JP7036623B2 - Laminate - Google Patents

Description

The present invention relates to a laminate. In particular, the present invention relates to a laminate having an adhesive layer.

Conventionally, adhesive tapes have been widely used when fixing parts in electronic devices. Specifically, for example, an adhesive tape is used to bond a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to bond a touch panel module to a display panel module. ing. The adhesive tape used for fixing such electronic device parts has, for example, an adhesive layer containing an acrylic adhesive, and has high adhesiveness and heat resistance depending on the environment of the part to be used. , Thermal conductivity, impact resistance and the like are required (for example, Patent Documents 1 to 3).

JP-A-2015-052050 Japanese Patent Application Laid-Open No. 2015-021067 JP-A-2015-120876

Especially in recent years, portable electronic devices have become widespread. These portable electronic devices are frequently used and are operated with bare hands using a touch panel or the like. For this reason, there is a problem that the sebum of the hand is transferred to the inside of the electronic device from the portion that is frequently touched by the hand, and the sebum reduces the adhesive strength of the adhesive tape and causes it to peel off. It is also expected that alcoholic beverages and the like will infiltrate the inside of electronic devices. For this reason, it is desired that the component fixing portions of these portable electronic devices are firmly adhered to each other, and that they are not easily deteriorated by sebum and alcohol and are not easily peeled off (resistance to sebum and alcohol).

In view of the above problems, it is an object of the present invention to provide a laminate that is firmly adhered and has resistance to sebum and alcohol.

In the present invention, the adherend, the primer layer and the pressure-sensitive adhesive layer are laminated in this order, and the pressure-sensitive adhesive layer contains 30% by weight or more and 70% by weight or less of a structural unit derived from a fluorine-containing (meth) acrylate. The primer layer contains an (meth) acrylate copolymer, and the primer layer is an amino group-containing poly (meth) acrylate, an amino group-containing polyvinyl alcohol, a polymethylene polyphenylene polyisocyanate, an oxazoline group-containing poly (meth) acrylate, and a toluene diisocyanate copolymer polyurethane. The laminate is characterized by containing at least one of the diphenylmethane diisocyanate copolymer polyurethane.
In the present specification, polymethylene polyphenylene polyisocyanate is referred to as "polymeric MDI", toluene diisocyanate is referred to as "TDI", and diphenylmethane diisocyanate is referred to as "MDI".
In addition, in this specification, "(meth) acrylate" means acrylate or methacrylate.

According to the present invention, it is possible to provide a laminate that is firmly adhered and has resistance to sebum and alcohol.

Schematic cross-sectional view showing the first embodiment of the present invention. Schematic cross-sectional view showing a second embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a third embodiment of the present invention. The schematic perspective view which shows the 4th Embodiment of this invention. FIG. 6 is a schematic cross-sectional view cut along the line AA in FIG.

The laminate according to the present invention has an adherend, a primer layer and an adhesive layer. The primer layer is laminated on the adherend, and the pressure-sensitive adhesive layer is laminated on the surface of the primer layer opposite to the adherend. The pressure-sensitive adhesive layer contains a (meth) acrylate copolymer containing 30% by weight or more and 70% by weight or less of a constituent unit derived from a fluorine-containing (meth) acrylate. The primer layer contains at least one of amino group-containing poly (meth) acrylate, amino group-containing polyvinyl alcohol, polypeptide MDI, oxazoline group-containing poly (meth) acrylate, TDI copolymer polyurethane, and MDI copolymer polyurethane. do. By having the above structure, the interfacial adhesive strength between the layers of the adherend, the primer layer and the pressure-sensitive adhesive layer is excellent, and in particular, the interfacial adhesive strength is excellent even when an adherend generally called a difficult-adhesive body is used. .. Further, the primer layer and the pressure-sensitive adhesive layer are excellent in resistance to sebum and alcohol. As a result, the laminate according to the present invention can be firmly adhered and exhibit excellent resistance to sebum and alcohol.
Hereinafter, each embodiment will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a schematic cross-sectional view showing the first embodiment of the present invention.
As shown in FIG. 1, the laminate 11 according to the first embodiment has a first adherend 4a, a first primer layer 3a, and a first pressure-sensitive adhesive layer 2a. The first primer layer 3a is laminated on the first adherend 4a, and the first pressure-sensitive adhesive layer 2a is laminated on the surface of the first primer layer 3a opposite to the first adherend 4a. There is.

[Adhesive layer]
The pressure-sensitive adhesive layer constituting the laminate according to the present invention contains a (meth) acrylate copolymer having a structural unit derived from a fluorine-containing (meth) acrylate. Since the (meth) acrylate copolymer contains a structural unit derived from the fluorine-containing (meth) acrylate, the high water and oil repellency of fluorine itself and the dense packing of fluorine atoms make the above (meth). It is possible to suppress the infiltration of sebum and alcohol into the molecular chain of the acrylate copolymer. As a result, the laminate according to the present invention has excellent resistance to sebum and alcohol.

The fluorine-containing (meth) acrylate is not particularly limited, but is preferably a (meth) acrylate having a fluoroalkyl group. Examples of the (meth) acrylate having a fluoroalkyl group include 2,2,2-trifluoroethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2,2,3,3,3. -Pentafluoropropyl (meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, 3-perfluorobutyl-2-hydroxypropyl (meth) acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth) Acrylate, 3- (Perfluoro-3-methylbutyl) -2-hydroxypropyl (meth) acrylate, 1H, 1H, 3H-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 7H-dodecafluoroheptyl (meth) acrylate, 1H-1- (trifluoromethyl) trifluoroethyl (meth) acrylate, 1H, 1H, 3H-hexafluorobutyl (meth) acrylate and 1,2,2 , 2-Tetrafluoro-1- (trifluoromethyl) ethyl (meth) acrylate and the like.
Of these, 2- (perfluorohexyl) ethyl acrylate (13F) or 2,2,2-trifluoroethyl acrylate (3F) is preferable because of its high resistance to sebum and alcohol. From the viewpoint of easily adjusting the adhesive strength by lowering the glass transition point of the (meth) acrylate copolymer, acrylate is preferable.
These fluorine-containing (meth) acrylates may be used alone or in combination of two or more.

