JP2017014308A - Adhesive tape, protective member and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide pressure sensitive adhesive double coated tape which is compatible with superior rework characteristics and air release property, and superior shock resistance and litter control property.SOLUTION: In adhesive tape having a structure that silicone pressure sensitive adhesive layer (A) is laminated on at least one side of a backing through easily adhesive layer, the silicone pressure sensitive adhesive layer (A) is a layer formed by using silicone pressure sensitive adhesive containing silicone compound (a1), aromatic hydrocarbon solvent (a2) and ketone solvent (a3).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive tape suitable for bonding, for example, an information display portion of a display and a member made of glass or the like.

  2. Description of the Related Art Conventionally, a surface protection member having a hard coat layer and an adhesive layer with a pencil hardness of about 2H is pasted on an information display portion of a display mounted on an electronic device for the purpose of preventing scratches on the surface of the display. There are many.

  However, when a strong impact is applied to the surface of the surface protection member by dropping the electronic device or the like, the surface of the hard coat layer may be damaged, resulting in poor appearance of the electronic device.

  For example, a surface protection member having a structure in which a double-sided pressure-sensitive adhesive tape is affixed to high-hardness tempered glass is known as the protection member that hardly causes damage.

  The surface protection member usually has a characteristic (rework) that can be re-applied for the purpose of correcting misalignment or the like when it is applied to the surface of the information display section of the display. Sex) is required. Therefore, excellent reworkability is also required for the double-sided pressure-sensitive adhesive tape used for the production.

  As the double-sided pressure-sensitive adhesive tape, for example, at least one of the pressure-sensitive adhesive layers on both sides of the support is made of a silicone-based pressure-sensitive adhesive, and the pressure-sensitive adhesive layer is treated with a release agent made of a polymer having a fluorine-containing side chain in the siloxane skeleton. There is known a double-sided pressure-sensitive adhesive tape characterized by being temporarily attached (see, for example, Patent Document 1).

  However, Patent Document 1 does not disclose that it is excellent in reworkability and air bleedability, nor does it disclose that it can be suitably used in applications that require these characteristics.

  The double-sided pressure-sensitive adhesive tape may cause peeling over time at the interface between the support and the silicone-based pressure-sensitive adhesive layer (A), particularly when exposed to a high temperature and high humidity environment for a certain period of time. In some cases, peeling occurred at the interface.

Japanese Patent Laid-Open No. 5-320592

  The problem to be solved by the present invention is that the base material and the silicone system that have excellent rework properties and air release properties and are the core even when exposed to a high temperature and high humidity environment for a certain period of time It is to provide an adhesive tape capable of preventing the interface with the pressure-sensitive adhesive layer (A) from peeling off with time.

  The present inventors are pressure-sensitive adhesive tapes having a structure in which a silicone pressure-sensitive adhesive layer (A) is laminated on at least one surface side of a substrate via an easy-adhesion layer, and the silicone pressure-sensitive adhesive layer (A) is a layer formed using a silicone-based pressure-sensitive adhesive containing a silicone-based compound (a1), an aromatic hydrocarbon-based solvent (a2), and a ketone-based solvent (a3). It has been found that the above problems can be solved by the adhesive tape.

  The pressure-sensitive adhesive tape of the present invention has excellent reworkability and air release property, and even when it is exposed to a high temperature and high humidity environment for a certain period of time, the core and the silicone pressure-sensitive adhesive layer It is possible to prevent peeling of the interface with (A) over time.

  Therefore, the pressure-sensitive adhesive tape of the present invention can be suitably used for adhesion between, for example, an information display part of a display and a member made of glass or resin. Moreover, the adhesive tape of this invention can be used for manufacture of the protection member stuck on the information display part of the said display.

It is a figure which shows an example of a structure of the protection member of this invention.

  The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a structure in which a silicone-based pressure-sensitive adhesive layer (A) is laminated on at least one surface side of a substrate via an easy-adhesion layer, the silicone-based pressure-sensitive adhesive The layer (A) is a layer formed by using a silicone-based pressure-sensitive adhesive containing a silicone-based compound (a1), an aromatic hydrocarbon-based solvent (a2), and a ketone-based solvent (a3). To do.

  As the silicone-based pressure-sensitive adhesive layer (A) constituting the pressure-sensitive adhesive tape of the present invention, a 25 μm-thick polyethylene terephthalate film is attached to the silicone-based pressure-sensitive adhesive layer (A), and the polyethylene terephthalate film is used as the silicone-based pressure-sensitive adhesive. It is preferable to use one having a tensile strength measured by pulling in the direction of 180 ° with respect to the surface of the layer (A) in the range of 0.01 N / 25 mm to 0.1 N / 25 mm, and 0.02 N / It is more preferable to use the one in the range of 25 mm to 0.08 N / 25 mm, and the use of the one in the range of 0.04 N / 25 mm to 0.07 N / 25 mm is, for example, for the information display part of the display In order to obtain a pressure-sensitive adhesive tape that has both excellent reworkability and air release properties, and excellent impact resistance, etc. Further preferred.

  In addition, the said tensile strength points out the value measured with the following method. The pressure-sensitive adhesive tape cut to a width of 50 mm under an environment of 23 ° C. and 50% RH was placed so that the silicone pressure-sensitive adhesive layer (A) was on the upper surface, and the silicone pressure-sensitive adhesive layer (A) was After placing “S-25” (polyester film thickness 25 μm, manufactured by Unitika Co., Ltd.) cut to a width of 25 mm, the upper surface thereof was pressure-applied by reciprocating a 2 kg roller, and then 23 ° C. And left in a 50% RH environment for 1 hour.

  Thereafter, using a tensile tester (Tensilon RTA-100, manufactured by A & D Co., Ltd.) in a 23 ° C. and 50% RH environment, the “S-25” was changed to the silicone-based pressure-sensitive adhesive under the conditions of a tensile speed of 300 mm / min. It is pulled in the direction of 180 ° with respect to the surface of the layer (A), and the adhesive strength when it is peeled is measured. In addition, the said measurement is performed in the state which stuck the acrylic adhesive layer (B) and aluminum plate which the said adhesive tape may have using the double-sided tape "# 8625UJ" by DIC Corporation. Is preferred.

  The silicone pressure-sensitive adhesive layer (A) preferably has a thickness in the range of 5 μm to 100 μm, more preferably in the range of 15 μm to 50 μm, and further preferably in the range of 20 μm to 40 μm. Preferably, the thickness is in the range of 25 μm to 35 μm, for example, it is possible to achieve both excellent reworkability and air bleedability for the information display portion of the display, and the above-mentioned due to impact such as dropping. It can provide excellent impact resistance at a level that does not cause peeling between the information display part and the silicone-based pressure-sensitive adhesive layer (A), and excellent adhesion to a non-smooth surface. Even in such a case, it is particularly preferable for obtaining a pressure-sensitive adhesive tape that can prevent the interface between the substrate and the silicone-based pressure-sensitive adhesive layer (A) from peeling with time.

  The silicone pressure-sensitive adhesive layer (A) was formed by using a silicone pressure-sensitive adhesive containing a silicone compound (a1), an aromatic hydrocarbon solvent (a2), and a ketone solvent (a3). Use layers.

  As a silicone type compound (a1) which comprises the said silicone type adhesive, what contains what is generally called a gum component and a resin component can be used.

