JP2018111744A - Adhesive body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive body of removable type that can maintain sufficient adhesive power even in contact with oil.SOLUTION: An adhesive film 10 has a base material 1, and an adhesive layer 2 of removable type that contains an adhesive and an oil absorbing material configured to absorb oil. The adhesive 2 contains, as the oil absorbing material, a porous body. The porous body is preferably porous silica. Relative to the adhesive 100 pts.mass, the content of the oil absorbing material is preferably 0.1 pts.mass or more and 50 pts.mass or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive body.

  A pressure-sensitive adhesive film having a re-peelable pressure-sensitive adhesive layer (re-peelable pressure-sensitive adhesive film) is easy to handle, and is used for various labels, lids, and the like (for example, see Patent Document 1).

  However, the conventional re-peelable pressure-sensitive adhesive film has a problem that when oil comes into contact with the pressure-sensitive adhesive layer, the adhesive force to the adherend is significantly reduced.

JP 2013-241614 A

  An object of the present invention is to provide a re-peelable pressure-sensitive adhesive body that can maintain a sufficient adhesive force even when contacted with oil.

Such an object is achieved by the present invention described in the following (1) to (5).
(1) a base material;
A re-peelable pressure-sensitive adhesive layer containing an adhesive and an oil absorbent having a function of absorbing oil;
A pressure-sensitive adhesive body comprising a porous body as the oil absorbing material.
(2) The pressure-sensitive adhesive body according to (1), wherein the porous body is porous silica.

  (3) The pressure-sensitive adhesive body according to the above (1) or (2), wherein the content of the oil absorbent relative to 100 parts by weight of the pressure-sensitive adhesive is from 0.1 parts by weight to 50 parts by weight.

  (4) The pressure-sensitive adhesive according to any one of (1) to (3), wherein the pressure-sensitive adhesive includes a monomer having an aliphatic hydrocarbon group having 5 or more carbon atoms as a constituent component.

  (5) The pressure-sensitive adhesive body according to any one of (1) to (4), wherein the pressure-sensitive adhesive layer further includes a plasticizer having an alkylene group having 4 or more carbon atoms in the molecule.

  ADVANTAGE OF THE INVENTION According to this invention, the re-peelable adhesive body which can maintain sufficient adhesive force even when it contacts oil can be provided.

It is a typical longitudinal section showing a suitable embodiment of an adhesion object (adhesion film) of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Re-peelable pressure-sensitive adhesive composition]
First, the re-peelable pressure-sensitive adhesive composition that can be suitably used for producing the pressure-sensitive adhesive body of the present invention will be described.

  In the present invention, the “re-peeling type” refers to a material that can be repeatedly stuck to and peeled from an adherend.

  The re-peelable pressure-sensitive adhesive composition is used for forming a pressure-sensitive adhesive layer of a re-peelable pressure-sensitive adhesive body.

  The re-peelable pressure-sensitive adhesive composition of the present embodiment includes a pressure-sensitive adhesive and an oil absorbent having a function of absorbing oil. The re-peelable pressure-sensitive adhesive composition of this embodiment includes a porous body as an oil absorbent.

  Thus, by including the oil absorbent, when the pressure-sensitive adhesive layer formed using the re-peelable pressure-sensitive adhesive composition comes into contact with the oil, the oil is efficiently absorbed and retained, and the adherend and The amount of oil present on the contact surface can be reduced. In particular, by including a porous body as the oil absorbing material, oil can be taken into the oil absorbing material and kept in a favorable state with particularly high efficiency. As a result, even when it is in contact with oil, the adhesive force to the adherend can be suitably maintained.

  Examples of the oil include hydrocarbons having 5 or more carbon atoms, fatty acids having 5 or more carbon atoms, and ester compounds thereof (including fats and oils such as esters with polyhydric alcohols such as glycerin (for example, triglycerides)), Various silicone oils (for example, methicone, cyclomethicone, etc.) can be mentioned.

  In addition to mineral oil and synthetic oil, the oil includes vegetable oil such as olive oil, sesame oil and jojoba oil, animal oil such as fish oil and lard.

Examples of the pressure-sensitive adhesive contained in the re-peelable pressure-sensitive adhesive composition include acrylic, synthetic rubber and natural rubber, and acrylic pressure-sensitive adhesive is preferred.
Thereby, the adhesiveness with respect to a to-be-adhered body can be made more excellent.

