JP2017014332A - Adhesive tape and manufacturing method therefor, article and portable electronic terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape easy to be processed to any fine width shape even with thin and having excellent followability to an adherend even with thin or fine width.SOLUTION: The invention relates to an adhesive tape having an adhesive layer (B) on at least one surface side of a film substrate (A) having tensile breaking elongation measured by being pulled at tensile rate of 300 mm/min. of 900% or more and tensile breaking strength of 2000 N/cm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure-sensitive adhesive tape that can be used for bonding various adherends.

  Adhesive tapes are widely used, for example, in scenes such as fixing parts constituting electronic equipment. Specifically, the adhesive tape is fixed to a protective panel and a casing of an image display unit constituting a small electronic device such as a portable electronic terminal, a camera, a personal computer, an exterior component or a battery to the small electronic device. Used for fixing rigid parts.

  As the pressure-sensitive adhesive tape, a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on both sides of a flexible foam base material is known as a thin, excellent followable to an adherend and excellent in water resistance. (For example, refer to Patent Document 1).

  However, the adhesive tape using the conventional foam base material is inevitably caused by the thickness of the foam base material, while further thinning of the adhesive tape is required with the thinning of portable electronic terminals and the like. Since the film tends to be thick, it may not be able to sufficiently meet the market demand for thinning.

  On the other hand, the pressure-sensitive adhesive tape is also required to have a narrow width, which is not limited to the above-mentioned thinning, and even a pressure-sensitive adhesive tape having a width of less than 1 mm is required to have an excellent adhesive force.

  However, in the case of conventional adhesive tape, when it is attempted to punch into a frame shape having a width of less than 1 mm, for example, it cannot be punched into a predetermined shape, or wrinkles occur, resulting in excellent adhesive strength. May not be expressed.

JP 2013-53177 A

  The problem to be solved by the present invention is that the pressure-sensitive adhesive tape can be easily processed into an arbitrary narrow shape even if it is thin, and has excellent followability to the adherend even if it is thin or narrow. Is to provide.

The inventors have at least a film substrate (A) having a tensile breaking elongation measured by pulling at a tensile speed of 300 mm / min of 450% or more and a tensile breaking strength of 2000 N / cm ² or more. The said subject was solved by the adhesive tape characterized by having an adhesive layer (B) in one surface side.

  Even if the pressure-sensitive adhesive tape of the present invention is thin or narrow, it has excellent followability to the adherend and waterproof property, and excellent antistatic properties.

It is the conceptual diagram which looked at the evaluation method of the insulation test from the cross-sectional direction.

The pressure-sensitive adhesive tape of the present invention has a tensile strength at break of 900% or more measured by pulling at a pulling speed of 300 mm / min, and a film substrate (A) having a tensile strength at break of 2000 N / cm ² or more. It has an adhesive layer (B) on at least one surface side.

  As 1st embodiment of the adhesive tape of this invention, the single-sided adhesive tape by which the adhesive layer (B) was laminated | stacked on the one surface side of the said film base material (A), for example, or the said film base material (A ), And a double-sided pressure-sensitive adhesive tape in which the pressure-sensitive adhesive layer (B) is laminated. The pressure-sensitive adhesive layer (B) may be directly laminated on the surface of the film substrate (A), or may be laminated via another layer such as a foam substrate layer. The double-sided pressure-sensitive adhesive tape may have a pressure-sensitive adhesive layer having the same pressure-sensitive adhesive force on each surface of the film base material (A), or may have pressure-sensitive adhesive layers having different pressure-sensitive adhesive forces. May be.

[Film substrate (A)]
The pressure-sensitive adhesive tape of the present invention has a film base having a tensile breaking elongation of 450% or more and a tensile breaking strength of 2000 N / cm ² or more as a so-called core as measured by pulling at a tensile speed of 300 mm / min. The material (A) is used. By using the specific film substrate (A), an adhesive tape that can be easily processed into an arbitrary narrow shape even if it is thin, has excellent followability to an adherend, and has excellent anti-static properties. Can be obtained.

  The tensile elongation at break is preferably 450% or more, and preferably 600% or more, even if it is thin, it can be easily processed into an arbitrary narrow shape, has excellent followability to the adherend, and It is more preferable for obtaining a pressure-sensitive adhesive tape having excellent antistatic properties. The upper limit of the tensile elongation at break is preferably 1000%.

Further, the tensile strength is preferably at 2000N / cm ² or more, it is 2500N / cm ² or more, easily processed into any narrow shape even thin, followability to adherends It is more preferable for obtaining a pressure-sensitive adhesive tape excellent in antistatic properties.

  The film substrate (A) preferably has a thickness of 200 μm or less, more preferably has a thickness of 10 μm to 200 μm, and still more preferably has a thickness of 10 μm to 150 μm. It is particularly preferable to use one having a thickness of 40 μm to 130 μm. In addition, the thickness of the said film base material (A) is an average value of the value obtained by measuring the thickness of five places selected at random among the said film base materials (A). By using the film base material (A) having a thickness within the above range, the film base material (A) can be easily formed, and even if it is thin, it can be easily processed into an arbitrary narrow shape, and follows the adherend. It is possible to obtain a pressure-sensitive adhesive tape having excellent properties and electrostatic resistance.