The content of the constituent unit derived from the fluorine-containing (meth) acrylate is 30% by weight or more and 70% by weight or less in 100% by weight of all the constituent units of the (meth) acrylate copolymer. When the content is at least the above lower limit, it is possible to suppress the infiltration of sebum and alcohol into the molecular chain of the (meth) acrylate copolymer. Therefore, it is considered that the swelling rate of the (meth) acrylate copolymer with respect to sebum and alcohol is lowered, and the resistance of the pressure-sensitive adhesive layer to sebum and alcohol is improved. When the content is not more than the upper limit, the adhesive layer does not become too hard, sufficient tackiness can be maintained, and sufficient adhesive strength can be exhibited.
The preferred lower limit of the content is 40% by weight, the preferred upper limit is 60% by weight, and the more preferable lower limit is 50% by weight.

The (meth) acrylate copolymer preferably further has a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 6 or more carbon atoms. Since the (meth) acrylate copolymer contains a structural unit derived from the alkyl (meth) acrylate having an alkyl group having 6 or more carbon atoms, the pressure-sensitive adhesive layer is further excellent in alcohol resistance.

The alkyl (meth) acrylate having an alkyl group having 6 or more carbon atoms is not particularly limited. For example, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, isostearyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, decyl (meth). ) Acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate and the like can be mentioned. Of these, 2-ethylhexyl (meth) acrylate or octyl (meth) acrylate is preferable from the viewpoint of enhancing the adhesive strength of the pressure-sensitive adhesive layer. These alkyl (meth) acrylates having an alkyl group having 6 or more carbon atoms may be used alone or in combination of two or more.

The content of the structural unit derived from the alkyl (meth) acrylate having an alkyl group having 6 or more carbon atoms is preferably 20% by weight in 100% by weight of all the structural units of the (meth) acrylate copolymer. The preferred upper limit is 50% by weight. When the content is at least the above lower limit value, the adhesive layer does not become too hard and can be deformed when a peeling force is applied, so that sufficient adhesive force can be exhibited. When the content is not more than the above upper limit value, the pressure-sensitive adhesive layer does not become too soft, sufficient cohesive force can be maintained, and sufficient adhesive force can be exhibited. In addition, resistance to alcohol can be further enhanced without impairing resistance to sebum. A more preferable upper limit of the content is 45% by weight.

The (meth) acrylate copolymer preferably further contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms. When the (meth) acrylate copolymer contains a structural unit derived from the alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms, the entanglement between the polymers is increased and the pressure-sensitive adhesive layer is increased. Adhesion and cohesiveness are improved. This makes it difficult for the pressure-sensitive adhesive layer to peel off, and it is possible to suppress the infiltration of sebum and alcohol into the adhesive interface. As a result, the resistance of the laminate to sebum and alcohol is further improved.
Further, the (meth) acrylate copolymer may further enhance the polarity of the pressure-sensitive adhesive layer by containing a structural unit derived from the alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms. can. As a result, the resistance of the laminated body to sebum can be further enhanced.

The alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate and the like can be mentioned. Of these, ethyl acrylate or methyl acrylate is preferable. By using ethyl acrylate or methyl acrylate, the pressure-sensitive adhesive layer does not become too hard, and sufficient adhesive strength can be exhibited. In addition, the resistance of the pressure-sensitive adhesive layer to sebum can be further enhanced.
As these alkyl (meth) acrylates having an alkyl group having 2 or less carbon atoms, only one kind may be used, or two or more kinds may be used in combination.

The content of the structural unit derived from the alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms is 100% by weight of all the structural units of the (meth) acrylate copolymer, and the preferable lower limit is 10% by weight. The preferred upper limit is 40% by weight. When the content is in the above range, it is possible to prevent the polarity of the (meth) acrylate copolymer from becoming too high. This makes it possible to further improve the resistance to sebum without impairing the resistance to alcohol. The more preferable lower limit of the content is 15% by weight, and the more preferable upper limit is 30% by weight.

The (meth) acrylate copolymer preferably further contains a polar functional group. By including the polar functional group in the (meth) acrylate copolymer, the cohesive force of the pressure-sensitive adhesive layer can be enhanced and the adhesive force can be enhanced.

The polar functional group has reactivity such as a cross-linking reaction, and is preferably at least one selected from the group consisting of a hydroxyl group, a carboxy group, an amino group and an epoxy group. Of these, a hydroxyl group or a carboxy group is more preferable, and a carboxy group is particularly preferable, because it can contribute to the improvement of the interfacial adhesive force with the adherend or the primer layer. When the (meth) acrylate copolymer contains a carboxy group, the carboxy group can be condensed or interact with the primer contained in the primer layer. As a result, it is possible to obtain a laminated body that is more firmly adhered.
In order to contain the polar functional group, the (meth) acrylate copolymer preferably contains a structural unit derived from the monomer having the polar functional group. Examples of the monomer having a hydroxyl group include (meth) acrylate having a hydroxyl group such as 4-hydroxybutyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.
Examples of the monomer having a carboxy group include (meth) acrylic acid and the like.
Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and the like.
The monomers having these polar functional groups may be used alone or in combination of two or more.