  The acrylic pressure-sensitive adhesive is acrylic acid, methacrylic acid (hereinafter collectively referred to as “(meth) acrylic acid”) or ester compounds thereof (acrylate, methacrylate (hereinafter collectively referred to as “meth (acrylate)”). It is also expressed as “)”. A copolymer containing a (meth) acrylic acid derivative such as)) as a monomer component is preferable. Moreover, you may contain monomer components other than the above.

  The pressure-sensitive adhesive preferably contains a monomer having an aliphatic hydrocarbon group having 5 or more carbon atoms as a constituent component.

  Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including an oil absorbing material that will be described in detail later, the absorbed oil can be more suitably held inside, and the adhesive holding effect when contacting the oil is more excellent. can do. In addition, the affinity between the pressure-sensitive adhesive and the oil absorbing material can be made more excellent, and in the re-peelable pressure-sensitive adhesive composition, unintentional compositional variation in the pressure-sensitive adhesive layer can be prevented more effectively. And a more stable oil absorption function is exhibited at each part.

As described above, the pressure-sensitive adhesive preferably contains a monomer having an aliphatic hydrocarbon group having 5 or more carbon atoms as a constituent component, but the aliphatic hydrocarbon group has 6 or more carbon atoms. More preferably, it is 8 or more and 16 or less.
Thereby, the effects as described above are more remarkably exhibited.

The aliphatic hydrocarbon group may have a cyclic structure or a branched chain structure, but preferably has a linear structure.
Thereby, the effects as described above are more remarkably exhibited.

The proportion of the monomer having an aliphatic hydrocarbon group in the molecule (polymer) constituting the pressure-sensitive adhesive is preferably 50% by mass or more, and more preferably 60% by mass or more.
Thereby, the effects as described above are more remarkably exhibited.

  Examples of the monomer component constituting the acrylic pressure-sensitive adhesive include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and decyl (meth). Examples include acrylate and tetradecyl (meth) acrylate.

  Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including an oil absorbing material that will be described in detail later, the absorbed oil can be more suitably held inside, and the adhesive holding effect when contacting the oil is more excellent. can do. In addition, the affinity between the pressure-sensitive adhesive and the oil absorbing material can be made more excellent, and in the re-peelable pressure-sensitive adhesive composition, unintentional compositional variation in the pressure-sensitive adhesive layer can be prevented more effectively. And a more stable oil absorption function is exhibited at each part.

  It is preferable that the content of the monomer having a polar group (for example, a hydroxyl group, a carboxyl group, an amino group, or a salt thereof) in the molecule (polymer) of the acrylic pressure-sensitive adhesive is sufficiently low.

  More specifically, the content of the monomer having a polar group in the molecule (polymer) of the acrylic pressure-sensitive adhesive is preferably 10% by mass or less, and more preferably 5% by mass or less.

Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including an oil absorbing material that will be described in detail later, the absorbed oil can be more suitably held inside, and the adhesive holding effect when contacting the oil is more excellent. can do.
As the adhesive, either a solvent type or an emulsion type may be used.

  The re-peelable pressure-sensitive adhesive composition preferably contains a cross-linked pressure-sensitive adhesive crosslinked with a cross-linking agent as the pressure-sensitive adhesive.

  Thereby, the cohesive force of an adhesive layer can be made more excellent and the adhesive residue at the time of peeling from a to-be-adhered body can be prevented more effectively.

  Examples of the crosslinking agent include aliphatic isocyanate compounds, aromatic isocyanate compounds, epoxy compounds, metal chelate compounds, aziridine compounds and other polyimine compounds, melamine resins, urea resins, dialdehydes, methylol polymers, metal alkoxides, metal salts. Etc. can be used. More specifically, for example, hexamethylene diisocyanate (HMDI) or an aliphatic isocyanate compound which is a derivative thereof, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, N, N, N ′, Epoxy compounds such as N′-tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N-diglycidylaminomethyl) toluene And metal chelate compounds such as aluminum chelate compounds such as aluminum-isopropylate, aluminum-sec butyrate and aluminum acetylacetonate, and titanium chelate compounds such as tetraisopropyl titanate and tetrakis (2-ethylhexoxy) titanate.