  As said gum component, what mainly becomes a binder component of an adhesive can be used, for example, polyorganosilicone etc. can be used. As the polyorganosilicone, a peroxide curable type and an addition curable type are known, and both can be used, but the silicone pressure-sensitive adhesive layer (A) having a tensile strength in the predetermined range is used. As a result, it is preferable to use a material containing an addition-curable polyorganosilicone in order to express even better reworkability and air release properties and excellent impact resistance.

As the addition-curable polyorganosilicone, for example, a polyorganosiloxane having a structure (—Si—CH═CH ₂ group) in which a polymerizable unsaturated double bond is bonded to a silicon atom can be used.

  Moreover, as said addition-curable polyorganosilicone, what has either of the structures (1)-(4) mentioned later can be used, and what has the following structures (1) and (4) is used. It is preferable to do.

  Specific examples of the addition-curable polyorganosilicone include addition-curable dimethylpolysiloxane, addition-curable dimethylphenylpolysiloxane, addition-curable polyethylphenylsiloxane, and addition-curable polymethylphenylsiloxane. it can.

  As the addition-curable polyorganosilicone, it is possible to form a silicone-based pressure-sensitive adhesive layer (A) having a tensile strength within the predetermined range by using one having a phenyl group. As a result, reworkability and It is preferable because the air release property can be further improved. Further, as the addition-curable polyorganosilicone, the use of addition-curable dimethylpolysiloxane can form the silicone-based pressure-sensitive adhesive layer (A) having the predetermined range of tensile strength, and as a result, This is preferable because it is easy to achieve both excellent air detachability and good followability to the adherend.

  As the addition-curable polyorganosilicone, those having a weight average molecular weight of 50,000 to 1,000,000 are preferably used, and those having a weight average molecular weight of 100,000 to 500,000 are more preferable. It is more preferable to use a material having a weight average molecular weight of 200,000 to 350,000 in order to obtain a pressure-sensitive adhesive tape having particularly excellent air release properties.

  Moreover, as said silicone type adhesive, what contains the said resin component can be used as needed other than an above described component.

  The resin component can be appropriately selected from conventionally known ones, but a polyorganosilicone having a relatively low molecular weight is preferably used, and an addition-curable polyorganosilicone is more preferably used.

  As the polyorganosilicone usable as the resin component, for example, those having at least one selected from the group consisting of the following structures (1) to (4) can be used, and the structures (1) and (2 ) Is preferably used. The ratio (molar ratio) between the structure (1) and the structure (2) is preferably structure (1): structure (2) = 0.4: 1 to 1.4: 1, 0.6: It is more preferable to use one that is 1 to 1.2: 1.

(R represents a monovalent hydrocarbon group or a hydroxyl group.)

  As the polyorganosilicone as the resin component, among those exemplified as the gum component, those having a weight average molecular weight of preferably 100 to 10,000, more preferably 300 to 8000, and still more preferably 3000 to 6000 are used. Can do.

  The mass ratio of the polyorganosilicone that is the gum component and the polyorganosilicone that is the resin component is preferably 100: 0 to 65:35, more preferably 95: 5 to 70:30, It is easy to form the silicone-based pressure-sensitive adhesive layer (A) having the tensile strength in the predetermined range, and it is more excellent in air release property, rework property, and impact resistance. This is particularly preferable because it is highly compatible with each other.

  In addition, the resin component and the gum component may be premixed. Examples of the resin, gum component and solvent premixed are “X-40-3306”, “X-40-3229”, “X-40-3323” (manufactured by Shin-Etsu Chemical Co., Ltd.). Can be used.

  In addition, as the silicone-based pressure-sensitive adhesive, it is possible to use an aromatic hydrocarbon solvent (a2) and a ketone-based solvent (a3) as a solvent in combination so that the adhesion between the base material and the silicone-based pressure-sensitive adhesive layer (A) is increased. Can be further improved, and peeling over time, particularly peeling that is likely to occur when placed in a high temperature environment, can be effectively suppressed.

  As the aromatic hydrocarbon solvent (a2), for example, toluene, xylene and the like can be used, and among them, use of toluene improves compatibility with the silicone compound (a1) and is smooth. It is preferable for forming the silicone-based pressure-sensitive adhesive layer (A).

  Further, as the ketone solvent (a3), for example, methyl ethyl ketone, acetone, methyl isobutyl ketone and the like can be used, and among them, the use of methyl ethyl ketone is preferable for the base material and the silicone pressure-sensitive adhesive layer (A). It is preferable for preventing the peeling of the film over time.

  The aromatic hydrocarbon solvent (a2) is preferably used in the range of 10% by mass to 500% by mass with respect to the total solid content (100% by mass) of the silicone compound (a1), and 100% by mass. It is more preferable to use in the range of% to 400% by mass when forming a smooth silicone pressure-sensitive adhesive layer.

  The ketone solvent (a3) is preferably used in a range of 10% by mass to 150% by mass, and in a range of 50% by mass to 300% by mass with respect to the total amount of the solid content of the silicone compound (a1). The use further improves the adhesion between the substrate and the silicone-based pressure-sensitive adhesive layer (A), and effectively suppresses the peeling that occurs over time, especially when it is placed in a high-temperature environment. It is more preferable because it can be performed.

  The mass ratio of the aromatic hydrocarbon solvent (a2) and the ketone solvent (a3) [the aromatic hydrocarbon solvent (a2) / the ketone solvent (a3)] is 50/50 to 90 / A range of 10 is preferable, and a range of 60/40 to 80/20 is more preferable in forming a pressure-sensitive adhesive layer that is smooth and excellent in adhesion to a substrate.

  Moreover, as said silicone type adhesive, what contains a crosslinking agent, a metal catalyst, etc. besides the above-mentioned component can be used.

  Moreover, as a crosslinking agent which may be contained in the said silicone adhesive, what has a structure which can react with the functional group which the silicone type compound (a1) equivalent to the said gum component or resin component has is used. For example, a crosslinking agent containing a siloxane having a structure in which a hydrogen atom is bonded to a silicon atom (—Si—H group) can be used. Specifically, a polyorganohydrodienesiloxane having at least two hydrogen atoms bonded to a silicon atom in the molecular weight can be used, and in particular, a structure in which a hydrogen atom is bonded to a silicon atom (—Si—H group). It is preferable to use hydrogen dimethylpolysiloxane having both at the ends of the molecule.

  Moreover, as a metal catalyst that may be contained in the silicone-based pressure-sensitive adhesive, it is preferable to use, for example, an organometallic catalyst belonging to Group 10 of the periodic table of elements, and specifically, a platinum-based catalyst may be used. It is more preferable because it is excellent in the reaction promoting effect.

  As the crosslinking agent and the catalyst, those previously mixed may be used, or those in which they form a complex may be used. Specifically, it is more preferable to use a complex of platinum (0) and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane or a xylene solution thereof.

  As the silicone pressure-sensitive adhesive layer (A) formed using the silicone-based pressure-sensitive adhesive, it is preferable to use a layer having a gel fraction of 85% by mass to 99% by mass, and 86% by mass to 97% by mass. %, More preferably 87% to 92% by weight, for example, excellent reworkability and air detachability for the information display portion of the display, and excellent impact resistance. It is further preferable for obtaining a pressure-sensitive adhesive tape having both properties.

