressure-sensitive adhesive composition contains a crosslinking agent. As the crosslinking agent, a commonly used crosslinking agent can be used, such as an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, a melamine-based crosslinking agent, an aziridine-based crosslinking agent, a metal chelate-based crosslinking agent, etc. These crosslinking agents may be used alone or in combination of two or more.

[0040] Specific examples of epoxy crosslinking agents include, but are not limited to, bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, and polyglycerin polyglycidyl ether.

[0041] Isocyanate crosslinking agents include 1,2-ethylene diisocyanate; butane diisocyanates such as 1,2-butane diisocyanate, 1,3-butane diisocyanate, and 1,4-butane diisocyanate; hexane diisocyanates such as 1,2-hexane diisocyanate, 1,3-hexane diisocyanate, 1,4-hexane diisocyanate, 1,5-hexane diisocyanate, 1,6-hexane diisocyanate, and 2,5-hexane diisocyanate; and 2-methyl-1,5-pentaisocyanate. toluene diisocyanate; isophorone diisocyanate; cyclohexyl diisocyanates such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, and 1,4-cyclohexyl diisocyanate; cyclopentyl diisocyanates such as 1,2-cyclopentyl diisocyanate and 1,3-cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate , hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate; 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, 2-nitrobiphenyl-4,4'-diisocyanate, 2,2'-diphenyl Examples of the diisocyanate include phenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, and xylylene-1,3-diisocyanate.

[0042] Examples of the melamine-based crosslinking agent include hexamethylol melamine and butylated melamine resin.

[0043] Examples of the aziridine crosslinking agent include trimethylolpropane tris[3-(1-aziridinyl)propionate] and trimethylolpropane tris[3-(1-(2-methyl)aziridinylpropionate)].

[0044] Examples of the metal chelate crosslinking agent include aluminum chelate compounds, titanium chelate compounds, zinc chelate compounds, zirconium chelate compounds, iron chelate compounds, cobalt chelate compounds, nickel chelate compounds, tin chelate compounds, manganese chelate compounds, and chromium chelate compounds.

[0045] In the pressure-sensitive adhesive composition, the amount of the crosslinking agent used is 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight, and more preferably 2 to 3 parts by weight, per 100 parts by weight of the rubber elastomer.

[0046] (peeling aid) In the present invention, the pressure-sensitive adhesive composition contains a release aid, such as a polysiloxane-based release aid, a paraffin-based release aid, polyethylene wax, or an acrylic polymer.

[0047] In the pressure-sensitive adhesive composition, the amount of the release aid used is 0.2 to 2 parts by weight, preferably 0.5 to 1.5 parts by weight, and more preferably 0.8 to 1 part by weight, per 100 parts by weight of the rubber elastomer.

[0048] In addition to the above-mentioned components, the pressure-sensitive adhesive composition of the present invention may contain, as necessary, various additives commonly used in the field of pressure-sensitive adhesives, such as photoinitiators, plasticizers, softeners, antioxidants, antioxidants, etc. For each of these additives, conventionally known additives can be used by a general method, within the scope of not impairing the effects of the present invention.

[0049] Preferably, the pressure-sensitive adhesive composition of the present invention does not contain a plasticizer.

[0050] (Production of Pressure-Sensitive Adhesive Composition) In the present invention, the pressure-sensitive adhesive composition can be produced by a conventionally known method, for example, by dissolving the functional resin, crosslinking agent, release aid, and other additives that may be contained in an organic solvent such as toluene or xylene, and dispersing the resulting mixture in a rubber elastomer.

[0051] (Formation of adhesive layer) The PSA layer disclosed herein can be formed by a conventionally known method. For example, a method (direct method) can be used in which a PSA composition is directly applied (typically coated) onto the substrate layer and dried to form a PSA layer. Alternatively, a method (transfer method) can be used in which a PSA composition is applied onto a releasable surface (release surface) and dried to form a PSA layer on the surface, and then the PSA layer is transferred onto the substrate layer. From the viewpoint of productivity, the transfer method is preferred. The release surface can be the surface of a release liner, the backside of a release-treated substrate layer, or the like. The PSA layer disclosed herein is typically formed continuously, but is not limited to this form. For example, the PSA layer may be formed in a regular or irregular pattern, such as a dotted or striped pattern.