  Moreover, as said film base material (A), in order to obtain the adhesive tape provided with the further outstanding followable | trackability and impact resistance, what was foamed may be sufficient, but the thinning of the adhesive tape and the excellent Non-foaming is preferable for achieving both conformability, waterproofness, antistatic properties, and the like.

  As the film substrate (A), any layer having the specific tensile elongation at break and tensile break strength can be used. Is more preferable for obtaining a pressure-sensitive adhesive tape that can be easily processed into an arbitrary narrow shape, has excellent followability to an adherend, and has excellent anti-static properties.

  As the polyurethane-based substrate, for example, a film substrate formed using a so-called two-component curable composition containing a hydroxyl group-containing polyurethane, polyisocyanate, and, if necessary, a solvent may be used. Even if it is thin, it is easy to process into an arbitrary narrow shape, and is more preferable for obtaining a pressure-sensitive adhesive tape excellent in followability to an adherend and excellent in anti-static properties.

  As the polyurethane having a hydroxyl group that can be used in the two-component curable composition, for example, those obtained by reacting polyisocyanate and polyol can be used.

  Examples of the polyisocyanate that can be used for producing the polyurethane having a hydroxyl group include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, triphenylmethane triisocyanate, and polyphenyl polymethylene polyisocyanate. Aromatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate and the like, polyisocyanates having carbodiimide groups A polyisocyanate having an allophanate group , It can be used polyisocyanates containing isocyanurate groups.

  Among them, it is preferable to use aromatic polyisocyanate as the polyisocyanate, and use of 4,4′-diphenylmethane diisocyanate has the predetermined tensile breaking elongation and tensile breaking strength and is thin. However, it is more preferable to obtain a pressure-sensitive adhesive tape that can be easily processed into an arbitrary narrow shape, has excellent followability to an adherend, and has excellent anti-static properties.

  Examples of polyols that can be used in the production of the polyurethane having a hydroxyl group include polyether polyols, polyester polyols, and polyether ester polyols, which can be used alone or in combination of two or more, and polyester polyols are preferably used. .

  Moreover, as said polyester polyol, what is obtained by making polycarboxylic acid and a polyol react can be used.

  Examples of the polycarboxylic acid include aliphatic polycarboxylic acids such as succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid, and aromatics such as o-phthalic acid. A group polycarboxylic acid or the like can be used.

  Examples of polyols that can be used in the production of the polyester polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2 -Dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexane-1,4 -Diol, cyclohexane-1,4-dimethanol and the like can be used.

  Moreover, as said polyester polyol, ring-opening polymerization products, such as (gamma) -butyrolactone and (epsilon) -caprolactone, poly (hexamethylene carbonate) diol, etc. can also be used.

  As the polyester polyol, an aliphatic polyester polyol is preferably used.

  As the polyether polyol, for example, those obtained by ring-opening polymerization of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran and the like using the polyol or polyamine as an initiator can be used.

  As the polyester ether polyol, for example, a copolymer of the above-described polyester polyol and polyether polyol can be used.

  Moreover, as said polyol, the low molecular weight polyol whose molecular weight is 60-140 can also be used. Examples of the low molecular weight polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3- Propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, Cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, sorbitol, methylglycoside, etc. can be used, and 1,4-butanediol can be used before To obtain a pressure-sensitive adhesive tape that has a predetermined tensile breaking elongation and tensile breaking strength, can be easily processed into an arbitrary narrow shape even if it is thin, has excellent followability to an adherend, and has excellent anti-static properties. And more preferable.

  Examples of polyisocyanates that can be used in combination with the polyurethane having a hydroxyl group in the two-component curable composition include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, triphenylmethane triisocyanate, and polyphenyl. Aromatic or alicyclic polyisocyanates such as aromatic polyisocyanates such as polymethylene polyisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, Polyisocyanate having carbodiimide group, allophane Polyisocyanates having bets group, polyisocyanates containing isocyanurate groups, and can use them adducts and the like.

Among these, as the polyisocyanate, it is preferable to use an aromatic polyisocyanate, and using tolylene diisocyanate or its trimethylolpropane adduct has the predetermined tensile breaking elongation and tensile breaking strength, Even if it is thin, it is easy to process into an arbitrary narrow shape, which is more preferable for obtaining a pressure-sensitive adhesive tape excellent in followability to an adherend and excellent in anti-static properties.

  As said film base material (A), the two-component curable composition containing an additive and a solvent can be used as needed.

  Examples of the solvent include esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; ethers such as methyl cellosolve acetate and butyl cellosolve acetate; toluene, xylene Aromatic hydrocarbon solvents such as amides such as dimethylformamide and dimethylacetamide can be used.

  The film base (A) can be produced, for example, by coating the surface of the release sheet with a two-component curable composition containing the above additives, a solvent, and the like, if necessary, and drying. it can.

  Examples of the two-component curable composition include a composition containing the resin or the like and an organic solvent, a composition containing the resin or the like and an aqueous medium, and a solventless composition that substantially does not contain the solvent. Etc. can be used. Among them, the two-component curable composition has the predetermined tensile breaking elongation and tensile breaking strength, and can be easily processed into an arbitrary narrow shape even if it is thin, and has excellent followability to an adherend. And it is more preferable to use what contains the said polyisocyanate, a polyol, and a solvent, when obtaining the adhesive tape excellent in the antistatic property.