The gel fraction is applied to one side of a polyester film “A4300 # 38” manufactured by Toyobo Co., Ltd., which is a base material, using a lip coater so that the thickness after drying is 30 μm. Then, after drying at 140 ° C. for 2 minutes, a single-sided adhesive tape is produced by curing at 40 ° C. for 48 hours, and refers to the mass calculated before and after immersing it in toluene and the value calculated by the following equation.
Gel fraction (mass%) = {(mass of silicone-based adhesive layer (A) after immersing single-sided adhesive tape in toluene) / (silicone-based adhesive layer before immersing single-sided adhesive tape in toluene (A ) Mass)} × 100

  Moreover, as a silicone type adhesive layer (A) formed using the said silicone type adhesive, it is preferable that the total light transmittance (JIS K7361) in the visible light is 90% or more, and is 92% or more. More preferably, it is more preferably 93% or more. Moreover, as said silicone type adhesive layer (A), it is preferable to use that whose haze (JIS K7136) in the visible light is 2% or less, and it is more preferable to use what is 1% or less. Further, it is more preferable to use one that is 0.8% or less.

(Base material)
Although it does not specifically limit as a base material which can be used for manufacture of the said adhesive tape, For example, a polyethylene terephthalate, a polybutylene terephthalate, a polyethylene naphthalate, a polyethylene film, a polypropylene film, a cellophane, a diacetyl cellulose film, a triacetyl cellulose film, acetyl Cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether Sulfone film, polyetherimide film, polyimide film, fluorine resin film, Nylon film, it is possible to use an acrylic resin film or the like. Of these, polyethylene terephthalate is preferably used as the substrate.

  The substrate preferably has a thickness in the range of 2 μm to 100 μm, more preferably a thickness in the range of 16 μm to 75 μm, and a thickness in the range of 20 μm to 50 μm. It is more preferable to use a material having a thickness in the range of 20 μm to 45 μm.

  The adhesive tape of this invention has an easily bonding layer between the said base material and the said silicone type adhesive layer (A). The easy-adhesion layer is usually formed on at least one surface of the substrate.

  As the easy-adhesion layer, it is preferable to use a layer capable of improving the adhesion between the silicone-based pressure-sensitive adhesive layer (A) and the substrate, and for example, an easy-adhesion layer containing polyester is more preferable. preferable.

  In the pressure-sensitive adhesive tape of the present invention, the adhesiveness between the base material and the silicone pressure-sensitive adhesive layer is not improved simply by providing the easy-adhesion layer, but the formation of the silicone-based pressure-sensitive adhesive layer (A). It is presumed that the ketone solvent (a3) contained in the silicone-based pressure-sensitive adhesive used in the above exhibits the effect of the present invention by swelling the easy-adhesion layer.

  The easy-adhesion layer preferably has a thickness in the range of 0.01 μm to 5 μm, and more preferably has a thickness in the range of 0.05 μm to 1 μm.

  As a specific embodiment of the pressure-sensitive adhesive tape of the present invention, as described above, the pressure-sensitive adhesive tape having the silicone-based pressure-sensitive adhesive layer (A) on one surface side of the substrate via an easy-adhesive layer, Examples thereof include a pressure-sensitive adhesive tape having a silicone-based pressure-sensitive adhesive layer (A) on both surface sides via an easy-adhesion layer. On the other hand, when using the pressure-sensitive adhesive tape of the present invention as a member (protective member) that protects the surface of an information display unit such as a display, for example, on one surface side of the substrate, an easy-adhesive layer is interposed, It has the said silicone type adhesive layer (A), and uses what consists of an adhesive tape which has an acrylic adhesive layer (B) in the other surface side of the said base material directly or through an easily bonding layer. It is preferable.

  As said acrylic adhesive layer (B), a 25-micrometer-thick polyethylene terephthalate film is stuck to the said acrylic adhesive layer (B), and the said polyethylene terephthalate film is put on the surface of the said acrylic adhesive layer (B). On the other hand, it is preferable to use a material having a tensile strength measured by pulling in the direction of 180 ° within a range of 5 N / 25 mm to 28 N / 25 mm, and a material having a range of 10 N / 25 mm to 25 N / 25 mm. It is more preferable to use a material having a range of 13 N / 25 mm to 20 N / 25 mm, for example, for a member made of glass or resin such as tempered glass, and more excellent reworkability at the initial stage of application, Further, it is more preferable because the anti-scattering property can be highly compatible.

  In addition, the said tensile strength points out the value measured with the following method. The pressure-sensitive adhesive tape cut to a width of 50 mm under an environment of 23 ° C. and 50% RH is placed so that the acrylic pressure-sensitive adhesive layer (B) is the upper surface, and the acrylic pressure-sensitive adhesive layer (B) After placing “S-25” (polyester film thickness 25 μm, manufactured by Unitika Co., Ltd.) cut to a width of 25 mm, the upper surface thereof was pressure-applied by reciprocating a 2 kg roller, and then 23 ° C. And left in a 50% RH environment for 1 hour.

  Thereafter, using a tensile tester (Tensilon RTA-100, manufactured by A & D) at 23 ° C. and 50% RH, the “S-25” was converted to the acrylic pressure-sensitive adhesive under the conditions of a tensile speed of 300 mm / min. It is pulled in the direction of 180 ° with respect to the surface of the layer (B), and the adhesive strength when it is peeled is measured. In addition, the said measurement is performed in the state which stuck the silicone type adhesive layer (A) and aluminum plate which comprise the said adhesive tape using the double-sided tape "# 8625HPW" by DIC Corporation.

  The acrylic pressure-sensitive adhesive layer (B) preferably has a thickness in the range of 5 μm to 100 μm, more preferably in the range of 10 μm to 50 μm, and further preferably in the range of 15 μm to 30 μm. Preferably, having a thickness in the range of 20 μm to 25 μm is highly compatible with reworkability and anti-scattering properties at the initial stage of application for a member made of glass or resin such as tempered glass, for example. Is particularly preferable. In addition, by employing the acrylic pressure-sensitive adhesive layer (B) having the above thickness, an interface between the acrylic pressure-sensitive adhesive layer (B) and a member made of glass or resin such as tempered glass when the protective member is manufactured. It is possible to make it difficult for air bubbles to be caught in.

  The acrylic pressure-sensitive adhesive layer (B) can be formed by using an acrylic pressure-sensitive adhesive.

  As said acrylic adhesive, what contains an acrylic polymer and a crosslinking agent, tackifying resin, etc. as needed can be used, for example.

  The acrylic polymer can be produced by polymerizing a monomer containing a (meth) acrylic monomer.

  Examples of the monomer include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, and isooctyl acrylate. 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate , Cyclohexyl methacrylate, n-octyl methacrylate, isooctyl meta (Meth) acrylic acid esters having an alkyl group having 2 to 14 carbon atoms such as relate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, lauryl methacrylate, etc. can be used alone or in combination of two or more. .

  Among them, it is preferable to use (meth) acrylic acid alkyl ester having an alkyl group having 4 to 9 carbon atoms as the monomer, and alkyl acrylate having alkyl having 4 to 9 carbon atoms. It is more preferable to use an ester, and the use of n-butyl acrylate and 2-ethylhexyl acrylate can form an acrylic pressure-sensitive adhesive layer (B) having a tensile strength within the predetermined range. It is particularly preferable for a member made of a resin because it can achieve a high level of reworkability at the initial stage of application and excellent anti-scattering properties.

  The (meth) acrylic acid ester having an alkyl group having 2 to 14 carbon atoms is used in the range of 80% by mass to 99% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. It is preferable that the acrylic pressure-sensitive adhesive layer (B) having a tensile strength in the predetermined range can be formed by using in the range of 85% by mass to 96% by mass, and as a result, a member made of glass or resin. On the other hand, it is more preferable because the reworkability more excellent in the initial stage of application and the excellent antiscattering property can be achieved at a high level.