[0052] The pressure-sensitive adhesive composition can be applied using a conventionally known coater such as a gravure roll coater, a die coater, a rod coater, etc. Alternatively, the pressure-sensitive adhesive composition may be applied by impregnation, curtain coating, or the like.

[0053] From the viewpoint of promoting the crosslinking reaction and improving production efficiency, the pressure-sensitive adhesive composition is preferably dried by heating. The drying temperature can be, for example, about 40 to 150° C., and is usually preferably about 60 to 130° C. For purposes such as adjusting the migration of components within the pressure-sensitive adhesive layer, promoting the crosslinking reaction, and relaxing distortion that may exist within the base film or pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition may be further aged after drying.

[0054] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but considering the balance between adhesiveness and cohesion to the adherend, the thickness of the pressure-sensitive adhesive layer is preferably 1 to 40 μm, more preferably 3 to 35 μm. By setting the thickness of the pressure-sensitive adhesive layer within this range, good adhesiveness can be achieved.

[0055] [Base material layer] The substrate layer of the pressure-sensitive adhesive sheet of the present invention is a monolayer film formed of one or more types of polyolefin or fluorinated polyolefin, or a composite film formed by combining two or more types of the monolayer films.

[0056] The polyolefin is at least one selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP), and the fluorinated polyolefin is at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

[0057] The surface of the substrate layer of the present invention may be subjected to any surface treatment in order to improve adhesion and retention with adjacent layers, etc. Examples of the surface treatment include chemical or physical treatments such as chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment, and coating treatment.

[0058] The thickness of the substrate layer of the present invention is 5 to 100 μm, more preferably 30 to 60 μm.

[0059] In one embodiment, the interior and / or surface of the substrate layer may contain an antistatic agent. Any appropriate antistatic agent can be used as the antistatic agent contained in the interior and / or surface of the substrate layer as long as the effects of the present invention can be obtained. For example, the antistatic agents described above for the pressure-sensitive adhesive layer can be used.

[0060] The method for incorporating the antistatic material into the base material is not particularly limited as long as it can uniformly mix the antistatic material into the resin used in the base material. For example, a method for incorporating the antistatic material into the base material using a heated roller, a Banbury mixer, a pressure kneader, a twin-screw kneader, or the like can be used.

[0061] [Undercoat layer] The pressure-sensitive adhesive sheet of the present invention may further include an undercoat layer. The undercoat layer is provided between the substrate layer 10 and the pressure-sensitive adhesive layer 20.

[0062] The undercoat layer forming material is not particularly limited, but one or more of urethane-based resins, epoxy-based resins, polyester-based resins, acrylic-based resins, polyamide-based resins, melamine-based resins, olefin-based resins, polystyrene-based resins, phenol-based resins, isocyanurate-based resins, polyvinyl acetate-based resins, etc. can be used.

[0063] In some preferred embodiments, the undercoat layer preferably contains at least one selected from the group consisting of thermosetting acrylic, urethane, and epoxy resins, and is preferably an acrylic matte resin or an epoxy resin.

[0064] In some preferred embodiments, the undercoat layer preferably contains an antistatic agent. This improves the antistatic properties of the PSA sheet and sufficiently suppresses peel electrification voltage. The undercoat layer may have a single-layer structure or a multi-layer structure of two or more layers. In a configuration in which a multi-layer undercoat layer is disposed, it is preferred that at least one layer therein (typically, at least one layer including the layer in contact with the substrate layer) is an undercoat layer containing an antistatic agent.

[0065] As the antistatic agent, for example, the antistatic agents described above for the pressure-sensitive adhesive layer can be used.