  As a method of forming the film substrate (A) using the two-component curable composition, for example, a composition containing a polyurethane having a hydroxyl group and a solvent, and the polyisocyanate were mixed. A step of coating the two-component curable composition on the surface of the release film by a comma coater method, and drying the coated product in an environment at a temperature of 140 ° C., thereby providing a solvent contained in the two-component curable composition And a step of curing and reacting the coated material for 72 hours in an environment of a temperature of 40 ° C. and a relative humidity of 50%.

[Adhesive layer (B)]
Next, the adhesive layer (B) which comprises the adhesive tape of this invention is demonstrated.

  The pressure-sensitive adhesive layer (B) is a layer that adheres to the adherend. In the double-sided pressure-sensitive adhesive tape which is one embodiment of the present invention, the pressure-sensitive adhesive layers (B) provided on both surfaces of the film base (A) respectively have pressure-sensitive adhesive layers having the same adhesive force. It may have a pressure-sensitive adhesive layer having different adhesive strength.

  The pressure-sensitive adhesive layer (B) can be formed using various pressure-sensitive adhesives.

  Examples of the pressure-sensitive adhesive include natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and vinyl ether-based pressure-sensitive adhesives. As the form of the pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a water-based pressure-sensitive adhesive such as a water-soluble pressure-sensitive adhesive, a hot-melt pressure-sensitive adhesive, a UV curable pressure-sensitive adhesive, and an EB-curable pressure-sensitive adhesive. An adhesive etc. are mentioned.

  Especially, as said adhesive, it is preferable to use the acrylic adhesive which contains an acrylic polymer and contains tackifying resin, a crosslinking agent, etc. as needed.

  As the acrylic polymer, it is preferable to use a polymer obtained by polymerizing a vinyl monomer component containing a vinyl monomer.

  Examples of the (meth) acrylic monomer that can be used for the production of the acrylic polymer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t- Carbon such as butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate A (meth) acrylate having an alkyl group having 1 to 12 atoms can be used.

  Among these, as the (meth) acrylic monomer, it is preferable to use a (meth) acrylate having an alkyl group having 4 to 12 carbon atoms, and having an alkyl group having 4 to 8 carbon atoms. It is more preferable to use (meth) acrylate, and the use of any one of n-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate or a combination thereof further improves impact resistance and peel adhesion. It is preferable for obtaining a pressure-sensitive adhesive sheet that satisfies both of the above.

  The (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used in an amount of 60% by mass or more, based on the total amount of monomers used for the production of the acrylic polymer. It is more preferable to use in the range of 98.5% by mass, and use in the range of 90% by mass to 98.5% by mass has superior adhesive strength such as push strength and static load holding force. It is preferable when obtaining an adhesive tape.

  Moreover, when manufacturing the said acrylic polymer, a highly polar vinyl monomer can be used as a monomer. As the highly polar vinyl monomer, a vinyl monomer having a hydroxyl group, a vinyl monomer having a carboxyl group, a vinyl monomer having an amide group, or the like can be used alone or in combination.

  Examples of the monomer having a hydroxyl group include a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. (Meth) acrylates can be used.

  As the vinyl monomer having a carboxyl group, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth) acrylic acid dimer, crotonic acid, ethylene oxide-modified oxalic acid acrylate, etc. can be used. Of these, acrylic acid is preferably used.

  As the monomer having an amide group, for example, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N, N-dimethylacrylamide and the like can be used.

  As the high-polarity vinyl monomer, vinyl acetate, ethylene oxide-modified succinic acid acrylate, 2-acrylamido-2-methylpropane sulfonic acid and the like can be used in addition to those described above.

  The high-polarity vinyl monomer is preferably used in a range of 1.5% by mass to 20% 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 to 10% by mass, and it is more preferable to use in the range of 2 to 8% by mass in order to achieve both excellent adhesive force and excellent followability.

  When using the thing containing the crosslinking agent mentioned later as the said adhesive, it is preferable to use the acrylic polymer which has a functional group which reacts with the functional group which the said crosslinking agent has as said acrylic polymer. Examples of the functional group that the acrylic polymer may have include a hydroxyl group.

  The hydroxyl group can be introduced into the acrylic polymer, for example, by using a vinyl monomer having a hydroxyl group as the monomer.

  The vinyl monomer having a hydroxyl group is preferably used in the range of 0.01% by mass to 1.0% 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 mass% to 0.3 mass%.

  The acrylic polymer can be produced by polymerizing the monomer by a method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, etc., and adopting a solution polymerization method Is preferable for improving the production efficiency of the acrylic polymer.

  Examples of the solution polymerization method include a method of radical polymerization by mixing and stirring the monomer, a polymerization initiator, and an organic solvent, preferably at a temperature of 40 ° C. to 90 ° C.

  Examples of the polymerization initiator include peroxides such as benzoyl peroxide and lauryl peroxide, azo thermal polymerization initiators such as azobisisobutylnitrile, acetophenone photopolymerization initiators, benzoin ether photopolymerization initiators, benzyl A ketal photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator, a benzoin photopolymerization initiator, a benzophenone photopolymerization initiator, or the like can be used.

  The acrylic polymer obtained by the above method may be in a state of being dissolved or dispersed in an organic solvent as long as it is produced by a solution polymerization method, for example.

