JP2017035855A - Manufacturing method of laminate with adhesive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel manufacturing method of a laminate with an adhesive layer having a constitution by having a hard coat layer on at least back surface of a front plate resin substrate and laminating further a transparent adhesive layer on a back surface of the hard coat layer, capable of enhancing shape stability under high temperature and high humidity environment and also capable of enhancing adhesive strength between the hard coat layer and the transparent adhesive layer.SOLUTION: A laminate with adhesive layer is manufactured by adhering a hard coat resin composition to a back surface of a front plate resin substrate, primary curing them by drying or photosetting to form a hard coat preliminary layer, adhering an adhesive resin composition to a back surface of the hard coat preliminary layer to form an adhesive preliminary layer, then irradiating a light and photosetting the hard coat preliminary layer and the adhesive preliminary layer at same time.SELECTED DRAWING: None

Description

  The present invention comprises, for example, a hard coat layer on the front and back surfaces of a resin base material (referred to as “front plate resin base material”) constituting a front plate of an image display device and the like, and a transparent adhesive is further provided on the back surface of the hard coat layer. The present invention relates to a method for producing a laminate with a pressure-sensitive adhesive layer having a configuration in which layers are laminated.

  Conventionally, glass has been mainly used as a cover material of an image display device, that is, a front plate. However, since glass is easily broken by an impact and is heavy, substitution with a resin material has been studied.

The resin material as such a glass substitute material is mainly required to have impact resistance, surface hardness, and shape stability in a high temperature and high humidity environment.
Polycarbonate resin plates have transparency and are excellent in impact resistance and heat resistance, and thus are used for soundproof partitions, carports, signboards, glazing materials, lighting fixtures, and the like. However, since the surface hardness is low, it has a drawback of being easily scratched.

  In order to improve this defect, for example, Patent Document 1 discloses a resin laminate in which a laminate obtained by coextruding a polycarbonate resin and an acrylic resin is subjected to a hard coat treatment.

  Moreover, as a method for suppressing the warpage of the polycarbonate resin plate, for example, Patent Document 2 discloses a resin laminate in which a methyl methacrylate-styrene copolymer resin (MS resin) is laminated on a polycarbonate resin.

  Similarly, as a method for suppressing the warpage of the polycarbonate resin plate, Patent Document 3 discloses a resin laminate in which the glass transition temperature difference and the water absorption difference of each layer in which polycarbonate resins are laminated are defined.

JP 2006-103169 A JP 2010-167659 A WO2014 / 061817

  As described above, when a resin substrate is used as a front plate for an image display device or the like, for example, a hard coat layer is formed on the front and back surfaces of the resin substrate, and a transparent adhesive layer is further formed on the back surface of the hard coat layer. And a member such as a polarizing plate, a touch sensor, or a liquid crystal panel is appropriately bonded through the transparent adhesive layer, and used as a surface protection panel or cover material for an image display device.

However, since the resin substrate is inferior in dimensional stability in a high-temperature and high-humidity environment compared to glass, when a resin substrate is used as a front plate for an image display device or the like, it is placed in a high-temperature and high-humidity environment However, due to dimensional changes such as warpage due to moisture absorption of the resin base material, there has been a problem that peeling occurs at the interface between the front plate resin base material and the pressure-sensitive adhesive layer.
As a method of preventing the peeling between the front plate resin base material and the pressure-sensitive adhesive layer in such a high temperature and high humidity environment, the adhesive strength between the hard coat layer and the pressure sensitive adhesive layer on the back surface of the front plate resin base material can be increased. It is valid.

  Therefore, the present invention provides a method for producing a laminate with a pressure-sensitive adhesive layer comprising a hard coat layer on at least the back surface of a front plate resin base material, and further comprising a transparent pressure-sensitive adhesive layer laminated on the back surface of the hard coat layer. The present invention is intended to provide a new production method that can improve the shape stability in a high-temperature and high-humidity environment, and can further increase the adhesive strength between the hard coat layer and the transparent adhesive layer. .

  The present invention relates to a method for producing a laminate with a pressure-sensitive adhesive layer comprising a hard coat layer on at least the back surface of a front plate resin substrate, and further comprising a transparent pressure-sensitive adhesive layer laminated on the back surface of the hard coat layer. After the hard coat resin composition is adhered to the back surface of the front plate resin base material to form a hard coat preliminary layer, the photo curable adhesive resin composition is applied to the back surface of the hard coat preliminary layer. Adhering to form a pressure-sensitive adhesive pre-layer, and then irradiating light from the back side of the pressure-sensitive adhesive pre-layer to form a hard-coat pre-layer hard coat resin composition and the pressure-sensitive adhesive pre-layer pressure-sensitive adhesive resin The manufacturing method of the laminated body with an adhesive layer characterized by photocuring simultaneously with a composition is proposed.

