JP5906222B2 - Surface protection film for chemical polishing - Google Patents

Description

  The present invention relates to a surface protective film for chemical polishing. More specifically, the present invention relates to a surface protective film used in a chemical polishing process for a glass substrate, which is formed on the glass substrate as an adherend, on the ITO surface for a touch panel sensor or on the opposite side. A surface protective film for chemical polishing that can be used for protecting an adherend from a chemical polishing liquid (etching liquid) by bonding to a surface.

  Conventionally, for the purpose of reducing the thickness of a glass substrate or the like, it is known that after a surface protective film is bonded to one surface of a glass substrate or the like, the other surface is chemically polished using an etching solution. (For example, see Patent Documents 1 and 2).

  Patent Document 1 states that “the conventional chemical polishing method uses strong acid hydrofluoric acid as an etching solution, so that the masking layer is eroded during etching or peels off from a glass substrate (LCD glass substrate, etc.). In order to solve the problem, on the other side of the glass substrate, a coating layer having high chemical resistance and adhesion is formed on the surface of the glass substrate for protection. A method is shown in which the coating layer is peeled and removed after being thinned by etching. In order to protect one surface during etching, it is necessary to use a coating layer having a sufficiently strong adhesive force. However, when the coating layer is peeled off from a thinned substrate or the like, there is a crack in the glass substrate. May occur. For this reason, the method disclosed in Patent Document 1 has a problem that it is difficult to peel the coating layer from the glass substrate or the like after being thinned.

  Further, in Patent Document 2, when etching a printed wiring board made of metal, glass, ceramic, plastic, etc., or a plate-like board made of other crystalline brittle materials, etc., it is bonded to the non-etched surface, A releasable pressure-sensitive adhesive tape used for masking during an etching process is disclosed. In the invention described in Patent Document 2, the pressure-sensitive adhesive layer is composed of a (meth) acrylic resin composition that does not substantially contain a hydrophilic carboxyl group, thereby allowing an etching solution such as acid or alkali to enter. Suppressed. As a result, erosion of the non-etched surface by the etching solution can be suppressed, and the adhesive layer can be easily peeled off without cohesive failure after completion of etching. However, the etching resistance was “a 25 mm square adhesive tape sample was bonded to the mirror surface side of a 6-inch silicon wafer, and left for 1 hour, and then immersed in a 10 wt% NaOH aqueous solution at 70 ° C. for 20 minutes. In the case where the intrusion of the etching solution was not confirmed, the invasion of the etching solution was confirmed in the immersion for 10 minutes or more and less than 20 minutes, and the invasion of the etching solution was confirmed in the immersion for less than 10 minutes. The product was ranked as x. ”, And the etching resistance to an etching solution containing a hydrofluoric acid aqueous solution as a main component for chemically polishing a glass substrate was insufficient.

  The conventional touch panel has a structure in which an ITO glass (film) layer is laminated in two layers under a cover glass. Later, due to the trend of simplified structure and thinner film, the demand for OGS (one glass solution) panels with a single glass substrate and touch sensor layers on both surfaces of the glass substrate has increased recently. (For example, see Non-Patent Documents 1 and 2).

JP 2004-182586 A JP 2009-209223 A

Nihon Keizai Shimbun, “Japan NanoOpt develops a touch glass integrated touch panel”, [online], May 18, 2012, Internet <http: // www. nikkei. com / article / DGXNASFK1703Y_X10C12A5000000 /> "Is the next iPad mini display using touch panel / cover glass integrated technology?", [Online], January 10, 2013, Internet <http: // taisy0. com / 2013/01/10/13280. html>

  In the case of an OGS panel, a touch sensor layer is provided on both surfaces of a large-sized glass substrate and then cut into a size of a small panel such as a smartphone. In order to remove the burrs on the end face of the cut glass substrate and make it smooth, a chemical polishing process is performed using an etching solution whose main component is hydrofluoric acid. A hydrofluoric acid resistant protective sheet is used to protect both surfaces of the glass substrate during the chemical polishing process. However, the conventional hydrofluoric acid-resistant protective sheet has a problem that even if the intrusion of hydrofluoric acid is prevented, the adhesive surface contaminates the panel surface after the hydrofluoric acid-resistant protective sheet is peeled off. . To date, there has been no hydrofluoric acid-resistant protective sheet that not only prevents entry of hydrofluoric acid but also does not cause adhesive residue.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the surface protection film for chemical polishing which not only prevents the penetration | invasion of etching liquid, but the adhesive residue does not generate | occur | produce on a to-be-adhered body.