  As said acrylic polymer, it is preferable to use what has a weight average molecular weight of 400,000-3 million, and it is more preferable to use what has a weight average molecular weight of 700,000-2,500,000.

  The weight average molecular weight is a value measured by gel permeation chromatography (GPC method) and calculated in terms of standard polystyrene. Specifically, the weight average molecular weight can be measured under the following conditions using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation.

Sample concentration: 0.5% by mass (tetrahydrofuran solution)
Sample injection volume: 100 μl
Eluent: Tetrahydrofuran Flow rate: 1.0 ml / min Measuring temperature: 40 ° C
This column: TSKgel GMHHR-H (20) 2 Guard column: TSKgel HXL-H
Detector: Differential refractometer Weight average molecular weight of standard polystyrene: 10,000 to 20 million (manufactured by Tosoh Corporation)

  As a pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer (B), it is preferable to use a pressure-sensitive adhesive containing a tackifying resin in order to obtain a pressure-sensitive adhesive tape having excellent adhesive strength such as push strength and static load holding force. preferable.

  Examples of the tackifying resin include a rosin tackifying resin, a polymerized rosin tackifying resin, a polymerized rosin ester tackifying resin, a rosin phenol tackifying resin, a stabilized rosin ester tackifying resin, and a disproportionated rosin ester. -Based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene-based tackifier resins, terpene phenol-based tackifier resins, petroleum resin-based tackifier resins, (meth) acrylate resin-based tackifier resins, and the like. . When using an emulsion-type pressure-sensitive adhesive as the pressure-sensitive adhesive, it is preferable to use an emulsion-type tackifying resin as the tackifying resin.

  Examples of the tackifying resin include disproportionated rosin ester tackifying resin, polymerized rosin ester tackifying resin, rosin phenol tackifying resin, hydrogenated rosin ester tackifying resin, (meth) acrylate, among others. It is preferable to use one or a combination of two or more of resins, terpene phenol resins, and petroleum resins.

  As the tackifier resin, those having a softening point in the range of 30 ° C. to 180 ° C. are preferable, and those in the range of 70 ° C. to 140 ° C. are excellent in push strength and static resistance on the adherend. It is more preferable to achieve both adhesive force such as load holding force and excellent followability. When the (meth) acrylate tackifying resin is used, it is preferable to use a (meth) acrylate tackifying resin having a glass transition temperature of 30 ° C. to 200 ° C., and a resin having a temperature of 50 ° C. to 160 ° C. It is more preferable.

  The tackifying resin is preferably used in a range of 5 to 65 parts by mass, and in a range of 8 to 55 parts by mass, with respect to 100 parts by mass of the acrylic polymer. And more preferable for obtaining a pressure-sensitive adhesive tape having excellent adhesive strength such as static load retention.

  As the pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer (B), it is preferable to use a cross-linking agent in order to obtain a pressure-sensitive adhesive tape having excellent adhesive strength such as push strength and static load holding force.

  As said crosslinking agent, an isocyanate type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent, an aziridine type crosslinking agent etc. can be used, for example. Especially, as said crosslinking agent, it is preferable to use any one or both of the isocyanate type crosslinking agent and epoxy-type crosslinking agent which are rich in the reactivity with an acrylic polymer, and using an isocyanate type crosslinking agent is preferable. More preferred.

  Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, and the like. It is preferable to use trimethylolpropane-modified tolylene diisocyanate.

  The crosslinking agent is preferably selected and used in such an amount that the gel fraction with respect to toluene in the pressure-sensitive adhesive layer (B) is 70% by mass or less, and the amount in which the gel fraction is 20% by mass to 60% by mass is selected. It is more preferable to use it, and it is possible to obtain a pressure-sensitive adhesive tape that is more excellent in adhesive strength such as push strength and static load holding force by selecting and using an amount with a gel fraction of 25 mass% to 55 mass%. Furthermore, it is more preferable.

  In addition, the said gel fraction points out the value measured by the method shown below.

  The pressure-sensitive adhesive coated on the release treatment surface of the release liner so that the thickness after drying is 50 μm is dried for 3 minutes in an environment of 100 ° C., and then 2 in an environment of 40 ° C. The pressure-sensitive adhesive layer was formed by aging for a day.

  A test piece was prepared by cutting the pressure-sensitive adhesive layer into a square of 50 mm length and 50 mm width.

  After measuring the mass (G1) of the test piece, the test piece was immersed in toluene for 24 hours in an environment of 23 ° C.

  After the immersion, the mixture of the test piece and toluene was filtered using a 300 mesh wire net to extract insoluble components in toluene. The mass (G2) of the insoluble component dried at 110 ° C. for 1 hour was measured.

  The gel fraction was calculated based on the mass (G1), the mass (G2), and the following formula.

    Gel fraction (mass%) = (G2 / G1) × 100

  Examples of the pressure-sensitive adhesive include plasticizers, softeners, antioxidants, flame retardants, glass and plastic fibers and balloons, beads, metals, metal oxides, metal nitride fillers, pigments, dyes, and the like. What contains additives, such as a coloring agent, a leveling agent, a thickener, a water repellent, an antifoamer, can be used.