The content of the structural unit derived from the monomer having the polar functional group is not particularly limited, but in 100% by weight of all the structural units of the (meth) acrylate copolymer, the preferable lower limit is 0.1% by weight and the preferable upper limit is 0.1% by weight. 5% by weight. When the content is in the above range, the cohesive force of the pressure-sensitive adhesive layer can be further enhanced. In addition, it becomes easy to adjust the gel fraction and the swelling ratio of the pressure-sensitive adhesive layer.

The (meth) acrylate copolymer may further contain a structural unit derived from another monomer. Examples of such a monomer include propyl acrylate, butyl acrylate, benzyl acrylate, phenoxyethyl acrylate, vinyl acetate, acrylonitrile and the like.

The (meth) acrylate copolymer preferably has a lower limit of the weight average molecular weight of 300,000 and an upper limit of 1.5 million. When the weight average molecular weight of the (meth) acrylate copolymer is 300,000 or more, the cohesive force of the pressure-sensitive adhesive layer is improved, and the resistance to sebum and alcohol is improved. When the weight average molecular weight of the (meth) acrylate copolymer is 1.5 million or less, the interfacial adhesive strength between the pressure-sensitive adhesive layer and the adherend or primer layer is high, and the resistance of the laminate to sebum and alcohol is improved. do. The more preferable lower limit of the weight average molecular weight is 400,000, the more preferable upper limit is 1.2 million, the more preferable lower limit is 500,000, and the further preferable upper limit is 1.1 million.
The weight average molecular weight can be adjusted by the polymerization conditions (for example, the type or amount of the polymerization initiator, the polymerization temperature, the monomer concentration, etc.).

In the present specification, the weight average molecular weight (Mw) means a value measured as a polystyrene-equivalent molecular weight by a gel permeation chromatography (GPC) method. Specifically, the measurement sample is diluted 50-fold with tetrahydrofuran (THF) and measured as a polystyrene-equivalent molecular weight by the GPC method using a sample filtered through a filter. As the column used in the GPC method, for example, 2690 Separations Model (manufactured by Waters) or the like can be used.

In order to synthesize the (meth) acrylate copolymer, the monomer from which the above-mentioned structural unit is derived may be polymerized in the presence of a polymerization initiator. By polymerizing the monomer from which the structural unit is derived, a copolymer containing the structural unit can be obtained.
The polymerization method is not particularly limited, and a conventionally known method can be used. For example, solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like can be mentioned. Of these, solution polymerization is preferable because it is easy to synthesize. Emulsion polymerization is preferable, especially when the content of the structural unit derived from acrylonitrile is increased.

When solution polymerization is used as the polymerization method, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether and the like. These reaction solvents may be used alone or in combination of two or more.

The polymerization initiator is not particularly limited, and a radical polymerization initiator, an anionic polymerization initiator, a cationic polymerization initiator and the like can be used. Above all, a radical polymerization initiator can be preferably used.
Examples of the radical polymerization initiator include organic peroxides and azo compounds. Examples of the organic peroxide include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5. -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Examples thereof include isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate and t-butylperoxylaurate. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

The pressure-sensitive adhesive layer preferably contains a cross-linking agent. By containing the above-mentioned cross-linking agent, the polar functional group of the structural unit derived from the above-mentioned monomer having a polar functional group can be cross-linked to construct a cross-linked structure. This makes it easier to adjust the gel fraction and swelling ratio of the pressure-sensitive adhesive layer.

The above-mentioned cross-linking agent is not particularly limited, and examples thereof include an isocyanate-based cross-linking agent, an aziridine-based cross-linking agent, an epoxy-based cross-linking agent, and a metal chelate-type cross-linking agent. Among them, an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent is preferable, and an isocyanate-based cross-linking agent is more preferable. By using these cross-linking agents, the bonds formed after the cross-linking reaction are polarized. Therefore, the pressure-sensitive adhesive layer easily interacts with the adherend or the primer layer, and the interfacial adhesive force becomes strong.

The content of the cross-linking agent is not particularly limited, but the preferable lower limit is 0.001 part by weight and the preferable upper limit is 20 parts by weight with respect to 100 parts by weight of the (meth) acrylate copolymer. A more preferable lower limit of the content is 0.005 parts by weight, a more preferable upper limit is 10 parts by weight, a further preferable lower limit is 0.01 parts by weight, and a further preferable upper limit is 5 parts by weight.

The pressure-sensitive adhesive layer preferably contains a silane coupling agent. By containing the silane coupling agent, the adhesive strength of the pressure-sensitive adhesive layer can be enhanced.

The silane coupling agent is not particularly limited. For example, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-Glysidoxypropylmethyldiethoxysilane, 3-Glysidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxy Silane, 3-aminopropyltrimethylmethoxysilane, N- (2-aminoethyl) 3-aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, Examples thereof include 3-mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane. Of these, 3-glycidoxypropyltrimethoxysilane is preferable.

Regarding the content of the silane coupling agent, the preferable lower limit is 0.1 part by weight and the preferable upper limit is 5 parts by weight with respect to 100 parts by weight of the (meth) acrylate copolymer. When the content is at least the above lower limit value, the interfacial adhesive strength of the pressure-sensitive adhesive layer is further improved, and the resistance of the laminated body to sebum and alcohol is improved. When the content is not more than the upper limit, it is possible to suppress the adhesive residue on the adherend or the primer layer when the pressure-sensitive adhesive layer is peeled off. As a result, the reworkability at the time of manufacturing the laminate is improved.
A more preferable lower limit of the content is 0.5 parts by weight, a more preferable upper limit is 4 parts by weight, a further preferable lower limit is 1 part by weight, and a further preferable upper limit is 3 parts by weight.