  In the present invention, a resin film having a thickness of 75 μm or more is used as a base material, and an alkyl (meth) acrylate monomer having a C1-C14 alkyl group, at least one of a hydroxyl group-containing vinyl monomer and a nitrogen-containing vinyl monomer. A pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing an acrylic copolymer containing a copolymerizable vinyl monomer. In addition, this pressure-sensitive adhesive layer does not contain a carboxyl group-containing monomer (avoids containing a carboxyl group-containing monomer and prevents the ITO layer in contact with the pressure-sensitive adhesive layer from corroding), and further uses a silane coupling agent in combination. As a result, water repellency was added and the problems of the prior art were solved.

That is, the present invention is a chemical polishing surface protective film having a pressure-sensitive adhesive layer on one side of a resin film substrate, wherein the resin film substrate has a thickness of 75 μm or more, and the pressure-sensitive adhesive layer is an acrylic type It is formed using an acrylic pressure-sensitive adhesive composition containing a copolymer, a silane coupling agent, and a crosslinking agent, and the acrylic copolymer is an alkyl (meta) having a C1-C14 alkyl group. A) a copolymer obtained by copolymerizing an acrylate monomer and at least one copolymerizable vinyl monomer selected from the group of a hydroxyl group-containing vinyl monomer and a nitrogen-containing vinyl monomer without including a carboxyl group-containing monomer; The chemical polishing surface protective film is bonded to a glass plate with the pressure-sensitive adhesive layer interposed therebetween, at a temperature of 27 ° C. and a concentration of 15%. After being immersed in an acid aqueous solution, at least 150 seconds or more at a portion where the distance from the end of the bonding surface of the surface protective film for chemical polishing of the adherend surface of the glass plate as the adherend is 80 μm or more There is provided a surface protective film for chemical polishing characterized by being free from permeation of hydrofluoric acid.

  The pressure-sensitive adhesive layer is laminated with a thickness of 10 to 35 μm, and when the pressure-sensitive adhesive layer has a thickness of 20 μm, the adhesive strength to the glass plate is preferably 0.1 to 1.5 N / 25 mm. .

The acrylic copolymer has (A) 80 to 95 parts by weight of at least one alkyl (meth) acrylate monomer having an alkyl group with C1 to C14, and (B) a hydroxyl group-containing vinyl monomer and nitrogen-containing compound. The pressure-sensitive adhesive layer comprises a copolymer obtained by copolymerizing 5 to 20 parts by weight of at least one copolymerizable vinyl monomer selected from the group of vinyl monomers without containing a carboxyl group-containing monomer, A pressure-sensitive adhesive comprising 100 parts by weight of the acrylic copolymer, 0.01 to 1 part by weight of (C) a silane coupling agent, and 0.01 to 10 parts by weight of (D) a crosslinking agent. It is preferably formed using a composition.

  It is preferable that the silane coupling agent has at least one organic functional group selected from the group consisting of an epoxy group, a (meth) acryloxy group, a mercapto group, and an amino group.

  The crosslinking agent is preferably an isocyanate compound.

  According to the present invention, it is possible to provide an adhesive film and a surface protective film that not only prevent intrusion of hydrofluoric acid but also have no problems such as adhesive residue.

It is the figure which showed the test method of the erodibility from the edge part of a glass plate. It is a graph which shows the relationship between the erosion time and the erosion distance of Example 1 and Comparative Example 1.

Hereinafter, the present invention will be described based on preferred embodiments.
In accordance with the increasing demand for touch panels in recent years, the present invention is for chemical polishing used in a chemical polishing process for manufacturing a panel structure (OGS) with a single-glass glass that is simplified and has a thinner touch panel structure. A surface protective film is provided. The present invention protects the panel surface (for example, ITO surface) from an etching solution during a chemical polishing process in which the panel end face is treated with hydrofluoric acid (which may be mixed with a strong acid such as sulfuric acid). The present invention relates to a surface protective film for chemical polishing that can be used as a sheet.
The conventional hydrofluoric acid-resistant protective sheet has not been able to sufficiently protect the panel surface due to permeation of hydrofluoric acid. Moreover, even if the surface of the panel could be protected, when peeled off after the chemical polishing process, there is a phenomenon such as the adhesive of the hydrofluoric acid resistant protective sheet contaminating the panel, and the removability is not good. The performance was not satisfactory.