  As the pressure-sensitive adhesive, it is preferable to use a pressure-sensitive adhesive containing a solvent for maintaining good coating workability. Examples of the solvent include toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane, and the like. Moreover, when setting it as an aqueous adhesive composition, water or the aqueous solvent which has water as a main can be used.

  If the pressure-sensitive adhesive tape of the present invention is, for example, the pressure-sensitive adhesive tape of the first embodiment, the step of forming the pressure-sensitive adhesive layer (B) by coating the pressure-sensitive adhesive on the surface of the release sheet and drying, It can manufacture by passing the process of transferring the said adhesive layer (B) to the one or both surfaces of the film base material (A) previously manufactured by the said method. Moreover, the said adhesive tape can also be manufactured by forming an adhesive layer (B) by coating and drying the said adhesive directly on the single side | surface or both surfaces of the said film base material (A) manufactured previously. it can.

  When using an adhesive containing an acrylic polymer and a crosslinking agent as an adhesive forming the adhesive layer (B), the adhesive was applied to the surface of the film substrate (A) and dried. The film base (A) and the pressure-sensitive adhesive layer (B) are preferably aged for about 2 to 7 days in an environment of 20 ° C. to 50 ° C., more preferably 23 ° C. to 45 ° C. It is preferable for obtaining a pressure-sensitive adhesive tape that is firmly bonded.

  The thickness of the pressure-sensitive adhesive layer (B) formed by the above method is 5 μm to 5 μm in order to achieve both excellent adhesive strength such as push strength and static load holding force on the adherend and excellent followability. The thickness is preferably 100 μm, more preferably 10 μm to 80 μm, and particularly preferably 15 μm to 80 μm.

  As the pressure-sensitive adhesive tape of the present invention obtained by the above method or the like, it is preferable to use a tape having a thickness of 300 μm or less because it easily contributes to thinning of a small electronic device, and a tape having a thickness of 10 μm to 280 μm is used. It is more preferable. Further, in the small electronic device, when it is particularly required to reduce the thickness, it is preferable that the thickness is 200 μm or less, more preferably 50 μm to 180 μm.

  Moreover, as an adhesive tape of this invention, what has another layer other than the said film base material (A) and an adhesive layer (B) as needed can be used.

  Examples of the other layers include a laminated layer such as a polyester film, a light-shielding layer, a light reflection layer, a metal layer, and other heat conductive layers, for example, for imparting dimensional stability and good tensile strength and reworkability of the pressure-sensitive adhesive sheet. Is mentioned.

  As an adhesive tape of this invention, the peeling sheet may be laminated | stacked on the surface of the adhesive layer (B).

  As the release sheet, for example, a film obtained by using a synthetic resin such as polyethylene, polypropylene, polyester, paper, non-woven fabric, cloth, foamed sheet, metal substrate, and at least one side of a laminate thereof is treated with silicone. In addition, those subjected to a peeling treatment such as a long-chain alkyl treatment or a fluorine treatment can be used.

  The pressure-sensitive adhesive tape of the present invention can be used, for example, for fixing a member whose width of the narrowest portion of the pressure-sensitive adhesive tape is limited to 5 mm or less due to restrictions such as an application site and a shape. In that case, as the adhesive tape, it is preferable to use a tape cut to a width of 5 mm or less, more preferably a tape cut to a width of 0.1 mm to 3 mm, and a cut to 0.1 mm to 1 mm. It is more preferable to use what was cut, and it is especially preferable to use what was cut | judged by the width | variety of 0.1 mm-0.8 mm.

  The narrow member is often used as a member in industrial applications such as electronic terminals such as mobile phones, automobiles, building materials, OA, and home appliance industries.

  Specific examples of the member include two or more casings and lens members that constitute an electronic terminal.

  As the pressure-sensitive adhesive tape, it is preferable to use one cut into a frame shape or the like, for example, when fixing two or more casings constituting the information display device such as a display, and the casing and the lens member. can do.

  An article such as an electronic terminal to which two or more cases and lens members are fixed using the pressure-sensitive adhesive sheet of the present invention is not easily disassembled by an impact such as dropping, and has an excellent waterproof property.

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

[Production Example 1]
65.1 parts by mass of polybutylene adipate polyol having a number average molecular weight of 600 obtained by reacting 1,4-butanediol and adipic acid was mixed with a mixed solvent of dimethylformamide and methyl ethyl ketone (dimethylformamide / methyl ethyl ketone = 30/70 mass). The ratio was diluted 1.7 times.

  Next, 2.3 parts by mass of 1,4-butanediol and 32.6 parts by mass of 4,4′-diphenylmethane diisocyanate are mixed with the dilution and reacted at 80 ° C. for 3 hours, whereby a polyurethane having a hydroxyl group is obtained. A solution (non-volatile content 50 mass%, viscosity 4200 mPa · s at 25 ° C.) was obtained.

  Next, the polyurethane solution having the hydroxyl group and Vernock NC-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7 mass%, nonvolatile content 40 mass%) 7.0 mass The two-part curable composition obtained by mixing the part is applied to the release-treated surface of the release sheet so that the thickness after curing is 100 μm, and the temperature is 120 ° C. for 10 minutes. The film base material layer (A-1) was produced by making it dry.