The pressure-sensitive adhesive layer may contain an emulsifier, a softener, a filler, an additive such as a pigment or a dye, a pressure-sensitive adhesive such as a rosin-based resin or a terpene-based resin, and other resins, if necessary. ..

The gel fraction of the pressure-sensitive adhesive layer is preferably 5% by weight or more and 70% by weight or less. When the gel fraction is at least the above lower limit value, the cohesive force of the pressure-sensitive adhesive layer is improved. When the gel fraction is equal to or less than the upper limit, the adhesive strength of the pressure-sensitive adhesive layer is improved. Further, since the adhesive layer does not become too hard and can be deformed when a peeling force is applied, sufficient adhesive force can be exhibited. When the gel fraction is within the above range, the laminate is adhered more firmly, and the resistance to sebum and alcohol is further improved.
The more preferable lower limit of the gel fraction is 10% by weight, the more preferable upper limit is 55% by weight, the further preferable lower limit is 25% by weight, the further preferable upper limit is 40% by weight, and the particularly preferable lower limit is 30% by weight. ..
The gel fraction can be adjusted, for example, by changing the content of the cross-linking agent, the amount of the monomer having a reactive functional group such as the cross-linking reaction in the (meth) acrylate copolymer, and the like.
The "gel fraction" in the present specification refers to the weight of the adhesive tape having the pressure-sensitive adhesive layer before being immersed in ethyl acetate as shown in the following formula (1), after being immersed in ethyl acetate and dried. It is a value expressed as a percentage of the weight ratio of the adhesive tape having the said adhesive layer.
Gel fraction (% by weight) = 100 x (W ₂ -W ₀ ) / (W ₁ -W ₀ ) (1)
(W ₀ : weight of base material, W ₁ : weight of adhesive tape having the above-mentioned pressure-sensitive adhesive layer before dipping in ethyl acetate, W ₂ : weight of the pressure-sensitive adhesive tape having the above-mentioned pressure-sensitive adhesive layer after dipping in ethyl acetate and drying)

The pressure-sensitive adhesive layer has a swelling rate (also referred to as "alcohol swelling rate") of 100% by weight after being immersed in a mixed solution of 75% by weight of ethanol and 25% by weight of water under the conditions of 60 ° C. and 90% humidity. As mentioned above, it is preferably 150% by weight or less. When the alcohol swelling rate is 100% by weight or more, it means that the pressure-sensitive adhesive component does not elute into the mixed solution, and the alcohol resistance of the pressure-sensitive adhesive layer is improved. When the alcohol swelling rate is 150% by weight or less, the alcohol resistance of the pressure-sensitive adhesive layer is improved. A more preferable upper limit of the alcohol swelling rate is 140% by weight, and a further preferable upper limit is 130% by weight.
The "alcohol swelling rate" in the present specification is a value represented by the following formula (2). That is, the "alcohol swelling rate" is 75% by weight of ethanol and 25% by weight of water with respect to the weight of the adhesive tape having the adhesive layer before being immersed in the mixed solution of 75% by weight of ethanol and 25% by weight of water. It is a value expressed as a percentage of the weight ratio of the pressure-sensitive adhesive tape having the above-mentioned pressure-sensitive adhesive layer after being immersed in the mixed solution of the above and dried. If there is elution of the pressure-sensitive adhesive component into a mixture of ethanol and water, the alcohol swelling rate is less than 100% by weight.
Alcohol swelling rate (% by weight) = 100 x (W ₅ -W ₃ ) / (W ₄ -W ₃ ) (2)
(W ₃ : Weight of base material, W ₄ : Weight of adhesive tape having the above-mentioned adhesive layer before immersion in a mixed solution of 75% by weight of ethanol and 25% by weight of water, W ₅ : 75% by weight of ethanol and 25% by weight of water The weight of the adhesive tape having the above-mentioned adhesive layer after immersion in a mixed solution with% and drying)

The pressure-sensitive adhesive layer may have a swelling rate (also referred to as "oleic acid swelling rate") of 100% by weight or more and 130% by weight or less after being immersed in oleic acid at 60 ° C. and a humidity of 90% for 24 hours. preferable. A more preferable upper limit of the oleic acid swelling rate is 120% by weight, and a further preferable upper limit is 115% by weight.
The "oleic acid swelling rate" in the present specification is a value represented by the following formula (3). That is, the "oleic acid swelling rate" is the weight of the adhesive tape having the pressure-sensitive adhesive layer after being immersed in oleic acid and dried with respect to the weight of the pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer before being immersed in oleic acid. It is a value expressed as a percentage of. In the presence of elution of the adhesive component into oleic acid, the oleic acid swelling rate is less than 100% by weight.
Oleic acid swelling rate (% by weight) = 100 × (W ₈ -W ₆ ) / (W ₇ -W ₆ ) (3)
(W ₆ : Weight of the base material, W ₇ : Weight of the adhesive tape having the adhesive layer before oleic acid immersion, W ₈ : Weight of the adhesive tape having the adhesive layer after oleic acid immersion and drying)

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but a preferable lower limit is 5 μm and a preferable upper limit is 100 μm. When the thickness of the pressure-sensitive adhesive layer is 5 μm or more, the adhesive strength of the pressure-sensitive adhesive layer is improved. When the thickness of the pressure-sensitive adhesive layer is 100 μm or less, the processability of the pressure-sensitive adhesive layer is improved.