  As for the surface protection film for chemical polishing of this invention, the adhesive layer is formed in the single side | surface of the resin film base material. This chemical polishing surface protective film is an adherend after being immersed in a hydrofluoric acid aqueous solution having a temperature of 27 ° C. and a concentration of 15% in a state of being bonded to a glass plate via the pressure-sensitive adhesive layer. There is no permeation of hydrofluoric acid for at least 150 seconds in a portion where the distance from the end of the bonding surface of the surface protective film for chemical polishing is 80 μm or more on the adherend surface of the glass plate. .

  In this invention, the thickness of the said resin film base material is 75 micrometers or more, and the said adhesive layer is formed using the acrylic adhesive composition containing a silane coupling agent and a crosslinking agent. Preferably, the alkyl group contains C1-C14 alkyl (meth) acrylate monomers and at least one copolymerizable vinyl monomer selected from the group of hydroxyl group-containing vinyl monomers and nitrogen-containing vinyl monomers. A pressure-sensitive adhesive layer is formed with a pressure-sensitive adhesive composition containing an acrylic copolymer. In addition, this pressure-sensitive adhesive layer does not contain a carboxyl group-containing monomer (the purpose is to prevent the ITO layer in contact with the pressure-sensitive adhesive layer from corroding by containing a carboxyl group-containing monomer), and also adds water repellency Therefore, it is preferable to use a silane coupling agent in combination.

In the pressure-sensitive adhesive film of the present invention, the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer is preferably composed of the following blending ratio.
(A) The carbon number of the alkyl group is at least one selected from the group consisting of C1 to C14 alkyl (meth) acrylate monomers of 80 to 95 parts by weight, and (B) a hydroxyl group-containing vinyl monomer and a nitrogen-containing vinyl monomer. 100 parts by weight of an acrylic copolymer containing 5 to 20 parts by weight of at least one copolymerizable vinyl monomer, 0.01 to 1 part by weight of (C) a silane coupling agent, and (D) cross-linking 0.01 to 10 parts by weight of the agent.

  (A) Examples of the acrylate monomer having an alkyl group with a C1 to C14 carbon number include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) ) Acrylate, decyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. The alkyl group of the acrylate monomer may be linear, branched or cyclic.

(B) The hydroxyl group-containing vinyl monomer and the nitrogen-containing vinyl monomer are selected from (A) monomers that are copolymerizable with an alkyl (meth) acrylate monomer having an alkyl group with C1 to C14.
Examples of the hydroxyl group-containing vinyl monomer (B) include hydroxyl groups such as 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and hydroxyethyl (meth) acrylate. Examples thereof include hydroxyl group-containing (meth) acrylamides such as group-containing (meth) acrylic acid esters, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide.

  Examples of the nitrogen-containing vinyl monomer (B) include cyclic nitrogen vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam and acryloylmorpholine, N-ethyl-N-methyl (meth) acrylamide, N-methyl-N- Propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, Dialkyl-substituted acrylamides such as N-diisopropyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl (meth) acrylate N-methyl-N-i Propylaminoethyl (meth) acrylate, N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-dimethylamino Propyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, dialkylamino acrylate such as N, N-dibutylaminoethyl (meth) acrylate, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylic Ruamido, N, dialkyl-substituted amino propyl (meth) acrylamide such as N- dipropylamino-propyl (meth) acrylamide. The nitrogen-containing vinyl monomer (B) may contain a hydroxyl group (for example, the hydroxyl group-containing (meth) acrylamide described above). In that case, the nitrogen-containing vinyl monomer is classified as a hydroxyl group-containing vinyl monomer. .

(C) As a silane coupling agent, at least one organic functional group and at least one hydrolyzable group are contained in one molecule, and the hydrolyzable group is an alkoxy group bonded to a silicon atom, or the like. There are certain compounds. It is preferable that the silane coupling agent has at least one organic functional group selected from the group consisting of an epoxy group, a (meth) acryloxy group, a mercapto group, and an amino group. Here, the (meth) acryloxy group means an acryloxy group (CH ₂ ═CHCOO—) or a methacryloxy group (CH ₂ ═C (CH ₃ ) COO—).