[Production Example 2]
Obtained by reacting 1,2-hexanediol and neopentyl glycol with 42.0 parts by mass of a polyester polyol having a number average molecular weight of 1,500 obtained by reacting with adipic acid, and 1,4-butanediol with adipic acid. 18.0 parts by mass of polybutylene adipate polyol having a number average molecular weight of 600 and 0.5 parts by mass of trimethylolpropane were diluted 1.7 times with ethyl acetate.

  Next, 10.0 parts by mass of tolylene diisocyanate is mixed with the diluted product and reacted at 80 ° C. for 3 hours to obtain a polyurethane solution having a hydroxyl group (nonvolatile content: 70% by mass, viscosity of 50000 mPa · s at 25 ° C.). Obtained.

  The polyurethane solution having a hydroxyl group and 9.8 parts by mass of Bernock NC-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7 mass%, nonvolatile content 40 mass%) A film substrate layer (A-2) was obtained in the same manner as in Production Example 1 except that the two-component curable composition obtained by mixing was used.

[Production Example 3]
25.0 parts by mass of polyoxypropylene glycol having a number average molecular weight of 2000, polyester having a number average molecular weight of 2000 obtained by reacting a polyol obtained by adding 6 mol of propylene oxide to bisphenol A, sebacic acid and isophthalic acid 20.0 parts by mass of a polyol, 13.0 parts by mass of a polyester polyol having a number average molecular weight of 1000 obtained by reacting 1,4-butanediol and adipic acid, and diethylene glycol and o-phthalic acid were reacted. 13.0 parts by mass of the obtained polyester polyol having a number average molecular weight of 1000 was diluted 1.7 times with methyl ethyl ketone.

  Next, 11.0 parts by mass of 4,4′-diphenylmethane diisocyanate is mixed with the diluted product and reacted at 80 ° C. for 3 hours to obtain a polyurethane solution having a hydroxyl group (nonvolatile content 50% by mass, 25 ° C. Viscosity of 1000 mPa · s) was obtained.

  The polyurethane solution having the hydroxyl group and 3.7 parts by mass of Bernock NC-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass) A film substrate layer (A-3) was obtained in the same manner as in Production Example 1 except that the two-component curable composition obtained by mixing was used.

[Preparation Example 1]
In addition to the above, in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 80.94 parts by mass of n-butyl acrylate, 5 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of cyclohexyl acrylate, acrylic acid 4 parts by mass, 0.06 part by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate were charged, and the temperature was raised to 72 ° C. while blowing nitrogen under stirring.

  Next, 2 parts by mass of a 2,2′-azobis (2-methylbutyronitrile) solution previously dissolved in ethyl acetate (solid content: 0.1% by mass) was added to the mixture, and the mixture was stirred at 72 ° C. After holding for 4 hours, it was held at 75 ° C. for 5 hours.

  Next, the mixture was diluted with 98 parts by mass of ethyl acetate and filtered through a 200 mesh wire netting to obtain an acrylic polymer (B-1) solution (nonvolatile content: 40% by mass) having a weight average molecular weight of 1,600,000.

In addition, the said weight average molecular weight is a weight average molecular weight in standard polystyrene conversion measured by a gel permeation chromatograph (GPC), and was measured with the following method.
The measurement of the molecular weight by GPC method is a standard polystyrene conversion value measured using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation.

Sample concentration: 0.5% by mass (tetrahydrofuran solution)
Sample injection volume: 100 μl
Eluent: THF (tetrahydrofuran)
Flow rate: 1.0 ml / min Measurement temperature: 40 ° C
This column: TSKgel GMHHR-H (20) 2 Guard column: TSKgel HXL-H
Detector: differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (manufactured by Tosoh Corporation)
In a container, 5 parts by mass of D-125 (manufactured by Arakawa Chemical Co., Ltd.), which is a polymerized rosin ester-based tackifier resin, and petroleum-based tackifier resin with respect to 100 parts by mass of the acrylic polymer (B-1) After mixing and stirring 10 parts by mass of FTR6125 (Mitsui Chemicals Co., Ltd.), ethyl acetate was added to obtain an adhesive solution having a solid content of 31% by mass.

  Next, Vernock NC-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass with respect to 100 parts by mass of the adhesive solution. ) After adding 1.3 parts by mass, stirring and mixing so as to be uniform, the mixture was filtered through a 100 mesh wire net to obtain an adhesive (B-1).

[Preparation Example 2]
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 93.4 parts by mass of n-butyl acrylate, 3.5 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate, 2-hydroxy 0.1 parts by mass of ethyl acrylate and 0.1 part by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator are dissolved in 100 parts by mass of ethyl acetate, polymerized at 70 ° C. for 12 hours, An acrylic copolymer solution having an average molecular weight of 1.6 million was obtained.

  Next, with respect to 100 parts by mass of the acrylic copolymer solution, 9.4 parts by mass of “Superester A100” (glycerin ester of disproportionated rosin) manufactured by Arakawa Chemical Co., Ltd. and “Halitac” manufactured by Harima Chemicals Co., Ltd. PCJ "(pentaerythritol ester of polymerized rosin) 9.4 parts by mass was added, and ethyl acetate was added and mixed uniformly to obtain an adhesive composition having a nonvolatile content of 38% by mass.

  Next, Vernock NC-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass with respect to 100 parts by mass of the adhesive solution. ) 1.24 parts by mass was added, and the mixture was stirred and mixed to be uniform, and then filtered through a 100 mesh wire net to obtain an adhesive (B-2).