[Primer layer]
The primer layer constituting the laminate according to the present invention is an amino group-containing poly (meth) acrylate, an amino group-containing polyvinyl alcohol, a polymeric MDI, an oxazoline group-containing poly (meth) acrylate, a TDI copolymer polyurethane and an MDI copolymer. It contains at least one of polyurethanes (also referred to herein as a primer).
Among various pressure-sensitive adhesives and primers, by combining the above-mentioned pressure-sensitive adhesive layer and the above-mentioned primer layer containing the above-mentioned primer, the laminate according to the present invention is firmly adhered and has excellent resistance to sebum and alcohol. ..
Of these, amino group-containing poly (meth) acrylates or amino group-containing polyvinyl alcohols are preferable, and amino group-containing poly (meth) acrylates are particularly preferable. By using these primers, it is possible to obtain a laminate that is more firmly adhered and has excellent resistance to sebum and alcohol.

The primer contained in the primer layer has at least one functional group among an amino group, an oxazoline group, an isocyanate group, a urea bond and a urethane bond. By having these functional groups, the primer contained in the primer layer and the functional group contained in the (meth) acrylate copolymer contained in the pressure-sensitive adhesive layer can be condensed or interact with each other. Therefore, it is considered that the interfacial adhesive force between the primer layer and the pressure-sensitive adhesive layer is further improved. Further, by having these functional groups, the primer layer is also excellent in interfacial adhesive force with the adherend, and in particular, even when an adherend generally called a difficult adherent is used, the interface is formed. Excellent adhesive strength. As a result, it is possible to obtain a laminate that is firmly adhered and has resistance to sebum and alcohol.

The primer contained in the primer layer is preferably a polymer compound.
The primer contained in the primer layer is preferably linear. Since the primer contained in the primer layer is linear, the entanglement with the (meth) acrylate copolymer contained in the pressure-sensitive adhesive layer is increased. Therefore, it is considered that the interfacial adhesive force between the primer layer and the pressure-sensitive adhesive layer is further improved. As a result, a more firmly bonded laminate can be obtained.

Among the primers contained in the primer layer, commercially available primers include Polyment NK350 (amino group-containing poly (meth) acrylate primer, manufactured by Nippon Shokubai Co., Ltd.) and Millionate MR-200 (polymeric MDI primer, manufactured by Tosoh Co., Ltd.). And so on. In addition, Epocross WS-300, Epocross WS-500 (all of which are oxazoline group-containing poly (meth) acrylate primers, manufactured by Nippon Catalyst Co., Ltd.), Vernock DM-653 and Vernock DM-678 (TDI copolymer polyurethane primer and MDI, respectively). Polymer polyurethane primer, both manufactured by DIC) and the like.
The primers used for these primer layers may be used alone or in combination of two or more.

The molecular weight of the primer contained in the primer layer is preferably 10,000 or more. When the molecular weight is at least the lower limit, the entanglement between the (meth) acrylate copolymer contained in the pressure-sensitive adhesive layer and the primer contained in the primer layer increases. As a result, the interfacial adhesive force between the primer layer and the pressure-sensitive adhesive layer is further improved.
The lower limit of the molecular weight is more preferably 20,000, still more preferably 50,000.
The upper limit of the molecular weight is more preferably 1 million, still more preferably 500,000.
When the molecular weight is within the above range, a more firmly bonded laminate can be obtained.

The primer layer may contain other components. Examples of such components include water-soluble resins, tackifiers, and conventionally known additives.

The thickness of the primer layer is not particularly limited. The preferred lower limit of the thickness is 1 nm, and the preferred upper limit is 5 μm.

[Subject]
The laminate according to the present invention has an adherend. The adherend is not particularly limited, and a metal, an inorganic material, an organic resin, or the like can be used.
Examples of the metal include stainless steel (SUS) and the like.
Examples of the inorganic material include glass and the like.
Examples of the organic resin include polyolefin resins, polyethylene resins, polycarbonate resins, silicone resins, fluororesins, polyarylamide resins and the like.

The adherend is preferably made of an organic resin because the laminate is more firmly adhered. Among them, a polyarylamide resin can be preferably used.
The laminate according to the present invention can be firmly adhered and exhibit excellent resistance to sebum and alcohol even when an adherend generally referred to as a difficult adherent is used.

(Second embodiment)
FIG. 2 is a schematic cross-sectional view showing a second embodiment of the present invention.
As shown in FIG. 2, in the laminated body 12 according to the second embodiment, the first primer layer 3a is laminated on the first adherend 4a, and the first adherence of the first primer layer 3a is performed. The first pressure-sensitive adhesive layer 2a is laminated on the surface opposite to the body 4a. Further, the second primer layer 3b and the second adherend 4b are laminated in this order on the surface of the first pressure-sensitive adhesive layer 2a opposite to the first primer layer 3a.
In the laminate according to the second embodiment, it is possible to provide a laminate in which the first adherend and the second adherend are firmly adhered to each other and have resistance to sebum and alcohol. can.

The second adherend may be made of the same material as the first adherend, or may be made of a different material.

As shown in FIG. 2, when the laminate according to the present invention has a second adherend, a second primer layer is provided between the second adherend and the first pressure-sensitive adhesive layer. Is preferable. By having the second primer layer, the laminate is adhered more firmly, and the resistance to sebum and alcohol is further improved.

The second primer layer may have the same composition as the first primer layer, or may have a different composition. The primer contained in the second primer layer is not particularly limited, and known primers can be used. The second primer layer, like the first primer layer, contains amino group-containing poly (meth) acrylate, amino group-containing polyvinyl alcohol, polypeptide MDI, oxazoline group-containing poly (meth) acrylate, TDI copolymer polyurethane, and MDI. It is preferable to contain at least one of the polymer polyurethanes. Of these, amino group-containing poly (meth) acrylates are preferable. By containing the above-mentioned primer, the laminate can be adhered more firmly and the resistance to sebum and alcohol can be enhanced.
Only one kind of these primers may be used, or two or more kinds thereof may be used in combination.