Examples of the silane coupling agent having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyl. Triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 5,6-epoxyhexyltrimethoxysilane, 5,6-epoxyhexylmethyldimethoxysilane, 5,6-epoxyhexylmethyldiethoxysilane, 5,6- Epoxy hex Such as triethoxy silane.
Examples of the silane coupling agent having a (meth) acryloxy group include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth) acryloxypropyltriethoxy. Examples thereof include silane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyldimethylethoxysilane, and 3- (meth) acryloxypropyldimethylmethoxysilane.
Examples of the silane coupling agent having a mercapto group include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and 3-mercaptopropyltriethoxysilane.
Examples of the silane coupling agent having an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) ) -3-aminopropyltriethoxysilane, 3- (methylamino) propyltrimethoxysilane, 3- (methylamino) propyltriethoxysilane and the like.
Moreover, the oligomerized alkoxy oligomer (silicone alkoxy oligomer) containing the said organic functional group etc. can also be used as a silane coupling agent.

(D) As a crosslinking agent, it is 1 or more types of crosslinking selected from the compound group which consists of bifunctional or more isocyanate type crosslinking agent (isocyanate compound), bifunctional or more epoxy type crosslinking agent, and aluminum chelate type crosslinking agent. It is preferable that it is an agent. A crosslinking agent may be used individually by 1 type, and may be used together in combination of 2 or more types.
Examples of the crosslinking agent for the isocyanate compound include diisocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), and burette modified products and isocyanurates of the diisocyanate. Examples thereof include polyisocyanate compounds such as modified products, trimethylolpropane, and adducts with trivalent or higher polyols such as glycerin.

  The pressure-sensitive adhesive composition may further contain known additives such as an antioxidant and an antistatic agent as other components. These may be used alone or in combination of two or more.

The surface protective film for chemical polishing of the present invention can be produced by forming a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition on one side of a resin film substrate. Moreover, in order to protect the adhesive surface of an adhesive layer, a release film (separator) can be laminated | stacked.
Examples of the resin film substrate used for the surface protective film for chemical polishing of the present invention include various polyolefin films such as polyethylene and polypropylene, various polyester films such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate. The resin film can be used. As the resin film substrate, a polyester film having a thickness of 75 μm or more is preferable because the film has high rigidity and is difficult to be deformed. When the thickness of the resin film substrate is less than 75 μm, the rigidity is low and the film is easily deformed. As a result, the chemical polishing surface protective film is bonded to the glass plate as the adherend through the adhesive layer. In this state, hydrofluoric acid easily penetrates between the pressure-sensitive adhesive layer and the glass plate, which is not preferable.

  The pressure-sensitive adhesive layer is preferably laminated with a thickness of 10 to 35 μm. Moreover, it is preferable that the adhesive force with respect to the said glass plate is 0.1-1.5N / 25mm when the thickness of the said adhesive layer is 20 micrometers. When the adhesive strength of the resin film substrate is greater than 1.5 N / 25 mm, when the surface protective film for chemical polishing is bonded to the glass plate as the adherend via the adhesive layer, and then peeled off This is not preferable because adhesive residue is likely to occur. Further, when the adhesive strength of the resin film substrate is less than 0.1 N / 25 mm, the adhesive is applied in a state where the chemical polishing surface protective film is bonded to the glass plate as the adherend through the adhesive layer. Since hydrofluoric acid easily permeates between the agent layer and the glass plate, it is not preferable. When the thickness of the pressure-sensitive adhesive layer is not 20 μm, the preferable numerical range of the adhesive force to the glass plate may be 0.1 to 1.5 N / 25 mm as in the case where the thickness of the pressure-sensitive adhesive layer is 20 μm. Alternatively, a numerical range larger than 0.1 to 1.5 N / 25 mm or a smaller numerical range may be used depending on the thickness of the pressure-sensitive adhesive layer.