  The amount of the crosslinking agent is not particularly limited, but is preferably 0.01 parts by mass or more and 2.0 parts by mass or less, and 0.03 parts by mass or more and 1.0 parts by mass with respect to 100 parts by mass of the polymer component of the adhesive main agent. More preferably, the amount is 0.05 parts by mass or more and 0.5 parts by mass or less.

  As a result, a more suitable adhesive force capable of performing re-peeling more appropriately is obtained, and the occurrence of a problem of adhesive residue can be more effectively prevented.

  The oil absorbing material has a function of absorbing oil and taking oil that has come into contact with the pressure-sensitive adhesive layer into the pressure-sensitive adhesive layer, or a function of holding oil in the pressure-sensitive adhesive layer.

  By including such an oil absorber, the amount of oil on the surface of the pressure-sensitive adhesive layer can be reduced when the pressure-sensitive adhesive layer comes into contact with oil, and the adhesion (adhesive strength) to the adherend is suitably Can be maintained.

  In particular, a porous body is included as an oil absorbing material. As a result, the oil can be taken into the oil absorbing material with high efficiency, and the state can be suitably maintained.

  The porosity of the porous body is not particularly limited, but is preferably 10% by volume or more and 80% by volume or less, and more preferably 15% by volume or more and 70% by volume or less.

  As a result, more oil can be absorbed, the mechanical strength of the porous body can be improved, and the oil that has been absorbed more stably can be retained.

The porous body is preferably particulate.
When the porous body is in the form of particles as an aggregate, the average particle size (secondary particle diameter) of the porous body is preferably 0.1 μm or more and 30 μm or less, and 1.0 μm or more and 15 μm or less. It is more preferable that

  As a result, the dispersion stability and coating properties of the porous material in the re-peelable pressure-sensitive adhesive composition are excellent, and the occurrence of unintentional irregularities on the surface of the pressure-sensitive adhesive layer to be formed is more effectively achieved. Can be prevented.

  In this specification, the average particle diameter means a volume-based average particle diameter unless otherwise specified. For example, a dispersion liquid of a target particle is measured using a Coulter Counter particle size distribution measuring instrument (manufactured by COULTER ELECTRONICS INC). TA-II type etc.) and can be obtained by measuring using a 50 μm aperture.

  As a constituent material of the porous body, for example, calcium silicate, calcium carbonate, diatomaceous earth, silicon dioxide (silica), aluminum oxide (alumina), montmorillonite, kaolin and other clay minerals, various glasses, various metals, salt, etc. Inorganic compounds, low molecular organic compounds such as calcium lactate and lactose, starches such as dextrin, processed starch and porous starch, cellulose derivatives such as crystalline cellulose, methylcellulose and cellulose ether compounds, and polyvinyl alcohol.

  In particular, the porous body is preferably porous silica. Thereby, oil can be absorbed and held more efficiently. In addition, porous silica is advantageous from the viewpoint of the stability of the shape of the pressure-sensitive adhesive layer and the like because it has a small thermal expansion coefficient and a small volume change due to oil absorption. In addition, since porous silica is easily available and relatively inexpensive among various porous bodies, it is advantageous from the viewpoints of stable production and supply of the pressure-sensitive adhesive, and suppression of manufacturing costs.

  The porous body may be subjected to a surface treatment such as a hydrophobization treatment (lipophilic treatment).

  Thereby, the affinity between the porous body and the oil is improved, and the porous body can absorb the oil with higher efficiency.

In particular, in the case of a porous body, it is preferable that the inner wall surfaces of the pores are subjected to a hydrophobic treatment.
Thereby, the effect mentioned above is exhibited more notably.

Examples of the hydrophobic treatment include a method of treating with a coupling agent such as a silane coupling agent and a titanate coupling agent, a metal soap treatment method using a zinc salt, a magnesium salt or an aluminum salt of a fatty acid. .
Moreover, you may use combining multiple types of porous bodies.

  As the oil absorbing material, at least a porous material may be used, but an oil absorbing material other than the porous material may be used in combination.

  Examples of the oil absorbing material other than the porous material include a gelling agent that swells and gels by absorbing oil.