(Third embodiment)
FIG. 3 is a schematic cross-sectional view showing a third embodiment of the present invention.
As shown in FIG. 3, in the laminated body 13 according to the third embodiment, the first primer layer 3a is laminated on the first adherend 4a, and the first adherence of the first primer layer 3a is performed. The first pressure-sensitive adhesive layer 2a is laminated on the surface opposite to the body 4a. Further, the base material 5 is laminated on the surface of the first pressure-sensitive adhesive layer 2a opposite to the first primer layer 3a, and the second pressure-sensitive adhesive is placed on the surface of the base material 5 opposite to the first pressure-sensitive adhesive layer 2a. Layers 2b are laminated. The second primer layer 3b and the second adherend 4b are laminated in this order on the surface of the second pressure-sensitive adhesive layer 2b opposite to the base material 5.
Also in the laminate according to the third embodiment, it is possible to provide a laminate in which the first adherend and the second adherend are firmly adhered to each other and have resistance to sebum and alcohol. can.

As shown in FIG. 3, the laminate according to the present invention may have another layer such as a base material in addition to the adherend, the primer layer and the pressure-sensitive adhesive layer. For example, by having a base material, it is possible to further impart impact resistance and the like to the laminated body.

The base material is not particularly limited, and for example, a polyolefin-based resin film such as a polyethylene film or a polypropylene film, a polyester-based resin film such as a PET film, or the like can be used. Further, examples thereof include an ethylene-vinyl acetate copolymer film, a polyvinyl chloride resin film, a polyurethane resin film, a polyethylene foam sheet, a polyolefin foam sheet such as a polypropylene foam sheet, and a polyurethane foam sheet. Of these, PET film is preferable. Further, from the viewpoint of impact resistance, a polyolefin foam sheet is preferable. Further, as the base material, a base material printed in black to prevent light transmission, a base material printed in white to improve light reflectivity, a base material vapor-deposited with metal, or the like can also be used.

The thickness of the base material is not particularly limited, but a preferable lower limit is 50 μm and a preferable upper limit is 400 μm. When the thickness of the base material is 50 μm or more, the impact resistance of the laminated body is further improved. When the thickness of the base material is 400 μm or less, it is suitable for a component fixing portion of an electronic device.

The second pressure-sensitive adhesive layer may have the same composition as the first pressure-sensitive adhesive layer, or may have a different composition. The second pressure-sensitive adhesive layer is not particularly limited and can be formed from a known pressure-sensitive adhesive. Like the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer preferably contains a (meth) acrylate copolymer containing a structural unit derived from the above-mentioned fluorine-containing (meth) acrylate. When the second pressure-sensitive adhesive layer contains the above (meth) acrylate copolymer, the resistance of the laminate to sebum and alcohol can be further improved.

(Fourth Embodiment)
FIG. 4 is a schematic perspective view showing a fourth embodiment of the present invention. FIG. 5 is a schematic cross-sectional view cut along the line AA in FIG.
As shown in FIGS. 4 and 5, in the laminated body 14 according to the fourth embodiment, the first primer layer 3a is laminated on the first adherend 4a, and the first primer layer 3a is the first. The first pressure-sensitive adhesive layer 2a is laminated on the surface opposite to the adherend 4a. Further, the second adherend 4b is laminated on the surface of the first pressure-sensitive adhesive layer 2a opposite to the first primer layer 3a.
In the laminated body according to the fourth embodiment, the first primer layer and the first pressure-sensitive adhesive layer are laminated on a part of the first adherend and the second adherend.
Also in the laminate according to the fourth embodiment, it is possible to provide a laminate in which the first adherend and the second adherend are firmly adhered to each other and have resistance to sebum and alcohol. can.

The laminate according to the present invention is strongly adhered and has excellent resistance to sebum and alcohol, and can maintain the adhesive strength even when sebum or an alcoholic beverage is adhered. Therefore, as shown in FIGS. 4 and 5, even if the width of the primer layer and the pressure-sensitive adhesive layer in the laminate according to the present invention is narrow, it can be preferably used. For example, even when the width of the primer layer and the pressure-sensitive adhesive layer is 5 mm or less, it can be preferably used.
The shape of the laminated body according to the present invention is not particularly limited and may be a rectangle or the like. Since the laminated body according to the present invention is suitable for the fixed portion of the touch panel portion or the display panel portion, the shape in a plan view is preferably a frame shape.

(Manufacturing method of laminated body)
The method for producing the laminate according to the present invention is not particularly limited. For example, the primer is applied onto the adherend and dried to form a primer layer, and then a pressure-sensitive adhesive is applied and dried to form a pressure-sensitive adhesive layer so as to be in contact with the primer layer. May be manufactured. Further, even if the laminate is manufactured by applying the primer to the adherend and drying it to form a primer layer, and then attaching an adhesive tape having the adhesive layer so as to be in contact with the primer layer. good. Above all, from the viewpoint of ease of production, it is preferable to apply the primer to the adherend and dry it to form a primer layer, and then attach an adhesive tape having the pressure-sensitive adhesive layer so as to be in contact with the primer layer.

The adhesive tape having the adhesive layer can be produced by the following method.
First, a solvent is added to the above (meth) acrylate copolymer and, if necessary, an additive such as a cross-linking agent or a silane coupling agent to prepare a solution of the pressure-sensitive adhesive composition a. The solution of the pressure-sensitive adhesive composition a is applied to the surface of the base material, and the solvent in the solution is completely dried and removed to form the pressure-sensitive adhesive layer a. Next, the release film is superposed on the formed pressure-sensitive adhesive layer a so that the release-treated surface faces the pressure-sensitive adhesive layer a.
Next, a release film different from the release film is prepared, a solution of the pressure-sensitive adhesive composition b is applied to the release-treated surface of the release film, and the solvent in the solution is completely dried and removed. , A laminated film having an adhesive layer b formed on the surface of the release film is produced. The obtained laminated film is laminated on the back surface of the base material on which the pressure-sensitive adhesive layer a is formed so that the pressure-sensitive adhesive layer b faces the back surface of the base material to prepare a laminated body. Then, by pressurizing the laminate with a rubber roller or the like, it is possible to obtain an adhesive tape having adhesive layers on both sides of the base material and having the surface of the adhesive layer covered with a release film.