According to the production method proposed by the present invention, the adhesive strength between the hard coat layer and the transparent pressure-sensitive adhesive layer can be increased. This is because when the hard coat resin composition and the adhesive resin composition are simultaneously photocured, a covalent bond is generated at the interface between the hard coat layer and the transparent adhesive layer, and the hard coat layer and the transparent adhesive are formed by this covalent bond. This is presumably because the adhesive strength with the layer is increased.
In addition, according to the production method proposed by the present invention, by simultaneously photocuring the hard coat resin composition and the pressure-sensitive adhesive resin composition, the shape stability in a high temperature and high humidity environment can be improved. You can also

  Therefore, the laminate with the pressure-sensitive adhesive layer obtained by the production method proposed by the present invention can be suitably used as various substrate materials and protective materials. For example, in addition to various substrate materials and protective materials as constituent materials for portable display devices such as mobile phone terminals, smartphones, portable electronic playground equipment, portable information terminals, tablet devices, mobile personal computers, wearable terminals, liquid crystal televisions, liquid crystal monitors, It can be suitably used as various substrate materials and protective materials as constituent materials for stationary display devices such as desktop personal computers, car navigation systems, and automobile meters.

  Hereinafter, an example of an embodiment of the present invention will be described in detail.

[This manufacturing method]
A method for producing a laminate with an adhesive layer (referred to as “the laminate with the present adhesive layer”) according to an example of an embodiment of the present invention (referred to as “the present production method”) comprises: A step of forming a hard coat preliminary layer by adhering to the back surface of the resin substrate (referred to as a “hard coat preliminary layer forming step”), and a back surface of the hard coat preliminary layer obtained in the step can be photocured. A step of forming a pressure-sensitive adhesive pre-layer by adhering the pressure-sensitive adhesive resin composition (referred to as “pressure-sensitive adhesive pre-layer forming step”), and irradiating light from the back side of the pressure-sensitive adhesive pre-layer formed in the step And a step of simultaneously photocuring the hard coat resin composition of the hard coat preliminary layer and the pressure sensitive adhesive resin composition of the adhesive preliminary layer (referred to as “two-layer simultaneous curing step”). .

  If this production method includes the hard coat preliminary layer forming step, the pressure sensitive adhesive preliminary layer forming step, and the two-layer simultaneous curing step described above, other steps and other treatments can be added as appropriate.

  Hereinafter, after describing the front plate resin base material used in this production method, the hard coat preliminary layer forming step, the pressure sensitive adhesive preliminary layer forming step, and the two-layer simultaneous curing step will be sequentially described.

<Front plate resin substrate>
The front plate resin substrate used in the present production method is not particularly limited in composition and configuration as long as it can be used as a substrate of a front plate of an image display device or the like, that is, a substrate constituting the front plate.
The front plate may appropriately include an arbitrary layer on the surface side of the substrate.

(Laminated body with acrylic resin layer and polycarbonate resin layer)
As an example of the front plate resin substrate, an acrylic resin layer (also referred to as “A layer”) containing an acrylic resin as a main component resin and a polycarbonate resin layer (“B” containing a polycarbonate resin as a main component resin) And a laminated body provided with “a layer”. For example, the front board of the structure formed by forming an acrylic resin layer (A layer) in the single side | surface side or both surface side of a polycarbonate-type resin layer (B layer) can be mentioned.

  Here, the “main component resin” means a resin that forms the main component of the resin composition forming each layer. The specific content of the main component resin is not specified, but as a guideline, it is 50% by mass or more of the resin contained in the resin composition forming each layer, particularly 80% by mass or more, and more than 90% by mass of the resin. (Including 100% by mass). In addition, when 2 or more types of main component resin is used, those total amounts should just correspond to the said content. The same applies to the main component resins that appear later.

(Acrylic resin layer (A layer))
As said acrylic resin layer (A layer), the layer which contains acrylic resin (a1) as a main component resin, or acrylic resin (a1), an aromatic vinyl monomer unit, (meth) acrylic A layer containing, as a main component resin, a copolymer (a2) having an acid ester monomer unit and an unsaturated dicarboxylic anhydride monomer unit can be exemplified.

The acrylic resin (a1) is a (co) polymer obtained by polymerizing a (meth) acrylic acid ester monomer unit as a main component and a derivative thereof.
Here, the “main component” means a monomer having the highest ratio among the monomer units constituting the (co) polymer and derivatives thereof.
The term “(meth) acrylic acid ester monomer unit” is intended to include an acrylic acid ester monomer unit or a methacrylic acid ester monomer unit.

  The copolymer (a2) is a copolymer having an aromatic vinyl monomer unit, a (meth) acrylic acid ester monomer unit, and an unsaturated dicarboxylic acid anhydride monomer unit.

  When the copolymer (a2) is mixed in the acrylic resin layer, the mixing mass ratio of the acrylic resin (a1) and the copolymer (a2) is (a1) / (a2) = 80/20. It is preferably ~ 20/80. If the mixing ratio of the acrylic resin (a1) and the copolymer (a2) is within the above range, the interlayer adhesion with the polycarbonate resin layer is excellent, and the surface hardness and transparency that are the characteristics of the acrylic resin are maintained. However, it is preferable because improvement in heat resistance and water absorption are suppressed.

  The acrylic resin layer (A layer) can appropriately contain various additives and other resins as long as the effects of the present invention are not impaired. Here, examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, a lubricant, a flame retardant, and a colorant. Examples of the other resin include methyl methacrylate-maleic anhydride copolymer.