  The surface protective film for chemical polishing of the present invention is bonded to a glass substrate which is an adherend, the ITO surface of the touch panel or the opposite surface thereof to protect the adherend from a chemical polishing liquid (etching liquid). Can be used. In this case, it is preferable that the resin film substrate and the pressure-sensitive adhesive layer have sufficient transparency. The touch panel may be a touch panel in which a transparent conductive film such as an ITO film is formed on at least one surface of a base material made of a glass substrate or the like. As a surface protection film for chemical polishing of this invention, it can stick to the surface on the said ITO film | membrane, or the surface on the opposite side so that peeling is possible through the said adhesive layer.

  Hereinafter, the present invention will be specifically described with reference to examples.

<Manufacture of acrylic copolymer>
[Example 1]
Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and the air in the reactor was replaced with nitrogen gas. Thereafter, 100 parts by weight of a solvent (ethyl acetate) was added to the reaction apparatus together with 95 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of 6-hydroxyhexyl acrylate. Thereafter, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, reacted at 65 ° C. for 8 hours, and the acrylic copolymer solution of Example 1 having a weight average molecular weight of 500,000 was obtained. 1 was obtained.
[Examples 2-6 and Comparative Examples 1-3]
Acrylic copolymer solution 1 used in Example 1 above, except that the monomer composition is as described in (A), (B-1), and (B-2) of Table 1. In the same manner as above, acrylic copolymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 3 were obtained.

<Production of pressure-sensitive adhesive composition and surface protective film for chemical polishing>
[Example 1]
For the acrylic copolymer solution 1 produced as described above (of which 100 parts by weight of the acrylic copolymer), as a crosslinking agent, 3.0 parts by weight of coronate HL and as a silane coupling agent, KBE- 0.02 part by weight of 403 (3-glycidoxypropyltriethoxysilane) was added and mixed by stirring to obtain a pressure-sensitive adhesive composition of Example 1. The pressure-sensitive adhesive composition is applied onto a release film made of a silicone resin-coated polyethylene terephthalate (PET) film, and then dried at 90 ° C. to remove the solvent, and the pressure-sensitive adhesive layer has a thickness of 20 μm. A film was obtained.
Thereafter, the adhesive film is transferred to one surface of a resin film substrate made of a polyethylene terephthalate (PET) film having a thickness of 75 μm, and “resin film substrate / adhesive layer / release film (silicone resin-coated PET film)” The surface protection film for chemical polishing of Example 1 having the laminated structure of was obtained.
[Examples 2-6 and Comparative Examples 1-3]
The composition of the additive is as described in (C) and (D) of Table 1, and the thickness of the resin film substrate is as described in Table 2 except that the thickness of the resin film substrate is as described in Table 2. In the same manner as the chemical polishing surface protective film, the chemical polishing surface protective films of Examples 2 to 6 and Comparative Examples 1 to 3 were obtained.

In Table 1, the compounding ratio of each component is indicated by enclosing numerical values in parts by weight in parentheses. In principle, the total of the parts by weight of the monomers (A), (B-1), and (B-2) (parts by weight of the copolymer) is 100 parts by weight, but this is not necessarily the case. . The total amount of monomers (parts by weight of copolymer) is 93 parts by weight in Example 6, 101 parts by weight in Comparative Example 1, 91 parts by weight in Comparative Example 2, and 105 parts by weight in Comparative Example 3.
In addition, Table 3 shows the names of the abbreviations of the components used in Table 1. Coronate (registered trademark) HX and L-45 are trade names of Nippon Polyurethane Industry Co., Ltd. D-110N is a trade name of Mitsui Chemicals, Inc. KBE-403, KBM-5103, KBE-903, KBM-802, X-41-1810, and X-41-1056 are trade names of Shin-Etsu Chemical Co., Ltd.

(Measurement method of adhesive strength)
The pressure-sensitive adhesive films in Examples 1 to 6 and Comparative Examples 1 to 3 were bonded to the non-tin surface washed with acetone of soda lime glass with a pressure roll. Then, after autoclaving at 50 ° C. and 0.5 MPa × 20 minutes, it was returned to an atmosphere of 23 ° C. and 50% RH, and the adhesive film after 1 hour was passed through a tensile tester at a speed of 300 mm / min in the 180 ° direction. The peel strength when peeled at is the adhesive strength of the adhesive film.