As another manufacturing method, two sets of laminated films are produced in the same manner, and these laminated films are laminated on both sides of the base material so that the adhesive layer of the laminated film faces the base material. A laminated body can be produced, and the laminated body can be pressed by a rubber roller or the like. This makes it possible to obtain an adhesive tape having adhesive layers on both sides of the base material and having the surface of the adhesive layer covered with a release film.

The method for producing the primer layer is not particularly limited. For example, it can be obtained by applying a solution in which the primer used for the primer layer is dissolved on the adherend by a brush or a roll and sufficiently drying the adherend. The primer used for the primer layer is preferably applied in a state of being dissolved in a solvent. As the solvent, water or an organic solvent can be used.

Since the laminate according to the present invention is firmly adhered and has excellent resistance to sebum and alcohol, it can be suitably used for a component fixing portion of a portable electronic device.
Specifically, it can be suitably used as a fixing portion between the cover panel and the touch panel module or the display panel module for protecting the surface of the portable electronic device, a fixing portion between the touch panel module and the display panel module, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Manufacturing]
(1) Production of (meth) acrylate copolymer (Synthesis Example 1)
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, as a polymerization initiator, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold was put into a reaction vessel. Subsequently, 48 parts by weight of 2- (perfluorohexyl) ethyl acrylate (13F), 34 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of methyl acrylate (MA), and 3 parts by weight of acrylic acid (AAc) were added for 2 hours. It was added dropwise. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold as a polymerization initiator was put into the reaction vessel again. The polymerization reaction was carried out for 4 hours to obtain a solution containing a fluorine-containing (meth) acrylate copolymer.

(Synthesis Example 2)
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, as a polymerization initiator, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold was put into a reaction vessel. Subsequently, 30 parts by weight of 2- (perfluorohexyl) ethyl acrylate (13F), 47 parts by weight of 2-ethylhexyl acrylate (2EHA), 20 parts by weight of methyl acrylate (MA), and 3 parts by weight of acrylic acid (AAc) were added for 2 hours. It was added dropwise. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold as a polymerization initiator was put into the reaction vessel again. The polymerization reaction was carried out for 4 hours to obtain a solution containing a fluorine-containing (meth) acrylate copolymer.

(Synthesis Example 3)
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, as a polymerization initiator, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold was put into a reaction vessel. Subsequently, 70 parts by weight of 2- (perfluorohexyl) ethyl acrylate (13F), 19 parts by weight of 2-ethylhexyl acrylate (2EHA), 8 parts by weight of methyl acrylate (MA), and 3 parts by weight of acrylic acid (AAc) were added for 2 hours. It was added dropwise. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold as a polymerization initiator was put into the reaction vessel again. The polymerization reaction was carried out for 4 hours to obtain a solution containing a fluorine-containing (meth) acrylate copolymer.

(Synthesis Example 4)
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, as a polymerization initiator, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold was put into a reaction vessel. Subsequently, 97 parts by weight of 2-ethylhexyl acrylate (2EHA) and 3 parts by weight of acrylic acid (AAc) were added dropwise over 2 hours. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile with ethyl acetate 10-fold as a polymerization initiator was put into the reaction vessel again. The polymerization reaction was carried out for 4 hours to obtain a (meth) acrylate copolymer-containing solution.

(2) Production of laminated body (Example 1)
An amino group-containing poly (meth) acrylate primer (Polyment NK350, manufactured by Nippon Shokubai Co., Ltd.) was applied to a stainless steel plate using a brush and dried to form a primer layer.
In the obtained fluorine-containing (meth) acrylate copolymer-containing solution (Synthesis Example 1), coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) was added as a cross-linking agent to 100 parts by weight of the fluorine-containing (meth) acrylate copolymer. An adhesive solution was prepared by adding 1.5 parts by weight (solid component ratio) and 3 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent. This pressure-sensitive adhesive solution is applied onto a release-treated PET film having a thickness of 75 μm so that the thickness of the pressure-sensitive adhesive layer after drying is 35 μm, and then dried at 110 ° C. for 5 minutes to form a pressure-sensitive adhesive layer. rice field. Two of these pressure-sensitive adhesive layers were prepared, and both sides of a 50 μm-thick base material were transferred to both sides of a corona-treated PET film and cured at 40 ° C. for 48 hours to obtain a double-sided pressure-sensitive adhesive tape.
The obtained double-sided adhesive tape was cut into strips having a width of 5 mm, and the release film on one side was peeled off to expose the adhesive layer. This double-sided adhesive tape was placed on a stainless steel plate on which a primer layer was formed so that the exposed adhesive layer was opposed to the primer layer. Then, a 2 kg rubber roller was reciprocated once on the double-sided adhesive tape at a speed of 300 mm / min to bond the double-sided adhesive tape and the stainless steel plate on which the primer layer was formed. Then, it was allowed to stand at 23 ° C. for 24 hours to prepare a laminated body in which the adherend was a stainless steel plate.
A laminate in which the adherend was a polyarylamide resin plate was produced in the same manner, except that the adherend was changed to a polyarylamide resin plate.