(Polycarbonate resin layer (B layer))
On the other hand, the polycarbonate-based resin layer (B layer) is a layer containing the polycarbonate-based resin (b1) alone as a main component resin, and various modifiers (b2) described later are mixed with the polycarbonate-based resin (b1). And a layer contained as a main component resin.

Examples of the polycarbonate resin (b1) include aromatic polycarbonate resins and aliphatic polycarbonate resins. The polycarbonate resin (b1) may be a homopolymer or a copolymer with another copolymerizable monomer.
Further, the structure of the polycarbonate resin (b1) may be a branched structure, a linear structure, or a mixture of a branched structure and a linear structure.
The polycarbonate resin (b1) may be obtained by any known production method such as a phosgene method, a transesterification method, or a pyridine method.

  Examples of the modifier (b2) include acrylic copolymers composed of 5 to 80% by mass of aromatic (meth) acrylate monomer units and 95 to 20% by mass of methyl methacrylate monomer units. .

When the modifier (b2) is mixed in the polycarbonate resin layer (B layer), the mixing mass ratio of the polycarbonate resin (b1) and the acrylic resin (b2) is not particularly limited. It is preferable that b1) / (b2) = 99 to 65/1 to 35. It is preferable if the mixing ratio of the two is within the above range because the polycarbonate-based resin layer obtained is excellent in moldability, surface hardness improvement effect and appearance.
From this viewpoint, it is more preferable that (b1) / (b2) = 95/5 to 70/30.

The polycarbonate-based resin layer (B layer) can be blended with the above-described various additives and other resins as long as the effects of the present invention are not impaired.
Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, a lubricant, a flame retardant, a colorant, and a hydrolysis inhibitor.

(Laminated structure of layer A and layer B)
As the layer structure of the front plate resin base material provided with the acrylic resin layer (A layer) and the polycarbonate resin layer (B layer), (A) / (B), (A) / (B) / (A ) And the like. However, it is not limited to this layer structure. Here, when two or more of the same classification layers are included in the layer structure, the layers may have the same composition or different compositions.

<Hard coat preliminary layer forming step>
In this step, the hard coat resin layer may be formed by attaching the hard coat resin composition to the back surface of the front plate resin base material and drying it as necessary. That is, in this step, a hard coat preliminary layer that remains photocurable that can be photocured, in other words, a hardcoat preliminary layer that has potential photocurability, that is, a hard coat as a precursor of the hard coat layer. A preliminary layer may be formed.

(Hard coat resin composition)
The hard coat resin composition is a resin composition capable of forming a hard coat layer, and can be primarily cured by drying, and further can be secondarily cured by photocuring. preferable.

  As an example of such a hard coat resin composition, a resin composition containing a curable resin and containing a photopolymerization initiator can be given.

Specific examples of the curable resin include, for example, acrylate compounds, urethane acrylate compounds, epoxy acrylate compounds, carboxyl group-modified epoxy acrylate compounds, polyester acrylate compounds, copolymer acrylates, alicyclic epoxy resins, glycidyl ether epoxy resins, Examples thereof include vinyl ether compounds and oxetane compounds. These curable resins can be used alone or in combination of two or more.
Examples of curable resins that impart superior surface hardness include radical polymerization curable compounds such as polyfunctional acrylate compounds, polyfunctional urethane acrylate compounds, and polyfunctional epoxy acrylate compounds, and heat such as alkoxysilanes and alkylalkoxysilanes. A polymerization-type curable compound can be mentioned, Furthermore, the organic-inorganic composite-type curable resin composition formed by making the said curable resin contain an inorganic component may be sufficient.

An organic / inorganic hybrid curable resin composition can be exemplified as a hard coat resin composition that imparts particularly excellent surface hardness. Examples of the organic / inorganic hybrid curable resin composition include those composed of a curable resin composition containing an inorganic component having a reactive functional group in the curable resin.
By having such an inorganic component having a reactive functional group, for example, this inorganic component is copolymerized and crosslinked with a radical polymerizable monomer, so that an organic binder simply contains an inorganic component. -Compared with an inorganic composite type curable resin composition, since it is hard to produce shrinkage and high surface hardness can be expressed, it is preferable. Furthermore, from the viewpoint of reducing curing shrinkage, an organic / inorganic hybrid curable resin composition containing ultraviolet-reactive colloidal silica as an inorganic component having a reactive functional group can be mentioned as a more preferable example.

Further, in order to impart particularly excellent surface hardness to the hard coat layer, it is preferable to adjust the concentration of the inorganic component contained in the hard coat layer, particularly the inorganic component having a reactive functional group.
From this viewpoint, it is preferable that the concentration of the inorganic component contained in the hard coat layer, particularly the inorganic component having a reactive functional group, is 10 to 65% by mass. If the said density | concentration is 10 mass% or more, since the effect which provides the surface hardness excellent in the hard-coat layer is acquired, it is preferable. On the other hand, if the concentration is 65% by mass or less, the hard coat layer (C layer) can be filled with an inorganic component, particularly an inorganic component having a reactive functional group, with excellent surface hardness. Can be effectively imparted.
From this viewpoint, the concentration of the inorganic component is preferably 10 to 65% by mass, more preferably 20% by mass or more and 60% by mass or less, and particularly preferably 40% by mass or more or 55% by mass or less.