  Further, as the monomer, in addition to those described above, a monomer having a functional group such as a hydroxyl group, a carboxyl group, or an amino group can be used.

  Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. As the monomer having a carboxyl group, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, crotonic acid, fumaric acid, carboxypropyl acrylate maleate and the like can be used. As the monomer having an amino group, for example, dimethylaminoethylacrylamide, N-vinylpyrrolidone, acrylonitrile, N-vinylcaprolactam, acrylamide, styrene, vinyl acetate, N-methylol acrylamide, glycidyl methacrylate and the like can be used. .

Especially, the monomer which has the said hydroxyl group, and the monomer which has a carboxyl group can be used when forming the acrylic adhesive layer (B) provided with the tensile strength in the above-mentioned predetermined range. preferable.
As the monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate can be preferably used, and as the monomer having a carboxyl group, acrylic acid or methacrylic acid can be preferably used.

  The monomer having a functional group such as a hydroxyl group, a carboxyl group, or an amino group is used in the range of 1% by mass to 20% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. It is preferable to use in the range of 4% by mass to 15% by mass.

  The monomer having a hydroxyl group is preferably used in a range of 0.1% by mass to 15% by mass with respect to the total amount of monomers used for the production of the acrylic polymer, and 0.1% by mass. It is more preferable to use in the range of 5% to 5% by mass. The monomer having a carboxyl group is preferably used in the range of 0.1% by mass to 15% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. It is more preferable to use in the range of 10% by mass to 10% by mass.

  The acrylic polymer (B) can be produced by polymerizing the monomer by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. Manufacture by law is good for improving the production efficiency of adhesive tape and reducing its production cost.

  As the acrylic polymer obtained by the above method, those having a weight average molecular weight in the range of 400,000 to 1,500,000 are preferably used, and those having a weight average molecular weight in the range of 600,000 to 1,200,000 are used. It is preferable to do.

The weight average molecular weight of the acrylic polymer can be measured by gel permeation chromatography (GPC). More specifically, as a GPC measurement device, “SC8020” manufactured by Tosoh Corporation can be used to measure and obtain the following GPC measurement conditions based on polystyrene conversion values.
(GPC measurement conditions)
Sample concentration: 0.5 parts by mass (tetrahydrofuran solution)
Sample injection volume: 100 μL
・ Eluent: Tetrahydrofuran (THF)
・ Flow rate: 1.0 mL / min
Column temperature (measurement temperature): 40 ° C
Column: “TSKgel GMHHR-H” manufactured by Tosoh Corporation
・ Detector: Differential refraction

  As the acrylic pressure-sensitive adhesive that can be used for forming the acrylic pressure-sensitive adhesive layer (B), it is possible to use a material containing a crosslinking agent in addition to the acrylic polymer. ) Is more preferable for forming an acrylic pressure-sensitive adhesive layer (B) having a three-dimensional cross-linking structure and having both excellent reworkability and anti-scattering properties.

  As said acrylic adhesive layer (B), it is preferable to use what the gel fraction is 10 mass%-70 mass%, and using what is 30 mass%-60 mass%, This is preferable because it is possible to achieve both excellent reworkability and scattering prevention.

The gel fraction is applied to one side of a polyester film “A4300 # 38” manufactured by Toyobo Co., Ltd., which is a base material, using a lip coater so that the thickness after drying is 30 μm. Then, after drying at 140 ° C. for 2 minutes, a single-sided adhesive tape is produced by curing at 40 ° C. for 48 hours, and refers to the mass calculated before and after immersing it in toluene and the value calculated by the following equation.
Gel fraction (mass%) = {(mass of acrylic adhesive layer (B) after immersing single-sided adhesive tape in toluene) / (acrylic adhesive layer (B) before immersing single-sided adhesive tape in toluene ) Mass)} × 100

  In addition, as the crosslinking agent that can be used for the acrylic pressure-sensitive adhesive, for example, the acrylic polymer has an isocyanate crosslinking agent, an epoxy crosslinking agent, a chelate crosslinking agent, an aziridine crosslinking agent, and the like. It can be selected and used according to the type of the crosslinkable functional group that may be used, and it is preferable to use an epoxy-based crosslinking agent in order to prevent discoloration (yellowing) of the adhesive tape over time.

  The content of the cross-linking agent can be appropriately selected and used so that the acrylic pressure-sensitive adhesive layer (B) having the preferred gel fraction can be formed.

  In order to further improve the adhesive strength of the pressure-sensitive adhesive tape, the acrylic pressure-sensitive adhesive may contain a tackifier resin.

  As the tackifying resin, rosin resin, terpene resin, aliphatic (C5) or aromatic (C9) petroleum resin, styrene resin, phenol resin, xylene resin, methacrylic resin, etc. are used. Among them, it is preferable to use an acrylic tackifying resin because it is possible to achieve further excellent anti-scattering properties, transparency and yellowing resistance.

  As the acrylic tackifying resin, those having a lower molecular weight than the acrylic polymer can be used, and in order to achieve further excellent anti-scattering properties, transparency and yellowing resistance, preferably 100 Those having a weight average molecular weight of 100,000 to 100,000, more preferably those having a weight average molecular weight of 1000 to 50,000, and still more preferably those having a weight average molecular weight of 3000 to 30,000 can be used.

  As said acrylic tackifying resin, what is obtained by superposing | polymerizing an acrylic monomer can be used. As the acrylic monomer, a (meth) acrylic acid ester having an alkyl group having 1 to 4 carbon atoms is preferably used. Examples of the (meth) acrylic acid ester having an alkyl group having 1 to 4 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n -Butyl (meth) acrylate etc. can be used individually or in combination of 2 or more types.

  Especially, as (meth) acrylic acid ester which has the said C1-C4 alkyl group, since high adhesiveness can be provided with respect to the member which consists of glass especially, it is preferable.

  The (meth) acrylic acid ester having an alkyl group having 1 to 4 carbon atoms is in the range of 80% by mass to 99% by mass with respect to the total amount of monomers used for the production of the acrylic tackifying resin. It is preferable to use it, and it is more preferable to use it in the range of 85% by mass to 96% by mass because high adhesiveness can be imparted to a member made of glass.

  As a monomer used for the production of the acrylic tackifying resin, a monomer having a functional group such as a hydroxyl group, a carboxyl group, or an amino group can be used. Examples of the monomer include monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate, acrylic acid, methacrylic acid, and maleic acid. Monomers having a carboxyl group such as acid, maleic anhydride, itaconic acid, crotonic acid, fumaric acid, maleic anhydride carboxypropyl acrylate, dimethylaminoethylacrylamide, N-vinylpyrrolidone, acrylonitrile, N-vinylcaprolactam, acrylamide, Monomers having amino groups such as dimethylaminoethyl (meth) acrylate, styrene, vinyl acetate, N-methylol acrylate, glycidyl methacrylate, etc. can be used alone or in combination of two or more.

  Among them, it is preferable to use a monomer having an amino group because it can be suitably compatible with the acrylic polymer and can form an acrylic pressure-sensitive adhesive layer (B) having excellent optical properties. As the monomer having an amino group, dimethylaminoethyl (meth) acrylate can be preferably used.