(Contamination test method)
After measuring the adhesive strength, the surface of the adherend (soda lime glass plate) is visually confirmed to determine the contamination caused by the adhesive layer. Contamination was evaluated according to the following criteria according to the contamination state of the adherend.
-Evaluation of contamination (O): The adhesive layer does not contaminate the adherend at all.
-Evaluation of contamination (△): The adhesive layer partially contaminates the adherend.
-Evaluation of contamination (x): The adhesive layer contaminates the adherend, and the adhesive layer is also transferred.

(Test method for penetration resistance to hydrofluoric acid)
The surface protective films for chemical polishing in Examples 1 to 6 and Comparative Examples 1 to 3 were bonded to the surface of a soda lime glass plate provided with a step having a height of 4 μm with a pressure roll, and then the temperature was 27 ° C. After immersing in a hydrofluoric acid aqueous solution having a concentration of 15% for 150 seconds, it was thoroughly washed with water. Then, after peeling off the surface protective film for chemical polishing, visually check the adherend surface of the glass substrate to which the surface protective film for chemical polishing was bonded, and check for corrosion of the soda lime glass plate due to the penetration of hydrofluoric acid. Confirm. The hydrofluoric acid permeation resistance was evaluated according to the following criteria according to the presence or absence and degree of corrosion of the glass substrate. ・ Evaluation of hydrofluoric acid permeation resistance (○): When there is no corrosion of the glass substrate .
-Evaluation of hydrofluoric acid permeation resistance (Δ): When hydrofluoric acid penetrates into the place where the surface protective film for chemical polishing was pasted, and a part of the glass substrate is corroded.
-Evaluation of hydrofluoric acid permeation resistance (x): When the hydrofluoric acid permeates the place where the surface protective film for chemical polishing was pasted and the glass substrate is corroded.

(Test method for erosion from the edge of the glass plate)
An ITO film was vapor-deposited on both surfaces of a glass plate for a touch panel sensor having a thickness of 0.4 mm and a rectangular shape with a length and width of 10 cm each. As shown in FIG. 1, four chemical polishing surface protective films of Example 1 cut to a size of 10 cm × 10 cm were prepared, and the width of 0.3 mm from the tip of one side of the glass plate 1 was used for chemical polishing. The laminate of Example 1 was bonded to the ITO film 5 on both surfaces of the glass plate 1 via the adhesive layer 3 of the surface protective film 4 for chemical polishing so that the surface protective film 4 protrudes. One was made. These laminates were immersed in a hydrofluoric acid aqueous solution having a temperature of 27 ° C. and a concentration of 15%, one laminate for 5 minutes, and the other laminate for 10 minutes, and then washed with water at room temperature for 5 minutes. Then, peel the surface protective film for chemical polishing on both sides from each laminate, and measure the maximum distance from one end of the glass plate in the range where the surface of the ITO film was discolored by permeation of hydrofluoric acid The erosion distance was used. Moreover, it replaced with the surface protective film for chemical polishing of Example 1, and produced the two laminated bodies of the comparative example 1 similarly except having used the surface protective film for chemical polishing of the comparative example 1, and eroded distance. Was measured. The test results are shown in Table 4.

In addition, the relationship between the erosion time and the erosion distance is shown in FIG.
2, when the surface protective film for chemical polishing of Example 1 was used, after being immersed in a hydrofluoric acid aqueous solution having a temperature of 27 ° C. and a concentration of 15%, the adherend surface of the glass plate as the adherend It can be confirmed that there is no permeation of hydrofluoric acid for at least 150 seconds in a portion having a distance of 80 μm or more from the end of the bonded surface of the chemical polishing surface protective film.

(Testing method for corrosiveness to ITO)
The adhesive layer of the surface protective film for chemical polishing is bonded to the surface of the ITO film, and the surface resistivity (SR1) of the ITO film after the passage of 85 ° C. and 90% RH × 1000 hours is measured. The surface resistivity (Ω / □) was measured using a resistivity meter Hiresta UP-HT450 (manufactured by Mitsubishi Chemical Analytech). The surface resistivity of the ITO film before the adhesive layer of the surface protective film for chemical polishing is attached to the initial value (SR0), and the change rate (%) of the surface resistivity is “100 × (SR1-SR0) / Calculated by “SR0”. Corrosivity to ITO was evaluated according to the following criteria according to the rate of change in surface resistivity.
-Corrosive evaluation (O): When the rate of change in surface resistivity is less than 2%.
Corrosion evaluation (△): When the rate of change of surface resistivity is 2% or more and less than 5%.
-Corrosive evaluation (x): When the rate of change in surface resistivity is 5% or more.