  Further, from the viewpoint of enhancing the adhesiveness with the transparent pressure-sensitive adhesive layer, the main component resin of the hard coat layer is preferably the same resin as the main component resin of the pressure-sensitive adhesive sheet. For example, when the main component resin of the transparent adhesive layer is an acrylic resin, the main component resin of the hard coat layer is also preferably an acrylic resin.

The hard coat resin composition contains a photopolymerization initiator, the photopolymerization initiator absorbs ultraviolet rays, and is excited and activated to cause a polymerization reaction, and a curing reaction of the ultraviolet curable resin occurs. Is preferred.
Examples of the photopolymerization initiator include benzyl, benzophenone and derivatives thereof, thioxanthones, benzyldimethylketals, αhydroxyalkylphenones, α-hydroxyacetophenones, hydroxyketones, aminoalkylphenones, acylphosphine oxides, and the like. Can be mentioned. Among these, α-hydroxyalkylphenones are preferable because they hardly cause yellowing during curing and a transparent cured product is obtained. In addition, aminoalkylphenones are preferable because they have very high reactivity and a cured product having excellent hardness can be obtained. The said photoinitiator can be used individually by 1 type or in combination of 2 or more types.
As for the addition amount of a photoinitiator, it is preferable to add 0.1-5 mass parts with respect to 100 mass parts of curable resin.

The hard coat resin composition can contain a leveling agent as a surface conditioning component.
Examples of the leveling agent include silicone leveling agents and acrylic leveling agents. In particular, those having a reactive functional group at the terminal are preferable, and those having a reactive functional group having two or more functionalities are more preferable. preferable.
Specific examples include polyether-modified polydimethylsiloxane having an acrylic group having double bonds at both ends, and a polyester-modified polydimethylsiloxane having acrylic groups having two double bonds at the ends. be able to.
Among these, polyester-modified polydimethylsiloxane having an acrylic group that has a stable haze value and contributes to improvement of scratch resistance is particularly preferable.

  In addition to the curable resin component, the hard coat resin composition includes, for example, a lubricant such as a silicon compound, a fluorine compound, or a mixed compound thereof, an antioxidant, an ultraviolet absorber, an antistatic agent, and a silicone compound. Various additives such as flame retardants, fillers, glass fibers, impact modifiers and the like can be contained within a range that does not impair the effects of the present invention.

Among the above hard coat resin compositions, the hard coat resin composition suitable for primary curing of the hard coat resin composition by drying is more than a certain level only by the coating-drying process even before photocuring with ultraviolet rays. A so-called “after cure type” coating agent that forms a “tack-free” coating film having hardness and is cured by irradiation with ultraviolet rays thereafter to form a final use form is particularly preferable.
Here, “tack-free” refers to a state in which the curable resin composition does not adhere to the fingertip when, for example, the surface of the hard coating is lightly touched with a fingertip cleaned with ethanol or the like. It is preferable that it is tack-free in the state before UV curing, from the viewpoint that it becomes easy to prevent poor appearance of the coating film and contamination due to adhered substances between the coating film formation and the bonding process with the adhesive layer. .

  When using an “after cure type” coating agent as the back hard coat layer, the coating surface is not sticky, that is, the process of attaching, storing and transporting the protective film is easy with only the drying process. Therefore, for example, it is possible to cope with the case where the manufacturing process of the resin front plate and the sticking of the adhesive layer are carried out in another factory, and the process of forming the back hard coat layer and the process of pasting the adhesive layer are not performed. It is preferable in terms of facilitating the continuous separate process.

  When a coating agent other than the “after cure” type, that is, a coating agent that remains tacky after drying, is bonded to the adhesive layer in a drying-only process and simultaneously cured, The step of pasting the agent layer is preferably a continuous step.

The above-mentioned “after cure type” coating agent is characterized in that the base polymer has a high molecular weight in order to exhibit tack-free properties before curing, and an acrylate-based polymer having a weight average molecular weight of 10,000 to 100,000. Is preferably used as the base polymer.
Examples of such after-curing type coating agents that are commercially available include “COMPOBRID IM-357H”, “COMPOBRID IM-557H”, “COMPOBRID IM-357RP”, “COMPOBRID IM-557RP” [ The above-mentioned compound series is sold by Atomics Co.], “Unidic RC29-120”, “Unidic EKC-1054” (the above Unidic series are sold by DIC), and the like.

(Formation of hard coat preliminary layer)
The hard coat preliminary layer can be formed by adhering the hard coat resin composition to the back surface of the front plate resin substrate and drying and primary curing as necessary.