[Example 1]
The pressure-sensitive adhesive (B-1) is coated on the release-treated surface of the release sheet so that the thickness of the pressure-sensitive adhesive layer after drying is 75 μm and dried at 90 ° C. for 3 minutes. Two pieces of (B-1) were produced.

  Next, the pressure-sensitive adhesive layer (B-1) is attached to both surfaces of the film base layer (A-1) one by one, and the surface is reciprocated once using a roll having a linear pressure of 5 kg / cm. They were laminated. Next, the laminated product was aged in an environment of 40 ° C. for 48 hours to obtain a double-sided pressure-sensitive adhesive tape having a thickness of 250 μm.

[Example 2]
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive (B-2) was used instead of the pressure-sensitive adhesive (B-1).

[Comparative Example 1]
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the film base material layer (A-2) was used instead of the film base material layer (A-1).

[Comparative Example 2]
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the film base material layer (A-3) was used instead of the film base material layer (A-1).

[Method for measuring tensile elongation at break and tensile strength of film substrate layer]
The film base material layer obtained in the production example was cut into a rectangle having a length of 5 mm and a width of 1 mm using a cutter knife as a test piece. The both sides 1.5 mm on the long side of the test piece were sandwiched between air jaws of a tensile tester, pulled at 300 mm / min, and measured for elongation and strength until the film base material layer was broken.

[Processing evaluation method]
The double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were cut into a 1 mm wide strip using a cutter knife. At that time, the double-sided adhesive tape that could be cut into a 1 mm width with a substantially uniform width at both ends of the strip-shaped adhesive tape was evaluated as workability “◯”, and wrinkles occurred during the cutting, or the strip-shaped adhesive tape. A tape having a non-uniform width at both ends of the tape (with a difference of about 0.3 mm) was evaluated as a possibility “x”.

[Followability evaluation method]
The double-sided pressure-sensitive adhesive tapes obtained in the examples and comparative examples were cut into a frame shape having a width of 2 mm with an outer diameter of 64 mm × 43 mm, and this was adhered to an acrylic plate having a thickness of 2 mm and an outer diameter of 65 mm × 45 mm, An acrylic board with a tape was obtained.

  Next, a single-sided pressure-sensitive adhesive tape (thickness 30 μm, width 5 mm and length 45 mm) having an adhesive layer on one side of a polyethylene terephthalate base material at the center of an acrylic plate having a thickness of 2 mm and an outer shape 65 mm × 45 mm different from the above 2) Acrylic plates having a stepped portion were prepared by sticking two pieces in parallel in the longitudinal direction at intervals of 1 cm.

At 23 ° C., the surface having the step portion of the acrylic plate having the step portion is placed on the surface having the pressure-sensitive adhesive layer of the acrylic plate with the frame adhesive tape, and the upper portion thereof is pressed once and again at 30 N / cm ^2. Thus, a laminate was obtained.

  The followability of the pressure-sensitive adhesive sheet with respect to the step portion was visually evaluated from the acrylic plate side having the step portion constituting the laminate.

  A: No voids such as bubbles were observed at the interface between the stepped portion and the adhesive tape.

  (Triangle | delta): The space | gap, such as a fine bubble, was confirmed in the interface of a level | step-difference part and an adhesive tape.

  X: A clear void such as a large bubble was observed at the interface between the step portion and the adhesive tape.

[Measurement method of push strength]
A rectangular acrylic plate (Mitsubishi Rayon Co., Ltd. Acrylite MR200 “trademark”, hue: transparent) having a thickness of 2 mm and an outer diameter of 65 mm × 45 mm in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH. A frame-shaped pressure-sensitive adhesive tape having a width of 1.0 mm and a width of pressure-sensitive adhesive sheet of 1.0 mm was attached.

Next, an acrylic plate with an adhesive tape is attached to a rectangular stainless steel plate having a diameter of 8 mm in the center and a thickness of 2 mm and an outer shape of 65 mm × 30 mm, and then 50 N / cm ^2. Was subjected to pressure bonding for 10 seconds, and allowed to stand for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH, which was used as a test piece.

  From the stainless steel plate side of the test piece, the acrylic plate was pushed at 10 mm / min with a tensile tester equipped with a stainless steel probe having a diameter of 8 mm through a hole in the stainless steel plate, and the strength at which the acrylic plate was peeled was measured.

[Measuring method of static load holding force]
In an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%, one adhesive layer of a frame-shaped adhesive tape having an outer shape of 14 mm × 14 mm and an adhesive tape width of 1.0 mm is attached to an acrylic plate having a thickness of 2 mm and an outer shape of 15 mm × 15 mm. Attached to Mitsubishi Rayon Co., Ltd. Acrylite MR200 “trademark”, hue: transparent.

Next, an acrylic plate with an adhesive tape is attached to a rectangular stainless steel plate having a diameter of 8 mm in the center and a thickness of 2 mm and an outer shape of 65 mm × 30 mm, and then 50 N / cm ^2. The test piece was pressed for 10 seconds.

  In an atmosphere of a temperature of 40 ° C. and a relative humidity of 50%, the test piece was leveled so that the acrylic plate side was down, and both ends on the short side of the stainless steel plate were fixed. Next, a 200 g weight was attached to the center of the acrylic plate, and the acrylic plate was left in a state of being loaded downward.