  The monomer having a functional group such as a hydroxyl group, a carboxyl group, or an amino group is in a range of 0.01% by mass to 15% by mass with respect to the total amount of monomers used for the production of the acrylic tackifying resin. Is preferably used.

  The acrylic tackifying resin is preferably used in a range of 5 to 50 parts by mass, more preferably in a range of 7 to 30 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is particularly preferable to use in the range of 9 to 23 parts by mass.

  Moreover, as an acrylic adhesive layer (B) formed using the said acrylic adhesive, it is preferable that the total light transmittance (JIS K7361) in the visible light is 90% or more, and is 92% or more. More preferably, it is more preferably 92.5% or more. Moreover, as said acrylic adhesive layer (B), it is preferable to use the thing whose haze (JIS K7136) in the visible light is 2% or less, and it is more preferable to use what is 1% or less. Further, it is more preferable to use one that is 0.8% or less.

  Moreover, as a double-sided adhesive tape that can be used for the production of the protective member of the present invention, in addition to the above-mentioned reworkability and air release property, even when a strong impact is applied, the information display portion of the display is protected. There are cases where a level of impact resistance that does not easily cause peeling from the member or a characteristic that prevents the glass from scattering when the glass constituting the protective member breaks (scattering prevention) may be required.

  Although the impact resistance may be improved to some extent by providing a pressure-sensitive adhesive layer having strong adhesiveness, for example, the strong adhesive pressure-sensitive adhesive layer causes a slight decrease in the air bleeding property and reworkability. there is a possibility. In the present invention, by using the preferred acrylic pressure-sensitive adhesive layer (B) as described above, it is possible to achieve both excellent air release properties and rework properties, and excellent impact resistance and scattering prevention properties. It is.

(Production method)
The pressure-sensitive adhesive tape of the present invention is prepared, for example, by preparing an adhesive layer formed on at least one surface of the base material in advance, and applying the silicone-based adhesive to the surface of the easy-adhesion layer, followed by drying, etc. Forming a silicone-based pressure-sensitive adhesive layer (A) and applying a release liner to the silicone-based pressure-sensitive adhesive layer (A) as necessary to produce a single-sided pressure-sensitive adhesive tape; The step of forming the acrylic pressure-sensitive adhesive layer (B) by applying and drying the acrylic pressure-sensitive adhesive on a mold liner, and the other surface side of the base material constituting the single-sided pressure-sensitive adhesive tape, It is preferable to manufacture by passing through a process of transferring the acrylic pressure-sensitive adhesive layer (B).

  Examples of a method for applying the silicone-based pressure-sensitive adhesive to the easy-adhesion layer of the base material include a method for applying using a precision coating machine such as a lip coater. Drying when forming the silicone-based pressure-sensitive adhesive layer (A) is preferably performed at 110 ° C. to 150 ° C. for 30 seconds to 3 minutes.

  Moreover, as a method of coating the said acrylic adhesive to a release liner etc., the method of coating using precision coating machines, such as a lip coater, is mentioned, for example. Drying when forming the acrylic pressure-sensitive adhesive layer (B) is preferably performed at 80 ° C. to 120 ° C. for 30 seconds to 3 minutes.

(Release liner)
The pressure-sensitive adhesive tape of the present invention preferably has a release liner laminated on the pressure-sensitive adhesive layer.

  As a release liner that may be laminated on the silicone-based pressure-sensitive adhesive layer (A), for example, a resin film such as polyethylene, polypropylene (orientated polypropylene (OPP), cast polypropylene (CPP)), polyethylene terephthalate, or the like is used as it is. Can do.

  On the other hand, as a release liner that may be laminated on the acrylic pressure-sensitive adhesive layer (B), among resin films such as polyethylene, polypropylene (orientated polypropylene (OPP), cast polypropylene (CPP)), polyethylene terephthalate, silicone, etc. What was peel-processed with the system resin etc. can be used.

  The pressure-sensitive adhesive tape of the present invention obtained by the above method preferably has a thickness of 50 μm to 200 μm, and more preferably has a thickness of 60 μm to 150 μm.

  The pressure-sensitive adhesive tape of the present invention can be used exclusively for adhesion between an information display portion of a display and a member made of glass or resin. At that time, the silicone pressure-sensitive adhesive layer (A) constituting the pressure-sensitive adhesive tape is affixed to the surface of the information display unit, and the acrylic pressure-sensitive adhesive layer (B) is a surface of a member made of glass or resin. It is preferable that the adhesive tape is affixed to the adhesive tape in order to obtain an adhesive tape excellent in reworkability and air release property.

(Information display part of the display)
The information display unit refers exclusively to a part capable of displaying images, videos, and the like, and examples thereof include the surface of a liquid crystal panel and the surface of an organic EL panel. The outermost surface of the information display unit (the surface to which the silicone-based pressure-sensitive adhesive layer (A) of the adhesive tape is attached) may be a surface made of resin or a surface made of glass. Such a surface is preferable because it is excellent in reworkability with the silicone-based pressure-sensitive adhesive layer (A), air release property, and impact resistance.

(Member made of glass or resin)
Examples of the member include tempered glass. The tempered glass is a glass having a strength higher than that of a normal plate glass in which a compressive stress layer is provided on the glass surface. The tempered glass includes physically tempered glass and chemically tempered glass, but it is preferable to use chemically tempered glass.

  Specifically, chemically strengthened glass is glass in which alkali ions having a large ion radius are introduced into the surface of the glass by ion exchange at a temperature lower than the melting point of the glass. Commercial products include Corning Gorilla Glass.

  As the member made of glass such as the tempered glass, it is preferable to use a member having a thickness of 0.1 mm to 0.6 mm. If it is used for surface protection of a mobile device, 0.2 mm to 0.00 mm. It is more preferable to use a thickness of 5 mm.

  As the member made of glass such as the tempered glass, a member having a surface hardness of 5H or more is preferably used, and a member having 9H or more is more preferably used.

  Moreover, as a member consisting of resin, the film or sheet-like thing which consists of resin, such as polyester, such as polyethylene terephthalate, and polyurethane, can be used, for example.

(Protective member)
As a protective member, what has the structure by which the member which consists of glass or resin was previously affixed on the surface of the said acrylic adhesive layer (B) which the said adhesive tape has is mentioned. Bonding of the adhesive tape and a member made of glass or resin such as tempered glass can usually be performed using a roller or the like. As the protective member, one obtained by previously pasting a member made of glass or resin on the surface of the acrylic pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive tape is subjected to autoclave treatment (for example, 40 ° C. to 60 ° C. and 0.1 MPa). It is preferable to use a material that has been allowed to stand for 5 minutes to 60 minutes in an environment of ˜1 MPa, since the scattering prevention property can be further improved.

  The protective member can be easily affixed to the surface of the information display unit constituting the display by hand without using a roller or the like. If it is the protection member of the present invention, bubbles at the surface between the silicone pressure-sensitive adhesive layer (A) and the surface of the information display portion constituting the display are difficult to enter during the pasting. Even in such a case, the air bubbles can be quickly removed (excellent in air removal properties), so that appearance deterioration caused by the bubbles can be prevented.

  The protective member is less likely to be scratched and has higher transparency than a conventional protective resin film with a hard coat having a surface hardness of about 2H, and thus has a good appearance when attached to a display body.

  Examples and comparative examples will be specifically described below.