As a method for adhering the hard coat resin composition to the back surface of the front plate resin substrate, the hard coat resin composition may be applied as a paint in which the hard coat resin composition is dissolved or dispersed in an organic solvent. However, it is not limited to this method.
As a coating method at this time, a known method can be used. For example, laminating method using cover film, dip coating method, natural coating method, reverse coating method, comma coater method, roll coating method, spin coating method, wire bar method, extrusion method, curtain coating method, spray coating method, The gravure coat method etc. can be mentioned.

  In addition, various surface treatments such as corona treatment, plasma treatment and primer treatment can be performed on the surface of the front plate resin substrate for the purpose of improving the adhesion between the hard coat layer and the surface of the front plate resin substrate.

  What is necessary is just to determine the drying conditions in the case of forming a hard-coat preliminary layer by drying suitably with the kind of solvent used, quantity, and the prescription of other hard-coat layers. For example, the drying temperature can be 40 to 150 ° C., and the drying time can be 10 seconds to 5 minutes.

  In the step of forming the hard coat preliminary layer, it is sufficient that the hard coat preliminary layer can be formed while leaving photocurability that can be photocured. For example, the hard coat resin composition is formed on the back surface of the front plate resin base material. The hard coat resin composition may be primarily cured by irradiating with light and leaving the photo-curability to form a hard coat preliminary layer after being attached to the substrate and dried as necessary. .

<Adhesive preliminary layer forming step>
In this step, a pressure-sensitive adhesive resin composition is attached to the back surface of the hard coat preliminary layer obtained in the above step to form a pressure-sensitive adhesive preliminary layer.

(Adhesive resin composition)
If the adhesive resin composition used for this manufacturing method is a photocurable adhesive resin composition, the composition will not be specifically limited. However, it is preferable to use a transparent pressure-sensitive adhesive layer obtained by crosslinking a pressure-sensitive adhesive composition containing an acrylic resin as a main component resin from the viewpoints of pressure-sensitive adhesiveness, transparency and weather resistance.
The pressure-sensitive adhesive composition may be in any form such as liquid, paste, or sheet. In terms of ease of handling, a sheet-like pressure-sensitive adhesive composition is particularly preferable.

  As a suitable example of the pressure-sensitive adhesive composition, a pressure-sensitive adhesive resin composition containing an acrylic resin, a crosslinking monomer, and a crosslinking initiator, a reaction catalyst, and the like as necessary can be mentioned.

As the acrylic resin as the main component resin, an acrylate polymer (including a copolymer) is preferable.
Acrylic acid ester polymers (including copolymers) have properties such as glass transition temperature (Tg) depending on the types and composition ratios of acrylic monomers and methacrylic monomers used to polymerize them, and polymerization conditions. It is possible to adjust appropriately.
Examples of the acrylic monomer and methacrylic monomer used for polymerizing the acrylate polymer include 2-ethylhexyl acrylate, n-octyl acrylate, n-butyl acrylate, ethyl acrylate, methyl methacrylate, and the like. Vinyl acetate, hydroxyethyl acrylate, acrylic acid, glycidyl acrylate, acrylamide, acrylonitrile, methacrylonitrile, fluorine acrylate, silicone acrylate, etc., which are copolymerized with a hydrophilic group or an organic functional group, can also be used.

Among the acrylic ester polymers, (meth) acrylic acid alkyl ester copolymers are particularly preferable.
The (meth) acrylate used for forming the (meth) acrylic acid alkyl ester copolymer, that is, as the alkyl acrylate or alkyl methacrylate component, the alkyl group is n-octyl, isooctyl, 2-ethylhexyl, n-butyl, One of alkyl acrylate or alkyl methacrylate which is any one of isobutyl, methyl, ethyl and isopropyl, or a mixture of two or more selected from these is preferable.

As other components, an acrylate or methacrylate having an organic functional group such as a carboxyl group, a hydroxyl group, or a glycidyl group may be copolymerized. Specifically, a monomer component obtained by appropriately and selectively combining the alkyl (meth) acrylate component and the (meth) acrylate component having an organic functional group as a starting material is subjected to heat polymerization to form a (meth) acrylate ester copolymer. A polymer polymer can be obtained.
Among them, preferably, an alkyl acrylate such as iso-octyl acrylate, n-octyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, or a mixture of two or more selected from these, or iso-octyl acrylate, Examples thereof include those obtained by copolymerizing at least one kind of n-octyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like with acrylic acid.

Examples of crosslinking monomers (also referred to as “crosslinking agents”) include organic compounds such as polyfunctional (meth) acrylates having two or more (meth) acryloyl groups, isocyanate groups, epoxy groups, melamine groups, glycol groups, siloxane groups, and amino groups. A polyfunctional organic functional group resin having two or more functional groups, an organometallic compound having a metal complex such as zinc, aluminum, sodium, zirconium, or calcium can be used.
Examples of the above polyfunctional (meth) acrylates include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, trimethylolpropane triacrylate, and the like. be able to.

  The content of the crosslinking monomer may be adjusted in combination with other factors so as to obtain a desired holding power, but generally 0.01 to 40.0 parts by mass, preferably 100 parts by mass with respect to 100 parts by mass of the main component resin. Is preferably adjusted within a range of 0.1 to 30.0 parts by mass, particularly 0.5 to 30.0 parts by mass. However, this range may be exceeded in balance with other elements.