  Next, in an atmosphere at a temperature of 40 ° C. and a relative humidity of 50%, the time (minutes) until the distance between the acrylic plate attached with the weight and the stainless steel plate is 0.2 mm apart from before the start of the test is measured. did. In addition, even if 24 hours passed from the start of measurement, an increase in the distance between the acrylic plate and the stainless steel plate was less than 0.2 mm was described as “1440 minutes or more” in the table described later.

[Impact resistance evaluation method]
By cutting the double-sided adhesive tape in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH, two adhesive tapes having a width of 5 mm and a length of 400 mm were produced.

  Next, the two adhesive tapes are placed on one side of an acrylic plate (Mitsubishi Rayon Co., Ltd. Acrylite MR200 “trademark”, hue: transparent) having a thickness of 2 mm, a width of 50 mm, and a length of 50 mm. Attached so that a space of 45 mm could be taken (see FIG. 1).

  Next, an acrylonitrile butadiene styrene plate (ABS plate, thickness 2 mm, width 100 mm and length 150 mm) was placed on the surface of the adhesive tape, and the surface was reciprocated once with a 5 kg roller, then at 23 ° C. and relative The test piece was obtained by leaving still for 24 hours in the environment of humidity 50% RH.

  Next, a U-shaped measuring table (made of aluminum with a thickness of 5 mm) having a length of 150 mm, a width of 100 mm, and a height of 45 mm was installed on the base of a DuPont impact tester (manufactured by Tester Sangyo Co., Ltd.). Above, the said test piece was installed so that the acrylic board which comprises it might face down.

  Next, a stainless steel hitting core having a diameter of 25 mm and a mass of 300 g was dropped from the ABS plate side five times from a position having a height of 10 cm.

  The above test was repeated while increasing the drop height by 10 cm, and the impact resistance of the adhesive tape was determined based on the drop height (cm) when peeling of the adhesive tape or separation of the acrylic plate was confirmed. evaluated.

  A: The drop height was 70 cm or more.

  ○: The drop height was 60 cm or more and less than 70 cm.

  Δ: The drop height was 40 cm or more and less than 60 cm.

  X: The drop height was less than 40 cm.

[Insulation evaluation method]
Two electrodes made of a rectangular copper foil with a thickness of 30 μm × length 5 cm × width 5 cm were attached to the surface of a smooth acrylic plate using an adhesive tape at a position where the distance between the electrodes was 1 mm.

  Next, a test tape obtained by cutting the double-sided adhesive tape obtained in Examples and Comparative Examples into a rectangle having a width of 0.7 mm and a length of 50 mm is attached between the two electrodes, and the upper surface of the test tape is attached. In addition, a test piece was obtained by curing a sample with an acrylic plate different from the above in an environment of 23 ° C. and 50% RH for 24 hours.

  Next, the discharge terminal of the electrostatic discharge tester was brought into contact with one of the electrodes, and discharged at a discharge voltage of 4 kV and an applied voltage of 10 times.

  The same test as above except that the discharge voltage is increased by 1 kV is repeated until the discharge to the other grounded electrode is confirmed. Based on the discharge voltage (kV) when the discharge is confirmed, The insulating property of the adhesive tape was evaluated.

  A: The discharge voltage was 12 kV or more.

  A: The discharge voltage was 10 kV or more and less than 12 kV.

  Δ: The discharge voltage was 7 kV or more and less than 10 kV.

  X: The discharge voltage was less than 7 kV.

DESCRIPTION OF SYMBOLS 1 Acrylic board 2 One electrode 3 The other electrode 4 Test tape 5 Acrylic board 6 Discharge terminal

Claims (10)

At least one surface side of the film substrate (A) having a tensile breaking elongation measured by pulling at a pulling speed of 300 mm / min is 450% or more and a tensile breaking strength is 2000 N / cm ² or more, An adhesive tape having an adhesive layer (B). The pressure-sensitive adhesive tape according to claim 1, having a total thickness of 300 µm or less. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the film base (A) is a polyurethane base having a thickness of 200 µm or less. The adhesive tape of any one of Claims 1-3 used for fixation of an electronic component. The pressure-sensitive adhesive tape according to claim 4, wherein the electronic component is a case, a lens member, a rechargeable battery, a circuit board, or an information display panel. The waterproof tape which consists of an adhesive tape of any one of Claims 1-5. The electric discharge prevention tape which consists of an adhesive tape of any one of Claims 1-5. Tensile rupture measured by pulling at a pulling speed of 300 mm / min by coating and drying a two-component curable composition containing a hydroxyl group-containing polyurethane and polyisocyanate on the surface of the release liner Step [1] of producing a film substrate (A) having an elongation of 450% or more and a tensile breaking strength of 2000 N / cm ² or more, and applying an adhesive to the surface of a release liner different from the above The step [2] of forming the pressure-sensitive adhesive layer (B) by coating, and the step [3] of transferring the pressure-sensitive adhesive layer (B) to at least one surface side of the film substrate (A). A method for producing an adhesive tape, comprising: An article having a configuration in which two or more adherends are bonded by the pressure-sensitive adhesive tape according to any one of claims 1 to 5. A portable electronic terminal having a configuration in which two or more casings, or a casing and a lens member are bonded by the adhesive tape according to claim 1.

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