[Preparation of silicone adhesive]
(Silicone adhesive A)
90 parts by mass of addition-curable dimethylphenylpolysiloxane having a weight average molecular weight of 280,000 as a gum component, 10 parts by mass of dimethylphenylpolysiloxane having a weight average molecular weight of 550 as a resin component, 200 parts by mass of toluene, and 33 parts by mass of methyl ethyl ketone 0.666 parts by mass of the catalyst “CAT-PL-50T” (Shin-Etsu Chemical Co., Ltd., reaction product of chloroplatinic acid and vinyl group-containing siloxane) is added to the product, and the mixture is stirred for 15 minutes using a stirrer. To obtain a silicone-based pressure-sensitive adhesive A.

(Silicone adhesive B)
A mixture of 85 parts by mass of addition-curable dimethylpolysiloxane having a weight average molecular weight of 280,000 as a gum component, 15 parts by mass of dimethylpolysiloxane having a weight average molecular weight of 4500 as a resin component, 200 parts by mass of toluene, and 33 parts by mass of methyl ethyl ketone The catalyst "CAT-PL-50T" (manufactured by Shin-Etsu Chemical Co., Ltd., reaction product of chloroplatinic acid and vinyl group-containing siloxane) 0.833 parts by mass was added to the silicone by stirring for 15 minutes using a stirrer. System adhesive B was obtained.

(Silicone adhesive C)
To a mixture of 90 parts by mass of addition-curing dimethylphenylpolysiloxane having a weight average molecular weight of 280,000 as a gum component, 10 parts by mass of dimethylphenylpolysiloxane having a weight average molecular weight of 550 as a resin component, and 233 parts by mass of toluene, CAT-PL-50T "(manufactured by Shin-Etsu Chemical Co., Ltd., reaction product of chloroplatinic acid and vinyl group-containing siloxane) is added in an amount of 0.666 parts by mass, and the mixture is stirred for 15 minutes using a stirrer. Got.

(Silicone-based adhesive D)
A mixture of 90 parts by mass of addition-curable dimethylphenylpolysiloxane having a weight average molecular weight of 280,000 as a gum component, 10 parts by mass of dimethylphenylpolysiloxane having a weight average molecular weight of 550 as a resin component, and 233 parts by mass of methyl ethyl ketone, CAT-PL-50T "(manufactured by Shin-Etsu Chemical Co., Ltd., reaction product of chloroplatinic acid and vinyl group-containing siloxane) is added in an amount of 0.666 parts by mass, and the mixture is stirred for 15 minutes using a stirrer, thereby causing silicone-based adhesive D Got.

(Preparation of acrylic adhesive)
(Acrylic adhesive a)
<Preparation of acrylic polymer (1)>
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 95.5 parts by mass of n-butyl acrylate, 0.5 parts by mass of 2-hydroxyethyl acrylate, 4.0 parts by mass of acrylic acid Part, 2,2'-azobisisobutylnitrile 0.2 part as a polymerization initiator is dissolved in 100 parts by mass of ethyl acetate, and after substitution with nitrogen, polymerization is carried out at 80 ° C. for 8 hours to obtain an acrylic resin having a weight average molecular weight of 800,000. A polymer (1) solution was obtained.

<Preparation of acrylic tackifying resin>
In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 95.0 parts by mass of methyl methacrylate, 5.0 parts by mass of dimethylaminoethyl methacrylate, 2,2′- as a polymerization initiator An acrylic tackifying resin having a weight average molecular weight of 20,000 was obtained by dissolving 1.0 part by mass of azobisisobutylnitrile in 100 parts by mass of ethyl acetate, followed by nitrogen substitution and polymerizing at 80 ° C. for 8 hours.

  By adding 5 parts by mass of the acrylic tackifying resin to 100 parts by mass of the solid content of the acrylic polymer (1) solution, and then adjusting with ethyl acetate so that the solid content becomes 30% by mass An acrylic adhesive was obtained. The acrylic pressure-sensitive adhesive a was obtained by mixing 0.3 parts by mass of the acrylic pressure-sensitive adhesive and the curing agent “E-2XM” (manufactured by Soken Chemical Co., Ltd., epoxy-based curing agent).

(Acrylic adhesive b)
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 75 parts by mass of methoxyethyl acrylate, 24 parts by mass of n-butyl acrylate, 1 part by mass of hydroxyethyl acrylate, 2 as a polymerization initiator , 2′-azobisisobutylnitrile dissolved in 100 parts by mass of ethyl acetate, purged with nitrogen, and polymerized at 80 ° C. for 8 hours to obtain an acrylic polymer (2) having a weight average molecular weight of 700,000. A solution was obtained.

  0.12 parts by mass of an isocyanate cross-linking agent (manufactured by Soken Chemical Co., Ltd., TD-75 solid content 75% by mass) is added to 100 parts by mass of the solid content of the acrylic copolymer (2) solution, and a stirrer is used. The mixture was stirred for 15 minutes to obtain an acrylic pressure-sensitive adhesive b.

(Acrylic adhesive c)
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 95.5 parts by mass of n-butyl acrylate, 0.5 parts by mass of 2-hydroxyethyl acrylate, 4.0 parts by mass of acrylic acid As a polymerization initiator, 0.2 parts by mass of 2,2′-azobisisobutylnitrile is dissolved in 100 parts by mass of ethyl acetate, and after substitution with nitrogen, polymerization is carried out at 80 ° C. for 8 hours to obtain an acrylic copolymer having a weight average molecular weight of 1,000,000. A solution of polymer (3) was obtained.

  10 parts by weight of “KE656” (Arakawa Chemical Industries, Ltd., disproportionated rosin ester) and “Pencel D135” (Arakawa Chemical Industries, Ltd.) with respect to 100 parts by mass of the solid content of the acrylic polymer (3) solution. , Polymerized rosin ester) 5 parts by mass and "FTR6100" (manufactured by Mitsui Chemicals, petroleum resin) 30 parts by mass are mixed and adjusted with toluene so that their solid content is 40% by mass. An agent was obtained. The acrylic pressure-sensitive adhesive is mixed with 1.3 parts by mass of “Coronate L-45” (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate-based cross-linking agent) and stirred for 15 minutes using a stirrer. c was obtained.

Example 1
To one side of a polyester film “A4300 # 38” (base material having a polyester-based easy-adhesion layer on both sides of the polyester film), which is a base material, using a lip coater, the silicone pressure-sensitive adhesive A is applied. The silicone pressure-sensitive adhesive layer (A) after drying was coated to a thickness of 30 μm and dried at 140 ° C. for 2 minutes to form the silicone pressure-sensitive adhesive layer (A).

  A single-sided pressure-sensitive adhesive tape was obtained by laminating a polyester film “E5000 # 50” manufactured by Toyobo Co., Ltd. as a release liner on the surface of the silicone pressure-sensitive adhesive layer (A).

  Next, a lip coater is placed on the release liner “PET38 × 1 A3” manufactured by Nipper Co., Ltd. so that the acrylic adhesive layer (B) after drying has a thickness of 20 μm. The acrylic pressure-sensitive adhesive layer (B) was formed by coating and drying at 100 ° C. for 2 minutes.

  Next, the acrylic pressure-sensitive adhesive layer (B) was applied to the other surface of the base material constituting the single-sided pressure-sensitive adhesive tape, and was cured at 40 ° C. for 48 hours to obtain a double-sided pressure-sensitive adhesive tape.

(Example 2)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive B was used in place of the silicone-based pressure-sensitive adhesive A.