  When crosslinking the acrylic ester polymer, a crosslinking initiator (peroxidation initiator, photopolymerization initiator) and reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) are appropriately used. It is effective when added.

  In the case of curing by irradiation with ultraviolet rays, that is, when ultraviolet crosslinking (also referred to as “UV crosslinking”) is performed, it is preferable to add a photopolymerization initiator.

As the photopolymerization initiator, either a cleavage type photopolymerization initiator or a hydrogen abstraction type photopolymerization initiator may be used, but both may be used in combination.
Examples of the cleavage type photopolymerization initiator include benzoin butyl ether, benzyl dimethyl ketal, and hydroxyacetophenone.
On the other hand, examples of the hydrogen abstraction type photopolymerization initiator include benzophenone, Michler's ketone, dibenzosuberone, 2-ethylanthraquinone, isobutylthioxanthone and the like.
However, it is not limited to the substances listed above.

  The photopolymerization initiator in the hard coat resin composition and the photopolymerization initiator in the pressure-sensitive adhesive resin composition may be the same or different. Among them, from the viewpoint of allowing both the hard coat layer and the pressure-sensitive adhesive layer to sufficiently cure even when the type of the light source in the ultraviolet irradiation step is single, the irradiation light source species It is preferable to use the same photopolymerization initiator having a light absorption capability corresponding to the emission wavelength.

  The addition amount of the photopolymerization initiator may be adjusted as appropriate, but generally it is better to adjust within a range of 0.05 to 5.0 parts by mass with respect to 100 parts by mass of the main component resin. It is preferable to use both the drawing type and the cleavage type photopolymerization initiators in a ratio of 1: 1. However, this range may be exceeded in balance with other elements.

  In addition to the above components, pigments such as pigments and dyes having near-infrared absorption characteristics, tackifiers, antioxidants, antioxidants, hygroscopic agents, ultraviolet absorbers, silane coupling agents, natural products, Various additives such as synthetic resins, glass fibers and glass beads can be appropriately blended.

  The above transparent pressure-sensitive adhesive layer is prepared by adding an acrylic resin as a main component resin and, if necessary, adding a crosslinking agent and a reaction initiator or a reaction catalyst, stirring and mixing them, and forming a desired thickness on the release film. A transparent adhesive layer can be obtained by forming a film as described above and crosslinking by heat drying or ultraviolet irradiation.

(Formation of adhesive pre-layer)
The pressure-sensitive adhesive resin composition is applied to the back surface of the hard coat preliminary layer obtained in the step, and dried or heated as necessary to form a pressure-sensitive adhesive preliminary layer.
Moreover, you may make it form an adhesive preliminary layer by affixing the adhesive sheet formed by shape | molding an adhesive resin composition on the back surface of this hard-coat preliminary layer.

<Two-layer simultaneous curing process>
In this step, light is irradiated from the back side of the pressure-sensitive adhesive pre-layer formed in the step, so that the hard-coat pre-layer hard coat resin composition and the pressure-sensitive adhesive pre-layer pressure-sensitive adhesive resin composition are simultaneously irradiated. Harden.

  As the irradiation light, energy rays such as an electron beam, radiation, and ultraviolet rays may be irradiated. Among these, from the viewpoint of molding time and productivity, curing by ultraviolet irradiation is preferable.

Integrated light quantity of a two-layer co-curing process, in the case of UV irradiation, for example, it is preferable to irradiate the ultraviolet rays of 200~10000mJ / cm ^2, inter alia 400 mJ / cm ² or more, or 6000 mJ / cm ² or less, among which It is even more preferable to irradiate ultraviolet rays of 1000 mJ / cm ² or more or 4000 mJ / cm ² or less.

  Here, as the light source that emits ultraviolet rays, for example, an electrodeless high-pressure mercury lamp, an electroded high-pressure mercury lamp, an electrodeless metal halide lamp, an electroded metal halide lamp, a xenon lamp, an ultrahigh-pressure mercury lamp, or a mercury xenon lamp can be used. Among these, an electrodeless high-pressure mercury lamp is preferable because it can easily obtain ultraviolet rays with high illuminance and is advantageous for curing an ultraviolet curable resin.

  When the hard coat resin composition is made of an ultraviolet curable resin and is cured by irradiating with ultraviolet rays, since the transparency to the ultraviolet rays is high, the internal curing of the curable resin composition proceeds quickly, but curing with oxygen. Due to an inhibitory action (referred to as oxygen injury), curing may be delayed on the surface of the curable resin composition. For this oxygen disorder, it is preferable to irradiate the resin composition with a nitrogen gas atmosphere by supplying nitrogen gas and then irradiate with ultraviolet rays, since the curing of the surface can proceed rapidly together with the inside of the resin composition. .

<Further processing>
The surface of the front plate resin base material may be subjected to any one or more of antireflection treatment, antifouling treatment, antistatic treatment, weather resistance treatment and antiglare treatment.
Each processing method is not particularly limited, and a known method can be used. For example, a method of applying a reflection reducing coating, a method of depositing a dielectric thin film, a method of applying an antistatic coating, and the like can be exemplified.