  In particular, when a plurality of types of oil absorbing materials having different action mechanisms are included, the above-described effects become more remarkable. More specifically, for example, as an oil absorber, a component that mainly contributes to rapid oil absorption, and a component that has a function of storing oil absorbed in the pressure-sensitive adhesive layer (for example, a porous body) In the case of containing oil, it is possible to achieve both rapid oil absorption and prevention of oil bleed out over a long period of time by transferring the oil between these components, and excellent effects are stable over a long period of time. Is obtained.

  Although the content rate of the oil absorber contained in a re-peeling-type adhesive composition is not specifically limited, It is preferable that it is 0.1 mass part or more and 50 mass parts or less with respect to 100 mass parts of adhesives, 1 mass More preferably, it is more than 30 parts by mass and more preferably less than 5 parts by mass and less than 20 parts by mass.

  If the content of the oil absorbent is too low, the effects of including the oil absorbent as described above may not be sufficiently exhibited depending on the type of the oil absorbent. Moreover, when the content rate of an oil absorber is too high, the content rate of an adhesive will fall relatively and the function of an adhesive may not fully be exhibited.

The re-peelable pressure-sensitive adhesive composition may contain a plasticizer.
Thereby, the softness | flexibility and elasticity of a re-peelable adhesive composition can be made more excellent. Moreover, the releasability of the pressure-sensitive adhesive layer formed using the re-peelable pressure-sensitive adhesive composition can be made more excellent, and a pressure-sensitive adhesive body produced using the re-peelable pressure-sensitive adhesive composition (for example, , The adhesive feeling when the adhesive film is peeled from the adherend can be made more excellent.

  Examples of plasticizers include phthalate plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n-octyl phthalate, and dicyclohexyl phthalate, trioctyl trimellitic acid, and trimellitic acid. Trimellitonate plasticizers such as triisononyl acid, triisodecyl trimellitic acid, 2-ethylhexyl trimellitic acid, polyester plasticizers such as phthalic acid polyester, phosphorus such as tricresyl phosphate, trioctyl phosphate, triphenyl phosphate Examples include acid ester plasticizers, epoxidized linseed oil, and epoxy plasticizers such as epoxidized butyl stearate, and those having an alkylene group having 4 or more carbon atoms in the molecule are preferred.

  Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including the oil absorbing material, the absorbed oil can be more suitably held inside, and the holding effect of the adhesive strength when in contact with the oil can be further improved. . Moreover, the affinity between the plasticizer and the oil absorbing material, and the affinity between the plasticizer and the pressure-sensitive adhesive (particularly pressure-sensitive adhesive having a suitable chemical structure as described above) can be further improved. In the re-peelable pressure-sensitive adhesive composition, it is possible to more effectively prevent unintended compositional variations in the pressure-sensitive adhesive layer, and a more stable oil absorbing function is exhibited at each site.

  Moreover, as a plasticizer, it is preferable to use what does not have an aromatic ring structure in a molecule | numerator.

  Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including the oil absorbing material, the absorbed oil can be more suitably held inside, and the holding effect of the adhesive strength when in contact with the oil can be further improved. . Moreover, the affinity between the plasticizer and the oil absorbing material, and the affinity between the plasticizer and the pressure-sensitive adhesive (particularly pressure-sensitive adhesive having a suitable chemical structure as described above) can be further improved. In the re-peelable pressure-sensitive adhesive composition, it is possible to more effectively prevent unintended compositional variations in the pressure-sensitive adhesive layer, and a more stable oil absorbing function is exhibited at each site.

  When the plasticizer is an ester compound of a polyvalent carboxylic acid component and an alcohol component, the alcohol component preferably has an alkyl group having 8 or more carbon atoms.

  Thereby, the lipophilicity as the whole re-peelable pressure-sensitive adhesive composition (the whole pressure-sensitive adhesive layer) becomes more excellent. As a result, coupled with the effect of including the oil absorbing material, the absorbed oil can be more suitably held inside, and the holding effect of the adhesive strength when in contact with the oil can be further improved. . Moreover, the affinity between the plasticizer and the oil absorbing material, and the affinity between the plasticizer and the pressure-sensitive adhesive (particularly pressure-sensitive adhesive having a suitable chemical structure as described above) can be further improved. In the re-peelable pressure-sensitive adhesive composition, it is possible to more effectively prevent unintended compositional variations in the pressure-sensitive adhesive layer, and a more stable oil absorbing function is exhibited at each site.