[0066] In some embodiments, the undercoat layer may further contain a crosslinking agent. The crosslinking agent may be appropriately selected from melamine-based, isocyanate-based, epoxy-based, and other crosslinking agents commonly used for crosslinking resins. This allows the undercoat layer to have good anchoring properties to the substrate layer.

[0067] In some preferred embodiments, the undercoat layer is preferably formed using a back surface treatment agent. The back surface treatment agent that can be used to form the undercoat layer is not particularly limited, but known or commonly used treatment agents such as silicone-based back surface treatment agents, fluorine-based back surface treatment agents, and long-chain alkyl-based back surface treatment agents can be used depending on the purpose and application. The back surface treatment agents may be used alone or in combination of two or more.

[0068] The thickness of the undercoat layer of the present invention is not particularly limited, but may be 0.05 to 1 μm, and preferably 0.1 to 0.5 μm.

[0069] (Method of manufacturing pressure-sensitive adhesive sheet) The pressure-sensitive adhesive sheet of the present invention can be produced by any appropriate method, such as a method of applying a pressure-sensitive adhesive composition onto a substrate layer, or a method of applying a pressure-sensitive adhesive composition onto any appropriate substrate to form a coating layer, and then transferring the coating layer onto the substrate layer.

[0070] Any appropriate coating method can be used as a method for applying the pressure-sensitive adhesive composition. For example, each layer may be formed by coating and then drying. Examples of the coating method include coating using a multi-coater, die coater, gravure coater, applicator, or bar coater, air knife coating, reverse roller coating, lip coating, dip coating, offset printing, flexographic printing, and screen printing. Examples of the drying method include natural drying and heat drying. When heat drying is performed, the heating temperature can be set to any appropriate temperature depending on the properties of the material to be dried.

[0071] (Application) The pressure-sensitive adhesive sheet disclosed herein can be attached to various members and equipment for protection and other purposes.

[0072] <Glass etching method> The present invention further relates to a glass etching method, which comprises attaching the pressure-sensitive adhesive sheet according to the present invention to one or more main surfaces of glass, bringing the one or more main surfaces of the glass into contact with an etching solution, and then peeling off the pressure-sensitive adhesive sheet.

[0073] In the present invention, the type of etching solution is not particularly limited. The etching solution may contain 20 to 60 wt% of one or more alkaline hydroxides. The alkaline hydroxides are sodium hydroxide (NaOH), potassium hydroxide (KOH), or a combination of sodium hydroxide and potassium hydroxide.

[0074] The etching solution may further contain one or more of an alkali metal phosphate, an alkali metal carbonate, and a chelating agent. In one embodiment, the concentration of one or more of the alkali metal phosphate, the alkali metal carbonate, and the chelating agent in the etching solution is 0.1 to 20 wt%, preferably 0.5 to 15 wt%, and more preferably 1 to 10 wt%. The alkali metal phosphate may be one or more inorganic orthophosphates or pyrophosphates containing sodium ions or potassium ions, including, but not limited to, sodium phosphates such as Na3PO4 and Na4P2O7, and potassium phosphates such as K3PO4 and K4P2O7. The alkali metal carbonate may be one or more of Na2CO3 and K2CO3. The chelating agent may be one or more of ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), citric acid, salicylic acid, glycine, oxalic acid, and disodium EDTA.

[0075] The temperature of the etching solution is not particularly limited, but is usually 100 to 130° C., and preferably 110 to 120° C. The time for which one or more main surfaces of the glass are in contact with the etching solution is also not particularly limited, but is usually 60 to 200 minutes, preferably 80 to 180 minutes, and more preferably 100 to 120 minutes.

[0076] The pressure-sensitive adhesive sheet of the present invention, when stuck to glass, can be easily peeled off from the glass even when etched with an alkaline etching solution, and has excellent adhesiveness, alkali resistance and mechanical properties. [Example]

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Evaluation methods in the examples are as follows. Unless conditions are specifically described in the examples, the evaluations were carried out under general conditions or conditions recommended by the manufacturer. Unless otherwise specified, commercially available general products can be used for all materials and equipment used.