<Laminated structure in the laminate with the pressure-sensitive adhesive layer>
The laminate with the pressure-sensitive adhesive layer produced by the production method is configured by laminating a hard coat layer on at least the back surface of the front plate resin base material, and further laminating a transparent pressure-sensitive adhesive layer on the back surface of the hard coat layer. As long as it has. Therefore, another layer may be further provided. For example, the thing of the structure formed by laminating | stacking a hard-coat layer on both surfaces of a front plate resin base material may be sufficient.

(Thickness of front plate resin substrate)
In the laminate with the pressure-sensitive adhesive layer, the thickness of the front plate resin base material is not particularly limited. For example, the thickness is preferably 0.1 mm to 3.0 mm, particularly 1.5 mm or less, and more preferably 0.15 mm or more or 1.2 mm or less.
Among them, when applied to the front cover material of various image display devices, the thickness of the front plate resin base material is preferably 0.5 to 1.5 mm, and more preferably 0.6 mm or more or 1.2 mm or less. Of these, 0.7 mm or more or 1.1 mm or less is more preferable. If it is in this range, it is preferable because it is excellent in lightness and rigidity and shape stability in a high temperature and high humidity environment.

  In addition, when the adhesive layer is laminated on this laminate to protect it from being stained or scratched on the surface of glass, etc., or to prevent scattering of broken pieces, the front plate resin base The thickness of the material is preferably 0.1 mm to 0.6 mm, and more preferably 0.15 mm or more or 0.5 mm or less.

In the laminate with the pressure-sensitive adhesive layer, the thickness of the hard coat layer is not particularly limited. For example, the thickness is preferably 1 μm to 30 μm, more preferably 3 μm or more and 25 μm or less, particularly preferably 5 μm or more and 20 μm or less, and particularly preferably 7 μm or more or 15 μm or less.
Here, it is preferable if the thickness of the hard coat layer is in the above range because scratch resistance can be imparted and cracks due to stress are unlikely to occur.

  Moreover, when forming a hard-coat layer on both surfaces of a front-plate resin base material, the thickness of each hard-coat layer may be the same and may differ. Especially, it is preferable that the thickness of each hard-coat layer is the range of 7 micrometers-15 micrometers.

  On the other hand, the thickness of the transparent pressure-sensitive adhesive layer is preferably 10 μm to 300 μm from the viewpoint of reducing the internal stress of the laminate with the pressure-sensitive adhesive layer and improving the shape stability in a high-temperature and high-humidity environment. Alternatively, it is particularly preferably 250 μm or less, and particularly preferably 50 μm or more or 200 μm or less.

<Use of the laminate with the pressure-sensitive adhesive layer>
As described above, the laminate with the pressure-sensitive adhesive layer is excellent in shape stability in a high-temperature and high-humidity environment, and can also have transparency, impact resistance, surface hardness, and the like. Therefore, this laminated body with an adhesive layer can be used suitably as various board | substrate materials, protective materials, etc. by sticking together to various uses, for example, a base material. For example, in addition to various substrate materials and protective materials as constituent materials for image display devices such as mobile phone terminals, smartphones, portable electronic playground equipment, portable information terminals, tablet devices, mobile personal computers, wearable terminals, liquid crystal televisions, liquid crystal monitors, desktops It can be suitably used as various substrate materials and protective materials as constituent materials for stationary display devices such as personal computers, car navigation systems, and automobile meters.

  The laminate with the pressure-sensitive adhesive layer can also be given a shape by various processing methods. For example, in addition to the method of heating and pressurizing using a mold, a pressure forming method, a vacuum forming method, a roll homing method and the like can be exemplified as the forming method. By imparting a shape to the laminate, it can be used for an image display device having a curved surface and various flexible devices.

<Explanation of phrases>
“Sheet” generally refers to a product that is thin by definition in JIS and has a thickness that is small and flat for the length and width. In general, “film” is thicker than the length and width. A thin flat product with an extremely small thickness and an arbitrarily limited maximum thickness, usually supplied in the form of a roll (Japanese Industrial Standard JISK6900). However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the present invention, in the present invention, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. In some cases, “film” is included.
In addition, the expression “panel” such as an image display panel and a protection panel includes a plate, a sheet and a film, or a laminate thereof.

In the present specification, when “X to Y” (X and Y are arbitrary numbers) is described, it means “preferably greater than X” or “preferably,” with the meaning of “X to Y” unless otherwise specified. The meaning of “smaller than Y” is also included.
Further, when described as “X or more” (X is an arbitrary number), it means “preferably larger than X” unless otherwise specified, and described as “Y or less” (Y is an arbitrary number). In the case, unless otherwise specified, the meaning of “preferably smaller than Y” is included.

  Examples will be described in more detail below. However, the present invention is not limited to the examples described below.

<Examples and comparative examples>
The main raw materials and materials used in Examples and Comparative Examples will be described.