  Examples of the plasticizer that satisfies the above conditions include those having a chemical structure represented by the following formula (2) and the following formula (3).

（ただし、式（２）中、ｍは４以上の整数、ｌは８以上の整数を示す。）

(In the formula (2), m represents an integer of 4 or more, and l represents an integer of 8 or more.)

（ただし、式（３）中、ｌは８以上の整数を示す。）

(In the formula (3), l represents an integer of 8 or more.)

  By using such a plasticizer, the lipophilicity as the entire re-peelable pressure-sensitive adhesive composition (entire pressure-sensitive adhesive layer) is further improved. As a result, coupled with the effect of including the oil absorbing material, the absorbed oil can be more suitably held inside, and the holding effect of the adhesive strength when in contact with the oil can be further improved. . Further, the affinity between the plasticizer and the oil absorbing material, and the affinity between the plasticizer and the pressure-sensitive adhesive (particularly pressure-sensitive adhesive having a suitable chemical structure as described above) can be further improved. In the re-peelable pressure-sensitive adhesive composition, it is possible to more effectively prevent unintended compositional variations in the pressure-sensitive adhesive layer, and a more stable oil absorbing function is exhibited at each site.

  Such an effect is obtained by using at least one of the plasticizer having the chemical structure represented by the above formula (2) and the plasticizer having the chemical structure represented by the above formula (3) as the fat having 5 or more carbon atoms. This is more remarkable when used in combination with a pressure-sensitive adhesive containing a monomer having an aromatic hydrocarbon group as a constituent component.

  Although the content rate of the plasticizer contained in the re-peelable pressure-sensitive adhesive composition is not particularly limited, it is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the adhesive, and 5 parts by mass or more and 25 parts by mass. It is more preferable that the amount is not more than part by mass.

  If the content of the plasticizer is too low, the effect of including the plasticizer as described above may not be sufficiently exhibited depending on the type of the plasticizer. Moreover, when the content rate of a plasticizer is too high, the content rate of an adhesive will fall relatively and the function of an adhesive may not fully be exhibited.

  The re-peelable pressure-sensitive adhesive composition may contain components other than those described above. Examples of such components include various resins, curing catalysts, solvents, softeners, dyes, pigments and other colorants, anilide-based and phenol-based antioxidants, benzophenone-based, benzotriazole-based UV absorbers, and the like. , Light stabilizers, dispersants, leveling agents, antistatic agents and the like. The content of these components is not particularly limited, but it is preferable not to exceed 10% by mass as a whole of these components excluding the solvent.

[Adhesive]
Next, the pressure-sensitive adhesive body of the present invention will be described.

  FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the pressure-sensitive adhesive body (pressure-sensitive adhesive film) of the present invention.

  As shown in FIG. 1, an adhesive film (removable adhesive film) 10 as an adhesive body includes a substrate 1 and a removable adhesive layer 2. And the adhesive layer 2 is comprised with the material containing an adhesive and the oil absorber which has a function which absorbs oil. And the adhesive layer 2 contains a porous body as an oil absorber.

Thereby, even when the adhesive film 10 (particularly, the adhesive layer 2) is in contact with oil, sufficient adhesive force and re-adhesiveness to the adherend can be maintained.
In the present specification, the “adhesive film” includes the concept of an adhesive sheet, an adhesive tape, and an adhesive label.

The substrate 1 has a function of supporting the pressure-sensitive adhesive layer 2.
The substrate 1 may be in any form such as a dense body, a woven fabric, a nonwoven fabric, paper, a porous body, a synthetic paper such as polypropylene and polyester, and a foamed body.

  The constituent material of the substrate 1 is not particularly limited, and examples thereof include resin materials, metal materials, vegetable fibers such as pulp, animal fibers such as wool, and the like, and resin materials are preferably used.

  Examples of the resin material constituting the substrate 1 include polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, Polyolefins such as ethylene / butyl acrylate copolymer, ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate; acetate resin, acrylonitrile -Butadiene-styrene copolymer (ABS) resin, polystyrene, polyvinyl chloride, polyamide, polyesteramide, polyether, polyimide, polyamideimide, poly-p-phenylene sulfide, polyether s Le, and the like, may be used alone or in combination of two or more selected from these. Further, as the substrate 1, for example, a substrate provided with a metal film formed by a vapor deposition method or the like may be used. Examples of the metal include aluminum.