(Example 3)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive B was used in place of the silicone-based pressure-sensitive adhesive A, and the thickness of the silicone-based pressure-sensitive adhesive layer (A) was changed from 30 μm to 50 μm. Obtained.

Example 4
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the silicone-based pressure-sensitive adhesive layer (A) was changed from 30 μm to 50 μm.

(Example 5)
A double-sided pressure-sensitive adhesive tape was used in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive B was used instead of the silicone-based pressure-sensitive adhesive A and the thickness of the acrylic pressure-sensitive adhesive layer (B) was changed from 20 μm to 50 μm. Obtained.

(Example 6)
A double-sided adhesive tape was prepared in the same manner as in Example 1 except that the silicone adhesive B was used in place of the silicone adhesive A and the thickness of the acrylic adhesive layer (B) was changed from 20 μm to 8 μm. Obtained.

(Example 7)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive B was used instead of the silicone-based pressure-sensitive adhesive A, and the acrylic pressure-sensitive adhesive b was used instead of the acrylic pressure-sensitive adhesive a. .

(Comparative Example 1)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive C was used in place of the silicone-based pressure-sensitive adhesive A.

(Comparative Example 2)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the silicone-based pressure-sensitive adhesive D was used instead of the silicone-based pressure-sensitive adhesive A, but the compatibility of the silicone-based pressure-sensitive adhesive D was poor and uniform. A coated surface could not be obtained and a double-sided adhesive tape could not be prepared.

(Comparative Example 3)
As a base material, instead of a polyester film “A4300 # 38” manufactured by Toyobo Co., Ltd. (a base material having a polyester-based easy adhesion layer on both sides of the polyester film), a polyester film “S10 # 38” manufactured by Toray Industries, Inc. (untreated) A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a polyester film and a substrate having no easy-adhesion layer were used.

(Measurement of tensile strength)
Under an environment of 23 ° C. and 50% RH, a 25 mm wide polyester film S-25 manufactured by Unitika Co., Ltd., 25 μm, was pressure-applied once with a 2.0 kg roller, and 1 at 23 ° C. and 50% RH. The test piece was left for a period of time. Using the tensile tester (Tensilon RTA-100, manufactured by A & D), the test piece was peeled off in the direction of 180 degrees at 23 ° C. and 50% RH at a tensile rate of 300 mm / min, and the adhesive strength was measured. did. The side opposite to the measurement surface was affixed and fixed to an aluminum plate with a DIC double-sided tape “# 8625UJ”.

  In an environment of 23 ° C. and 50% RH, the double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were cut into a size of 50 mm width and 100 mm length, and the surface made of the acrylic pressure-sensitive adhesive layer (B) and aluminum A test piece was prepared by bonding the acrylic adhesive layer (B) to the plate using a double-sided adhesive tape “# 8625UJ” manufactured by DIC Corporation.

  The test piece was placed so that the silicone-based pressure-sensitive adhesive layer (A) was on the upper surface, and “S-25” (manufactured by Unitika Ltd.) cut into a width of 25 mm on the silicone-based pressure-sensitive adhesive layer (A). A polyester film having a thickness of 25 μm) was placed, and the upper surface thereof was pressure-applied by reciprocating a 2 kg roller once, and then left at 23 ° C. and 50% RH for 1 hour.

  Thereafter, using a tensile tester (Tensilon RTA-100, manufactured by A & D Co., Ltd.) in a 23 ° C. and 50% RH environment, the “S-25” was changed to the silicone-based pressure-sensitive adhesive under the conditions of a tensile speed of 300 mm / min. The adhesive strength was measured when the layer (A) was pulled in the direction of 180 ° with respect to the surface and peeled off.

  Moreover, the surface which consists of the silicone adhesive layer (A) which cut | judged the double-sided adhesive tape obtained by the Example and the comparative example in the environment of 23 degreeC and 50% RH to the magnitude | size of 50 mm width and 100 mm length. And the aluminum plate were bonded together using a double-sided pressure-sensitive adhesive tape “# 8625HPW” manufactured by DIC Corporation, and the silicone-based pressure-sensitive adhesive layer (A) was lined as a test piece.

  The test piece was placed so that the acrylic pressure-sensitive adhesive layer (B) was on the upper surface, and cut into a width of 25 mm on the acrylic pressure-sensitive adhesive layer (B) (“S-25” manufactured by Unitika Ltd., Polyester film (thickness 25 μm) was placed, and the upper surface thereof was pressure-applied by reciprocating a 2 kg roller once, and then left at 23 ° C. and 50% RH for 1 hour.

  Thereafter, using a tensile tester (Tensilon RTA-100, manufactured by A & D) at 23 ° C. and 50% RH, the “S-25” was converted to the acrylic pressure-sensitive adhesive under the conditions of a tensile speed of 300 mm / min. The adhesive strength was measured when the layer (B) was pulled in the 180 ° direction with respect to the surface and peeled off.

(Transmittance)
The total light transmittance of the double-sided pressure-sensitive adhesive tape was measured according to JIS K7361-1: 2000.

(Haze)
The haze of a test piece obtained by attaching two transparent glass plates using the double-sided pressure-sensitive adhesive tape was measured according to JIS K7136: 2000.

(Air release)
The acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and a tempered glass having a thickness of 0.4 mm are laminated, and the upper surface thereof is moved back and forth once by a 2 kg roller. The protective member (FIG. 1) was obtained by pasting and autoclaving (standing at 60 ° C. and 0.5 MPa for 30 minutes).

  Next, a test piece obtained by manually attaching the silicone-based pressure-sensitive adhesive layer (A) of the protective member and a plate glass having a thickness of 1 mm was placed on black polyethylene terephthalate.

Starting from the time when the protective member and the plate glass are pasted, when it can be visually confirmed that all the air bubbles (air) entrapped at the interface between the silicone pressure-sensitive adhesive layer (A) and the plate glass have been removed. The time until was measured.
A: All bubbles (air) were released within 3 hours.
○: Over 3 hours and all bubbles (air) were released within 24 hours.
X: Some bubbles (air) remained even after 24 hours.

(Reworkability: Silicone adhesive layer (A))
The test piece after the evaluation of the “air release property” was left in an environment of 23 ° C. and 50% RH for 7 days, and then the plate glass and the protective member constituting the test piece were disassembled by hand. The adhesive residue at that time and the crack of the tempered glass were evaluated.

  Moreover, after leaving the test piece after evaluating the “air release property” in an environment of 60 ° C. and 90% RH for 7 days, the plate glass and the protective member constituting the test piece are dismantled by hand. did. The adhesive residue at that time and the crack of the tempered glass were evaluated.

  A: In any of the above tests, there was no adhesive residue at a level that could be visually confirmed, and no breakage of the tempered glass occurred.

  ○: In the test of disassembling the test piece after being left for 7 days in an environment of 23 ° C. and 50% RH, there was no adhesive residue at a level that could be visually confirmed, and cracking of the tempered glass did not occur, but 60 ° C. In the test for disassembling the test piece after being left in an environment of 90% RH for 7 days, some glue residue or tempered glass cracking was observed.

  X: In the test of disassembling the test piece after being left for 7 days in an environment of 23 ° C. and 50% RH, clear adhesive residue or tempered glass cracking was observed.

(Reworkability: Acrylic adhesive layer (B))
By laminating the surface of the acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and tempered glass having a thickness of 0.4 mm, and reciprocating the upper surface of the 2 kg roller once. A test piece was prepared by bonding them together.