[0078] Example 1 A petroleum resin (20 parts by weight) with an acid value of 0.1 mg KOH / g, a crosslinking agent (Bayer L75C, main component: toluene diisocyanate) (1 part by weight), and a release aid (ADEKA PC-10, polyoxyethyl polyoxypropyl glycerol) (0.5 parts by weight) were dissolved in toluene, and then mixed with thermoplastic styrene butadiene rubber (SEBS) (100 parts by weight) to obtain a pressure-sensitive adhesive composition.

[0079] The acrylic matte resin solution was applied to one side of a 50 μm-thick HDPE film (HD-PE002 from Shenzhen Hongda Technology Materials Co., Ltd.), which served as the substrate layer, and then dried in a suspension oven at 80 °C for 1 minute to form an undercoat layer with a thickness of 0.2 μm.

[0080] The pressure-sensitive adhesive composition was applied to the undercoat layer on the side opposite the substrate layer, and then dried to obtain a 15 μm-thick pressure-sensitive adhesive layer. The drying conditions were heating at 130° C. for 2 minutes. Finally, a pressure-sensitive adhesive sheet having an undercoat layer between the substrate layer and the pressure-sensitive adhesive layer was obtained.

[0081] The pressure-sensitive adhesive sheet was attached to a glass plate, immersed in a 50 wt % NaOH solution at 125° C. for 180 minutes, and then peeled off from the glass plate.

[0082] The properties of the pressure-sensitive adhesive sheet were measured, and the results are shown in the table below.

[0083] Examples 2 to 15 and Comparative Examples 1 to 7 Except for changing the type and amount of each component of the pressure-sensitive adhesive composition as shown in the table below, changing the type and thickness of the substrate layer, and not using an undercoat layer, pressure-sensitive adhesive sheets were obtained in the same manner as in Example 1. The evaluation results are shown in the table below. In the table below, HDPE: High density polyethylene PET: Polyethylene terephthalate PP: Polypropylene PTFE: Polytetrafluoroethylene SEBS: Thermoplastic styrene butadiene rubber SIS: Unsaturated styrene-isoprene-styrene rubber PVC: Polyvinyl chloride The "parts" represent parts by weight, and "-" represents unmeasured.

[0084] [Table 1]

[0085] [Table 2]

[0086] [Table 3]

[0087] [Table 4]

[0088] [Table 5]

[0089] [Table 6]

[0090] <Evaluation test> (1) Peel strength after bonding to glass (unetched) (N / 20mm, 23°C, 180°, 300mm / 10min)

[0091] Test pieces measuring 20 mm wide x 150 mm long were cut from the pressure-sensitive adhesive sheets prepared in each Example and Comparative Example. Glass washed with toluene was used as the adherend. A 2 kg roller was moved back and forth once under a standard environment of 23°C and 50% RH to press the exposed adhesive surface onto the adherend. The test piece thus pressed onto the adherend was left under the standard environment for 30 minutes, and then peeled at a tensile speed of 300 mm / min and a peel angle of 180° using a universal material testing machine (manufactured by Shimadzu Corporation, product name "AG-X plus Electronic Universal Testing Machine") in accordance with JIS Z 0237, and the force required for the peel (N / 20 mm) was measured.

[0092] (2) Peel strength after bonding to glass and etching (N / 20mm, 23°C, 180°, 300mm / 10min) As in (1) above, the pressure-sensitive adhesive sheets prepared in each Example and Comparative Example were attached to glass. The pressure-sensitive adhesive sheets were then immersed together with the glass in a 50 wt% NaOH solution at 125°C for 180 minutes, removed, and left in a standard environment of 23°C and 50% RH for 30 minutes. After that, the sheets were peeled at a tensile speed of 300 mm / min and a peel angle of 180° using a universal material testing machine (manufactured by Shimadzu Corporation, product name "AG-X plus Electronic Universal Testing Machine") in accordance with JIS Z 0237, and the force required for peeling (N / 20 mm) was measured.