  Moreover, the base material 1 may contain components other than those described above. Examples of such components include colorants such as dyes and pigments, antioxidants such as anilides and phenols, UV absorbers such as benzophenones and benzotriazoles, light stabilizers, modifiers, and rust prevention. Agents, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, crosslinking agents, catalysts, plasticizers, leveling agents, thickeners, softeners, dispersants, etc. It is done.

  Moreover, the base material 1 may be comprised from a single layer, and the laminated body provided with a some layer may be sufficient as it. Moreover, the base material 1 may be comprised with the inclination material from which a composition changes in gradient in the thickness direction, for example.

  Moreover, the base material 1 may have a primer layer for improving the adhesiveness with the pressure-sensitive adhesive layer 2. Examples of the primer layer include acrylic, olefin, polyester, and polyurethane.

  Thereby, with respect to the adhesive force between the adhesive layer 2 and the adherend, the adhesive force between the substrate 1 and the adhesive layer 2 can be made particularly large, and the adhesive film 10 can be removed from the adherend. It is possible to more effectively prevent the pressure-sensitive adhesive layer 2 from being peeled off from the substrate 1 and remaining on the adherend during peeling.

  Further, the base material 1 may be subjected to a surface treatment by, for example, an oxidation method or an unevenness method.

  Examples of the oxidation method include corona discharge treatment (corona treatment), chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like. Method, solvent treatment method and the like.

These surface treatment methods are appropriately selected according to the material constituting the substrate 1, but in general, corona treatment is preferable from the viewpoints of effects and operability.
Moreover, primer treatment can also be performed.

  Although the thickness of the base material 1 is not specifically limited, It is preferable that they are 15 micrometers or more and 300 micrometers or less, and it is more preferable that they are 20 micrometers or more and 50 micrometers or less.

  The pressure-sensitive adhesive layer 2 may be formed of a material including a pressure-sensitive adhesive and an oil absorbent having a function of absorbing oil, but is preferably formed by using the above-described re-peelable pressure-sensitive adhesive composition. can do.

  Although the content rate of the oil absorbent contained in the pressure-sensitive adhesive layer 2 is not particularly limited, it is preferably 0.1 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the pressure-sensitive adhesive. More preferably, it is 5 parts by mass or less and even more preferably 20 parts by mass or less.

  If the content of the oil absorbent is too low, the effects of including the oil absorbent as described above may not be sufficiently exhibited depending on the type of the oil absorbent. Moreover, when the content rate of an oil absorber is too high, the content rate of an adhesive will fall relatively and the function of an adhesive may not fully be exhibited.

  The thickness of the pressure-sensitive adhesive layer 2 is not particularly limited, but is preferably 1 μm or more and 100 μm or less, more preferably 3 μm or more and 50 μm or less, and further preferably 5 μm or more and 30 μm or less.

[Method for producing adhesive film]
Next, the manufacturing method of the adhesive film of this invention is demonstrated.

The base material 1 as described above is prepared.
And the adhesive layer 2 is formed. Although the formation method of the adhesive layer 2 is not specifically limited, It can form suitably by providing the re-peeling-type adhesive composition mentioned above on one side of the prepared base material 1. FIG.

Application of the re-peelable pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 2 includes, for example, a liquid re-peelable pressure-sensitive adhesive composition (coating liquid), roll coat, reverse coat, knife coat, die coat, and gravure. It can carry out by applying on the base material 1 by various coating methods such as coating and bar coating.
The adhesive layer 2 can be formed by drying the coating film of the coating liquid.

  The pressure-sensitive adhesive layer 2 may have a composition different from that of the re-peelable pressure-sensitive adhesive composition as a coating liquid. For example, after applying the re-peelable pressure-sensitive adhesive composition, the contained solvent may be removed, or the degree of polymerization and the degree of crosslinking may be different by advancing a curing reaction and a crosslinking reaction.

  In forming the pressure-sensitive adhesive layer 2, the re-peelable pressure-sensitive adhesive composition and other components may be mixed to adjust the coating liquid. For example, when the pressure-sensitive adhesive layer 2 is formed, the re-peelable pressure-sensitive adhesive composition and a solvent may be mixed.