  The test piece was left in an environment of 23 ° C. and 50% RH for 7 days, and then the tempered glass and the double-sided adhesive tape constituting the test piece were disassembled by hand. The adhesive residue at that time and the crack of the tempered glass were evaluated.

  Further, after the test piece prepared by the above method is autoclaved (left in an environment of 60 ° C. and 0.5 MPa for 30 minutes), the tempered glass and the double-sided adhesive tape constituting the test piece are dismantled by hand. did. The adhesive residue at that time and the crack of the tempered glass were evaluated.

  A: In any of the above tests, there was no adhesive residue at a level that could be visually confirmed, and no breakage of the tempered glass occurred.

  ○: In the test of disassembling the test piece after being left for 7 days in an environment of 23 ° C. and 50% RH, there was no adhesive residue at a level that could be visually confirmed, and cracking of the tempered glass did not occur, but autoclave treatment In the test of disassembling the later test piece, some adhesive residue or tempered glass cracking was observed.

  X: In the test of disassembling the test piece after being left for 7 days in an environment of 23 ° C. and 50% RH, clear adhesive residue or tempered glass cracking was observed.

(Impact resistance)
The acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and a tempered glass having a thickness of 0.4 mm are laminated, and the upper surface thereof is moved back and forth once by a 2 kg roller. The protective member was obtained by pasting and autoclaving (standing at 60 ° C. and 0.5 MPa for 30 minutes).

  A test piece was prepared by pasting the silicone-based pressure-sensitive adhesive layer (A) constituting the protective member on an information display part (glass) of a display of iPhone 5S (registered trademark) manufactured by Apple (Apple).

After dropping the test piece from the position of 1 m height onto the concrete surface, it was evaluated whether or not the protective member was peeled off from the information display surface of the display.
A: No peeling at all.
○: The edge of the protective member peeled off from the information display surface very slightly.
X: The range of 5% or more of the sticking area of the protective member was peeled off from the information display surface.

(Spattering prevention)
The acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and a tempered glass having a thickness of 0.4 mm are laminated, and the upper surface thereof is moved back and forth once by a 2 kg roller. The protective member was obtained by pasting and autoclaving (standing at 60 ° C. and 0.5 MPa for 30 minutes). A test piece was prepared by manually attaching the protective member to the surface of a plate glass having a thickness of 1 mm.

  When the test piece was placed so that the surface made of the protective member faced up and a 40 g stainless ball was dropped from a height of 1.5 m onto the surface made of the protective member, the tempered glass was We evaluated whether or not it would scatter.

  ○: The tempered glass was broken, but the fragments were not scattered around.

  X: The tempered glass was broken, and the fragments were scattered around.

(appearance)
The acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and a tempered glass having a thickness of 0.4 mm are laminated, and the upper surface thereof is moved back and forth once by a 2 kg roller. The protective member was obtained by pasting and autoclaving (standing at 60 ° C. and 0.5 MPa for 30 minutes).

  A silicone adhesive layer (A) constituting the protective member is attached to an information display part (glass) of a display of iPhone5S (registered trademark) manufactured by Apple (Apple) under an environment of 23 ° C. The test piece was left for 24 hours.

  The test piece was visually observed to evaluate the presence or absence of fogging.

  A: The protective member was not fogged at all, and the image displayed on the information display unit could be clearly seen.

◯: Some fogging was observed in a small part of the protective member, but the image displayed on the information display unit was practically sufficiently visible.
X: Since part of the protective member was cloudy, the image displayed on the information display unit could not be sufficiently visually confirmed.

(Adhesion between substrate and silicone adhesive layer)
The acrylic pressure-sensitive adhesive layer (B) of the double-sided pressure-sensitive adhesive tape obtained in Examples and Comparative Examples and a tempered glass having a thickness of 0.4 mm are laminated, and the upper surface thereof is moved back and forth once by a 2 kg roller. The protective member was obtained by pasting and autoclaving (standing at 60 ° C. and 0.5 MPa for 30 minutes).

  A test piece was prepared by pasting the silicone-based pressure-sensitive adhesive layer (A) constituting the protective member on an information display part (glass) of a display of iPhone 5S (registered trademark) manufactured by Apple (Apple).

  The test piece was left in an environmental tester at 60 ° C. and 90% RH for 200 hours, and it was evaluated whether or not the silicone adhesive dropped from the base material when the protective member was peeled off from iPhone 5S.

  ○: No adhesive residue.

  X: There is adhesive residue.

1 Tempered glass 2 Acrylic adhesive layer (B)
3 Substrate 4 Silicone adhesive layer (A)

Claims (9)

A pressure-sensitive adhesive tape having a structure in which a silicone-based pressure-sensitive adhesive layer (A) is laminated on at least one surface side of a substrate via an easy-adhesion layer, wherein the silicone-based pressure-sensitive adhesive layer (A) is silicone A pressure-sensitive adhesive tape characterized by being a layer formed using a silicone-based pressure-sensitive adhesive containing a compound (a1), an aromatic hydrocarbon solvent (a2), and a ketone solvent (a3). The pressure-sensitive adhesive tape according to claim 1, wherein the easy-adhesion layer is a layer containing polyester. The mass ratio of the aromatic hydrocarbon solvent (a2) and the ketone solvent (a3) [the aromatic hydrocarbon solvent (a2) / the ketone solvent (a3)] is 50/50 to 90/10. The pressure-sensitive adhesive tape according to claim 1 or 2, which is in a range of One side of the substrate has the silicone pressure-sensitive adhesive layer (A) via an easy-adhesion layer, and the other side of the substrate directly or via an easy-adhesion layer is acrylic. The pressure-sensitive adhesive tape according to claim 1, which has a pressure-sensitive adhesive layer (B). Measured by attaching a polyethylene terephthalate film having a thickness of 25 μm to the silicone-based pressure-sensitive adhesive layer (A) and pulling the polyethylene terephthalate film in a 180 ° direction with respect to the surface of the silicone-based pressure-sensitive adhesive layer (A). A polyethylene terephthalate film having a tensile strength in the range of 0.01 N / 25 mm to 0.1 N / 25 mm and having a thickness of 25 μm is pasted on the acrylic pressure-sensitive adhesive layer (B). The pressure-sensitive adhesive tape according to claim 4, wherein the tensile strength measured by pulling in a 180 ° direction with respect to the surface of the system pressure-sensitive adhesive layer (B) is in the range of 5 N / 25 mm to 28 N / 25 mm. A pressure-sensitive adhesive tape used for bonding between an information display portion of a display and a member made of glass or resin, wherein the silicone-based pressure-sensitive adhesive layer (A) constituting the pressure-sensitive adhesive tape is attached to the surface of the information display portion The pressure-sensitive adhesive tape according to claim 4 or 5, wherein the acrylic pressure-sensitive adhesive layer (B) is affixed to a surface of a member made of glass or resin. By applying and drying a silicone pressure-sensitive adhesive containing a silicone compound (a1), an aromatic hydrocarbon solvent (a2) and a ketone solvent (a3) on the surface of the easy-adhesion layer of the substrate. A method for producing a pressure-sensitive adhesive tape comprising forming a silicone-based pressure-sensitive adhesive layer (A). The protective member which has the structure by which the member which consists of glass or resin was previously affixed on the surface of the said acrylic adhesive layer (B) which the adhesive tape of any one of Claims 4-6 has. The electronic device which has the structure by which the protection member of Claim 8 was affixed on the surface of the information display part of the said display.

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