According to the test results shown in Table 2, the surface protective films for chemical polishing of Examples 1 to 6 have an appropriate adhesive strength, and each of contamination, hydrofluoric acid penetration resistance, and corrosivity to ITO. , Both were evaluated as good (◯).
Since the chemical polishing surface protective film of Comparative Example 1 had a large adhesive force, the contamination was somewhat inferior. Further, since the pressure-sensitive adhesive layer did not contain a silane coupling agent, water repellency was not added, and the hydrofluoric acid permeation resistance was poor.
Since the chemical polishing surface protective film of Comparative Example 2 had high adhesive strength, it was poor in contamination. Moreover, since the adhesive contains carboxylic acid, the corrosivity to ITO was inferior.
The chemical polishing surface protective film of Comparative Example 3 was poor in contamination because of its large adhesive force. Further, since the pressure-sensitive adhesive layer did not contain a silane coupling agent, water repellency was not added, and the hydrofluoric acid permeation resistance was poor.

  The present invention provides a surface protective film for chemical polishing that not only prevents the penetration of hydrofluoric acid, which is the main component of the chemical polishing liquid, between the glass substrate that is the adherend and the adhesive layer, but also does not cause adhesive residue. Therefore, industrial utility value is great.

DESCRIPTION OF SYMBOLS 1 ... Glass plate, 2 ... Resin film base material, 3 ... Adhesive layer, 4 ... Surface protection film for chemical polishing, 5 ... ITO film | membrane.

Claims (5)

A surface protective film for chemical polishing having an adhesive layer on one surface of a resin film substrate, wherein the resin film substrate has a thickness of 75 μm or more, and the adhesive layer comprises an acrylic copolymer and a silane cup It is formed by using an acrylic pressure-sensitive adhesive composition containing a ring agent and a crosslinking agent, and the acrylic copolymer comprises an alkyl (meth) acrylate monomer having a C1-C14 alkyl group, hydroxyl group Surface protection for chemical polishing comprising a copolymer obtained by copolymerizing at least one copolymerizable vinyl monomer selected from the group of a group-containing vinyl monomer and a nitrogen-containing vinyl monomer without containing a carboxyl group-containing monomer. The film is immersed in a hydrofluoric acid aqueous solution having a temperature of 27 ° C. and a concentration of 15% in a state where the film is bonded to the glass plate via the pressure-sensitive adhesive layer. Thereafter, the penetration of hydrofluoric acid into the portion of the adherend surface of the glass plate as the adherend from the end of the bonded surface of the chemical polishing surface protective film is at least 80 μm for at least 150 seconds. A surface protective film for chemical polishing, characterized by being free from rust.   The pressure-sensitive adhesive layer is laminated with a thickness of 10 to 35 μm, and when the thickness of the pressure-sensitive adhesive layer is 20 μm, the adhesive force to the glass plate is 0.1 to 1.5 N / 25 mm. The surface protective film for chemical polishing according to claim 1. The acrylic copolymer has (A) 80 to 95 parts by weight of at least one alkyl (meth) acrylate monomer having an alkyl group with C1 to C14, and (B) a hydroxyl group-containing vinyl monomer and nitrogen-containing compound. The pressure-sensitive adhesive layer comprises a copolymer obtained by copolymerizing 5 to 20 parts by weight of at least one copolymerizable vinyl monomer selected from the group of vinyl monomers without containing a carboxyl group-containing monomer, A pressure-sensitive adhesive comprising 100 parts by weight of the acrylic copolymer, 0.01 to 1 part by weight of (C) a silane coupling agent, and 0.01 to 10 parts by weight of (D) a crosslinking agent. The surface protective film for chemical polishing according to claim 1 or 2, wherein the surface protective film is formed using a composition.   The silane coupling agent has at least one organic functional group selected from the group consisting of an epoxy group, a (meth) acryloxy group, a mercapto group, and an amino group. A surface protective film for chemical polishing according to claim 1.   The surface protection film for chemical polishing according to claim 1, wherein the crosslinking agent is an isocyanate compound.

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