  Examples of the solvent include ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone, and aromatic hydrocarbon solvents such as toluene and xylene, and the like. These can be used alone or in combination.

  The coating solution may be any coating solution, and the solid content concentration in the coating solution is not particularly limited, but is preferably 20% by mass or more and 70% by mass or less, and 25% by mass or more and 60% by mass or less. It is more preferable that

  The pressure-sensitive adhesive layer 2 may be once formed on a release liner and then bonded to the substrate 1.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to these.

  For example, the pressure-sensitive adhesive body (for example, a pressure-sensitive adhesive film) may have at least one intermediate layer between the base material and the pressure-sensitive adhesive layer.

  In addition, the pressure-sensitive adhesive body (for example, a pressure-sensitive adhesive film) may have at least one coating layer on the surface opposite to the surface facing the pressure-sensitive adhesive layer of the substrate. For example, the printed layer may be provided on the surface of the substrate opposite to the surface facing the pressure-sensitive adhesive layer. Moreover, in order to improve adhesiveness with a printing layer, the coating layer for printing etc. may be provided. Moreover, the coat layer which has functions, such as protecting the surface of an adhesive film, may be provided.

  Further, in the above-described embodiment, the case where the pressure-sensitive adhesive body is a pressure-sensitive adhesive film including a film-like base material and forming a film shape as the whole pressure-sensitive adhesive body has been representatively described. The shape is not limited to a film shape and may be any shape.

  Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples. In the following description, the treatment that does not particularly indicate the temperature condition is performed at room temperature (23 ° C.) and a relative humidity of 50%. Moreover, what does not show temperature conditions in particular also about various measurement conditions is a numerical value in room temperature (23 degreeC).

[1] Production of adhesive film (Example 1)
An acrylic copolymer (acrylic pressure-sensitive adhesive) having a monomer composition as shown in Table 1 and having a weight average molecular weight of 800,000, Tetrad C (manufactured by Mitsubishi Gas Chemical Company) as an epoxy-based crosslinking agent, A porous silica (manufactured by AGC S-Tech, Sunsphere H-33) as an oil absorbent (porous body), a compound represented by the following formula (4) as a plasticizer, and toluene as a solvent are mixed. Then, a pressure-sensitive adhesive composition (removable pressure-sensitive adhesive composition) as a coating solution was prepared.

  Next, the above-mentioned pressure-sensitive adhesive composition was coated on a release liner (release paper) made of glassine using a knife coater so that the thickness after drying was 25 μm.

Then, the solvent was removed by heating at 100 ° C. for 2 minutes to form an adhesive layer.
Next, a film-like base material made of polyethylene terephthalate having a thickness of 50 μm and having a corona treatment applied to the adhesive layer is bonded to the pressure-sensitive adhesive layer and aged for one week at a temperature of 23 ° C. and a relative humidity of 50%. By cross-linking the pressure-sensitive adhesive layer, a pressure-sensitive adhesive film in which the pressure-sensitive adhesive layer was protected with a release liner was obtained. The film thickness was measured with a micro gauge.

(Examples 2 to 4)
A pressure-sensitive adhesive film was produced in the same manner as in Example 1 except that the composition of the pressure-sensitive adhesive, the composition of the pressure-sensitive adhesive composition, and the structure of the pressure-sensitive adhesive film were as shown in Table 1.

(Comparative Example 1)
A pressure-sensitive adhesive film was produced in the same manner as in Example 1 except that the composition of the pressure-sensitive adhesive, the composition of the pressure-sensitive adhesive composition, and the structure of the pressure-sensitive adhesive film were as shown in Table 1.

  Table 1 shows the monomer composition of the pressure-sensitive adhesive (acrylic copolymer), the composition of the pressure-sensitive adhesive composition, and the structure of the pressure-sensitive adhesive film used in the production of the pressure-sensitive adhesive films of the above Examples and Comparative Examples.

  In Table 1, 2-ethylhexyl acrylate is M1, decyl acrylate is M2, tetradecyl acrylate is M3, butyl acrylate is M4, acrylic acid is M5, 2-hydroxyethyl acrylate is M6, tetrad-C is TC, Silica as a porous material (AGC S-Tech, Sunsphere H-33) is OA1, silica as a porous material (NIPSIL NS-T, manufactured by Tosoh Silica) is OA2, and methacrylic acid as a porous material A hollow porous spherical microparticle of methyl cross polymer (Matsumoto Yushi Seiyaku Co., Ltd., Matsumoto Microsphere MHB-R) is represented by OA3, a compound represented by the above formula (4) is represented by P1, and polyethylene terephthalate is represented by PET.