[0093] (3) Alkali resistance evaluation The pressure-sensitive adhesive sheets prepared in each example and comparative example were cut into 100mm x 100mm sheets and attached to glass. The pressure-sensitive adhesive sheets were then immersed together with the glass in a 50 wt% NaOH solution at 125°C for 180 minutes and then removed. Three points on the pressure-sensitive adhesive sheet were randomly selected, and the corrosion depth was measured using a microscope. The evaluation criteria were as follows: If the depth of the etching solution penetrating the edge of the adhesive sheet was 1 mm or less, or if the liquid penetration area accounted for 1% or less of the total area of the adhesive sheet, a rating of 5 was given. If the depth of the etching solution penetrating the edge of the adhesive sheet was more than 1 mm but not more than 2 mm, or if the liquid penetration area accounted for more than 1% but not more than 2% of the total area of the adhesive sheet, the rating was 4. If the depth of the etching solution penetrating the edge of the adhesive sheet exceeded 2 mm, or if the liquid penetration area accounted for more than 2% of the total area of the adhesive sheet, the sheet was rated as 3 (NG: Fail). If the adhesive sheet peeled off but no corrosion occurred, the test piece was rated as 2 (NG: Fail). If the adhesive sheet was corroded, it was rated as 1 (NG: Fail).

[0094] (4) Adhesive residue The pressure-sensitive adhesive sheets prepared in each example and comparative example were attached to glass, and then the pressure-sensitive adhesive sheet and the glass were immersed in a 50 wt% NaOH solution at 125°C for 180 minutes, after which they were removed. The test pieces thus pressed onto the adherend were left in a standard environment of 23°C and 50% RH for 3 days, and then peeled off at a pulling rate of 300 mm / min, after which the presence or absence of adhesive residue on the glass surface was visually confirmed. If there was no adhesive residue visible to the naked eye, it was marked with "◎", if there was slight adhesive residue visible to the naked eye, it was marked with "○", and if there was severe adhesive residue visible to the naked eye, it was marked with "●".

[0095] (5) Overall thickness reduction The thickness of the pressure-sensitive adhesive sheets prepared in each Example and Comparative Example was measured, and then the pressure-sensitive adhesive sheets were immersed in a 50 wt % NaOH solution at 125°C for 180 minutes, removed, dried, and then the thickness of the pressure-sensitive adhesive sheets was measured. The total thickness loss of the pressure-sensitive adhesive sheets was obtained by subtracting the thickness after immersion from the thickness before immersion. When the reduction in the total thickness was 1 μm or less, it was marked as “Excellent.” When the reduction in the total thickness was more than 1 μm and 3 μm or less, it was marked as "Good." When the reduction in total thickness was more than 3 μm, it was marked with a black circle.

[0096] (6) Mass loss The weight of the pressure-sensitive adhesive sheet prepared in each example and comparative example was measured, and then the pressure-sensitive adhesive sheet was immersed in a 50 wt% NaOH solution at 125°C for 180 minutes, removed, dried, and then the weight of the pressure-sensitive adhesive sheet was measured. The weight after immersion was subtracted from the weight before immersion to obtain the weight loss of the pressure-sensitive adhesive sheet. The mass loss was calculated in % based on the weight before immersion. When the mass loss was 1% or less, it was marked as "Excellent." When the mass loss was more than 1% and 3% or less, it was marked as "Good." If the mass loss was more than 3%, it was marked with a "●".

[0097] (7) Shrinkage rate The pressure-sensitive adhesive sheets prepared in each example and comparative example were cut into 100 mm x 100 mm sheets. The pressure-sensitive adhesive sheets were then immersed in a 50 wt% NaOH solution at 125°C for 180 minutes, removed, and the TD / MD lengths of the pressure-sensitive adhesive sheets were measured. The TD / MD lengths after immersion were subtracted from the TD / MD lengths before immersion (or vice versa) to obtain the amount of shrinkage of the pressure-sensitive adhesive sheet. The shrinkage percentage was calculated in % based on the TD / MD lengths before immersion. When the shrinkage rate was within ±3%, it was marked as "Excellent." When the shrinkage rate was more than ±3% and within ±5%, it was marked as "Good." If the shrinkage rate was more than ±5%, it was marked with a black circle.