(Examples 2 , 8 to 9, reference examples 3 to 7, comparative examples 1 to 7)
The type of the (meth) acrylate copolymer used for the pressure-sensitive adhesive layer and the type of the primer used for the primer layer were adhered to each other in the same manner as in Example 1 except that they were changed as shown in Table 1 or 2. A laminate whose body is a stainless steel plate and a laminate whose adherend is a polyarylamide resin plate were prepared. The following primers were used as the primers in Table 1 or Table 2.
Amino group-containing polyvinyl alcohol primer: Weight average molecular weight 60,000, amino group content 2.5 mmol / g
Polymeric MDI Primer: Millionate MR-200 (manufactured by Tosoh)
Oxazoline group-containing (meth) acrylate primer 1: Epocross WS-300 (manufactured by Nippon Shokubai Co., Ltd., oxazoline group content 4.5 mmol / g)
Oxazoline group-containing (meth) acrylate primer 2: Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd., oxazoline group content 7.7 mmol / g)
TDI Copolymer Polyurethane Primer: Burnock DM-653 (manufactured by DIC Corporation)
MDI Copolymer Polyurethane Primer: Burnock DM-678 (manufactured by DIC Corporation)
Amino group-containing polyethyleneimine 1: Epomin SP-200 (manufactured by Junsei Chemical Co., Ltd.)
Amino group-containing polyethyleneimine 2: Epomin P-1000 (manufactured by Junsei Chemical Co., Ltd.)
Amide group-containing methoxymethylated polyamide primer 1: Fine resin EM-125 (manufactured by Lead City)
Amide group-containing methoxymethylated polyamide primer 2: Fine resin EM-325 (manufactured by Lead City)
Polyester primer: Elitel UE-3520 (manufactured by Unitika Ltd.)

〔evaluation〕
(1) 180 ° peeling adhesive strength (chemical immersion test)
The same operation was repeated in each Example , Reference Example, and Comparative Example to prepare three laminated bodies each in which the adherend was a stainless steel plate, which was used as a test sample.
Using one of the three test samples prepared, a tensile test was conducted in the 180 ° direction at a peeling speed of 300 mm / min according to JIS Z0237, and the test sample was peeled off by 180 ° and had adhesive strength (N / mm) (chemicals). Before immersion) was measured.
The second test sample was immersed in a bath of oleic acid at 60 ° C. and 90% humidity for 72 hours. After taking it out, it was washed with water and allowed to stand for 24 hours. Then, the 180 ° peeling adhesive force (N / mm) (after oleic acid immersion) was measured in the same manner as the 180 ° peeling adhesive force (N / mm) (before soaking in the chemical). The 180 ° peeling adhesive strength was evaluated according to the following criteria.
◯: Adhesive strength after immersion 0.3 N / mm or more Δ: Adhesive strength after immersion 0.1 N / mm or more, less than 0.3 N / mm ×: Adhesive strength after immersion less than 0.1 N / mm

The third test sample was immersed in a bath of a mixed solution (alcohol) of 75% by weight of IPA and 25% by weight of water at 60 ° C. and 90% humidity for 72 hours. After taking it out, the adhering liquid was lightly wiped off and allowed to stand for 24 hours. Then, the 180 ° peeling adhesive force (N / mm) (after IPA / aqueous solution immersion) was measured in the same manner as the 180 ° peeling adhesive force (N / mm) (before immersion in the chemical). The 180 ° peeling adhesive strength was evaluated according to the following criteria.
◯: Adhesive strength after immersion 0.5 N / mm or more Δ: Adhesive strength after immersion 0.3 N / mm or more, less than 0.5 N / mm ×: Adhesive strength after immersion less than 0.3 N / mm

(2) 180 ° peeling adhesive strength (normal test)
Using a laminate whose adherend is a polyarylamide resin plate, a tensile test was conducted in the 180 ° direction at a peeling speed of 300 mm / min according to JIS Z0237, and 180 ° peeling adhesive strength (N / mm) ( Normal test) was measured. The 180 ° peeling adhesive strength was evaluated according to the following criteria.
⊚: Adhesive strength 1.5 N / mm or more 〇: Adhesive strength 1.0 N / mm or more, less than 1.5 N / mm Δ: Adhesive strength 0.7 N / mm or more, less than 1.0 N / mm ×: Adhesive strength 0. Less than 7N / mm

According to the present invention, it is possible to provide a laminate that is firmly adhered and has resistance to sebum and alcohol.

11, 12, 13, 14 ... Laminated body 2a ... First pressure-sensitive adhesive layer 2b ... Second pressure-sensitive adhesive layer 3a ... First primer layer 3b ... Second primer layer 4a ... First adherend 4b ... Second adherend 5 ... Base material

Claims (7)

The adherend, the primer layer and the pressure-sensitive adhesive layer are laminated in this order, and the pressure-sensitive adhesive layer contains 30% by weight or more and 70% by weight or less of a structural unit derived from a fluorine-containing (meth) acrylate (meth) acrylate. A laminate comprising a copolymer, wherein the primer layer contains an amino group-containing poly (meth) acrylate or an amino group-containing polyvinyl alcohol . The laminate according to claim 1, wherein the (meth) acrylate copolymer further has a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 6 or more carbon atoms. The laminate according to claim 2, wherein the (meth) acrylate copolymer further has a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 2 or less carbon atoms. The laminate according to any one of claims 1 to 3, wherein the (meth) acrylate copolymer has a weight average molecular weight of 1.2 million or less. The laminate according to any one of claims 1 to 4 , wherein the (meth) acrylate copolymer contains a carboxy group. The laminate according to any one of claims 1 to 5 , wherein the adherend is made of an organic resin. The laminate according to any one of claims 1 to 6 , which has a second adherend on the surface of the pressure-sensitive adhesive layer opposite to the primer layer.

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