[2] Evaluation <Initial adhesive strength (adhesive strength when not in contact with oil)>
The pressure-sensitive adhesive films (pressure-sensitive adhesive films protected with a release liner) of each of the above examples and comparative examples were cut into a size of 25 mm wide × 150 mm long to obtain a test piece.

  The release liner was peeled from the obtained test piece, the exposed pressure-sensitive adhesive layer was brought into contact with the polyethylene terephthalate film, and the pressure-sensitive adhesive film (test piece) was brought into intimate contact with the 2 kg roll by one reciprocating pressure bonding.

  The adhesive strength was measured in a 180 ° peel test in which the sample was left for 24 hours and then peeled off at a rate of 300 mm / min in the 180 ° direction using a tensile tester, and evaluated according to the following criteria. The film with A evaluation is the optimum adhesive strength as a re-peelable adhesive film, and is in the order of B, C, D, and E, and deviates from the range of preferable adhesive strength.

A: Adhesive strength (initial adhesive strength) is 4 N / 25 mm or more and less than 7 N / 25 mm.
B: Adhesive strength (initial adhesive strength) is 3 N / 25 mm or more and less than 4 N / 25 mm (except for the range of A).
C: Adhesive strength (initial adhesive strength) is 2 N / 25 mm or more and less than 3 N / 25 mm (except for the range of A and B).
D: Adhesive strength (initial adhesive strength) is 1 N / 25 mm or more and less than 2 N / 25 mm (excluding ranges of A, B, and C).
E: Adhesive strength (initial adhesive strength) is less than 1 N / 25 mm or 7 N / 25 mm or more.

<Adhesive strength after contact with oil>
The pressure-sensitive adhesive films (pressure-sensitive adhesive films protected with a release liner) of each of the above examples and comparative examples were cut into a size of 25 mm wide × 150 mm long to obtain a test piece.

After applying cleansing oil containing mineral oil (mineral oil) and cyclomethicone (silicone oil) at 2 g / m ² on one surface of the polyethylene terephthalate film, the release liner was peeled from the test piece, and the exposed adhesive The agent layer was brought into contact and pressed in the same manner as described above.

  The adhesive strength was measured in a 180 ° peel test in which the sample was left for 24 hours and then peeled off at a rate of 300 mm / min in the 180 ° direction using a tensile tester, and evaluated according to the following criteria.

A: Adhesive strength (adhesive strength after oil contact) is 75% or more of initial adhesive strength.
B: Adhesive strength (adhesive strength after oil contact) is 50% or more and less than 75% of initial adhesive strength.
C: Adhesive strength (adhesive strength after oil contact) is 25% or more and less than 50% of initial adhesive strength.
D: Adhesive strength (adhesive strength after oil contact) is 10% or more and less than 25% of initial adhesive strength.
E: Adhesive strength (adhesive strength after oil contact) is less than 10% of initial adhesive strength.
These results are summarized in Table 2.

  As is apparent from Table 2, excellent results were obtained in the present invention, whereas satisfactory results were not obtained in the comparative example.

10 ... Adhesive film (removable adhesive film)
DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Adhesive layer

Claims (5)

A substrate;
A re-peelable pressure-sensitive adhesive layer containing an adhesive and an oil absorbent having a function of absorbing oil;
A pressure-sensitive adhesive body comprising a porous body as the oil absorbing material.   The pressure-sensitive adhesive body according to claim 1, wherein the porous body is porous silica.   The pressure-sensitive adhesive body according to claim 1 or 2, wherein the content of the oil absorbent relative to 100 parts by mass of the pressure-sensitive adhesive is 0.1 parts by mass or more and 50 parts by mass or less.   The pressure-sensitive adhesive according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive contains a monomer having an aliphatic hydrocarbon group having 5 or more carbon atoms as a constituent component.   The pressure-sensitive adhesive body according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer further contains a plasticizer having an alkylene group having 4 or more carbon atoms in the molecule.

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