[0098] As shown in the table above, the pressure-sensitive adhesive sheets of Examples 1 to 15 had excellent adhesiveness, alkali resistance, and mechanical properties, and could be easily peeled off after use without leaving any residue or stains. In contrast, the pressure-sensitive adhesive sheets of Comparative Examples 1 to 7 were unable to achieve both adhesiveness, alkali resistance, and mechanical properties. [Explanation of symbols]

[0099] 1 adhesive sheet 10 Base material layer 20 adhesive layer

Claims

1. A pressure-sensitive adhesive sheet having a base layer and a pressure-sensitive adhesive layer provided on one side of the base layer, The pressure-sensitive adhesive sheet is characterized in that, after immersion in a 50 wt % NaOH solution at 125°C for 180 minutes, the pressure-sensitive adhesive sheet experiences a mass loss of 3% or less, a reduction in the total thickness of the pressure-sensitive adhesive sheet is 3 μm or less, and a shrinkage rate is within ±5%.

2. the pressure-sensitive adhesive sheet is attached to glass, and then the pressure-sensitive adhesive sheet is immersed in a 50 wt % NaOH solution at 125°C for 180 minutes, after which the edge erosion rate is 2% or less, or the edge erosion amount is 2 mm or less; 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the peel strength when the pressure-sensitive adhesive sheet is peeled from the glass at 23° C. in a 180° direction at a pulling rate of 300 mm / min is 12 N / 20 mm or less.

3. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet has a peel strength of 0.5 N / 20 mm or more when the pressure-sensitive adhesive sheet is attached to glass and then peeled from the glass at a pulling rate of 300 mm / min in a 180° direction at 23°C.

4. the substrate layer is a monolayer film formed from one or more of polyolefin or fluorinated polyolefin, or a composite film combining two or more of the monolayer films, 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the thickness of the substrate layer is 5 to 100 μm.

5. the polyolefin is at least one selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP); 5. The pressure-sensitive adhesive sheet according to claim 4, wherein the fluorinated polyolefin is at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

6. the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition comprises 100 parts by weight of a rubber elastomer, 5 to 50 parts by weight of a functional resin, 0.5 to 5 parts by weight of a crosslinking agent, and 0.2 to 2 parts by weight of a release aid; 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 1 to 40 μm.

7. the rubber elastomer is at least one saturated rubber elastomer selected from saturated ethylene propylene rubber, silicone rubber, fluororubber, and thermoplastic styrene butadiene rubber (SEBS); 7. The pressure-sensitive adhesive sheet according to claim 6, wherein the rubber elastomer has a Shore hardness of 30 to 100.

8. 7. The pressure-sensitive adhesive sheet according to claim 6, wherein the functional resin is at least one selected from the group consisting of epoxy resins, furan resins, silicone resins, urethane resins, terpene resins, and petroleum resins.

9. The pressure-sensitive adhesive sheet according to claim 8, wherein the functional resin has an acid value of 5 mg KOH / g or less.

10. The pressure-sensitive adhesive sheet according to claim 1 or 2, further comprising an undercoat layer, the undercoat layer being provided between the base layer and the pressure-sensitive adhesive layer, and the undercoat layer having a thickness of 0.05 to 1 μm.

11. A glass etching method comprising: attaching the adhesive sheet according to claim 1 or 2 to one or more main surfaces of glass; contacting the one or more main surfaces of the glass with an etching solution; and then peeling off the adhesive sheet.

12. 12. The glass etching method according to claim 11, wherein the temperature of the etching solution is 100 to 130° C., and the time for which the one or more main surfaces of the glass are in contact with the etching solution is 60 to 200 minutes.

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