(Acrylic resin (a1-1))
Acrylic resin (Mitsubishi Rayon Co., Ltd., trade name: Acrypet VH001, density: 1.19 g / cm ³ , methyl methacrylate / methyl acrylate = 99/1% by mass, stereoregularity (triad fraction): mm (9.2 mol%), mr (41.8 mol%), rr (49.0 mol%), Tg: 111 ° C., MFR (temperature: 230 ° C., load: 37.3 N): 2.0 g / 10 min)

(Acrylic resin (a2-1))
Copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Regisphi R-100, density: 1.14 g / cm ³ , styrene / methyl methacrylate / maleic anhydride = 75/15/10% by mass, Tg: 127 ° C., MFR (temperature: 230 ° C., load: 37.3 N): 4.2 g / 10 min)

(Polycarbonate resin (b1-1))
Product name: Caliber 301-15, density: 1.20 g / cm ³ , Tg: 149 ° C., MFR (temperature: 300 ° C., load: 11.8 N): 15.0 g / 10 min, manufactured by Sumika Stylon Polycarbonate Co., Ltd. )

(Hard coat resin composition (c-1))
Organic / inorganic composite curable resin composition comprising a curable resin composed of a polyfunctional acrylate polymer and an inorganic component as a photopolymerization initiator (manufactured by MOMENTIVE, trade name “UVHC7800G”, photopolymerization initiator: 1 -Hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Japan Ltd., trade name: Irgacure 184)

(Hard coat resin composition (c-2))
Organic / inorganic composite curable resin composition (Atomics, “Compolide HUV IM-557RP”, After Cure, made by adding a photopolymerization initiator as an inorganic component to a curable resin comprising an alkoxysilane-containing acrylate polymer. Type coating agent, photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Japan Ltd., trade name: Irgacure 184)

(Adhesive sheet)
As an adhesive sheet, an adhesive resin comprising an acrylic ester copolymer, a crosslinking agent and a photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone (trade name; Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) The composition was sandwiched between two exfoliated polyethylene terephthalate films and formed into a sheet shape having a thickness of 150 μm.

(Glass plate)
A commercially available soda lime glass (width: 100 mm × length: 100 mm × thickness: 0.5 mm) was used as the glass plate.

<Example 1>
100 parts by mass of a resin composition obtained by mixing 60 parts by mass of acrylic resin (a1-1) and 40 parts by mass of copolymer acrylic resin (a2-1), and polycarbonate resin (b1-1) 100 Each mass part is supplied to separate extruders having a vent function and a filter function, melt-kneaded at a resin temperature of 240 to 265 ° C., and (acrylic resin layer) / (polycarbonate resin layer) is laminated with a feed block After co-extrusion with a 260 ° C. T-die so as to be configured, the first cooling roll set at 100 ° C., the second cooling roll set at 110 ° C., and the third cooling roll set at 150 ° C. in order The total thickness is 0.575 mm, and each layer thickness is (acrylic resin layer (A layer)) / (polycarbonate resin layer (B layer)) = 0.070 mm / 0.500 m. To obtain a front panel resin substrate is.

Next, a hard coat resin composition consisting of 100 parts by mass of the hard coat resin composition (c-1) was applied to the surface of the acrylic resin layer (A layer) of the front plate resin base material using a bar coater. Then, after drying at 90 ° C. for 1 minute in that state, the curable resin composition (c) is cured by exposing it to ultraviolet light with an integrated light amount of 700 mJ / cm ^{2 with} a high-pressure mercury lamp, A hard coat layer (Cf) was formed on the acrylic resin layer (A layer) of the material.

Next, a hard coat resin composition consisting of 100 parts by mass of the hard coat resin composition (c-2) was applied to the surface of the polycarbonate resin layer (B layer) of the front plate resin base material using a bar coater. In that state, it is dried at 90 ° C. for 1 minute to form a hard coat preliminary layer (Cb) to produce a resin laminate having a laminate structure of (Cf) / (A) / (B) / (Cb) did. At this stage, ultraviolet irradiation was not performed, and the hard coat preliminary layer (Cb) was in an uncured state.
Next, in the above resin laminate, the adhesive surface exposed by peeling one release film of the adhesive sheet is overlaid on the surface of the hard coat preliminary layer (Cb) of the resin laminate and adhered with a hand roller. Subsequently, the remaining release film was peeled off to form a pressure-sensitive adhesive preliminary layer, thereby forming a laminate.

Then, the laminated body is irradiated with ultraviolet light having an accumulated light amount of 2000 mJ / cm ² from the side of the pressure-sensitive adhesive preliminary layer, and the hard coat preliminary layer and the pressure-sensitive adhesive preliminary layer are simultaneously photocured. A laminate (sample) with a pressure-sensitive adhesive layer comprising a coat layer (Cf) / (A) / (B) / hard coat layer (Cb) / transparent pressure-sensitive adhesive layer was produced.
Furthermore, the adhesive surface of the transparent adhesive layer in the laminate with the adhesive layer (sample) is laminated on the surface of the glass plate and adhered with a hand roller, and then a resin laminate / transparent adhesive layer / glass laminate. (Bonding sample) was produced.

<Example 2>
In Example 1, when forming the hard coat preliminary layer (Cb), instead of the hard coat resin composition comprising 100 parts by mass of the hard coat resin composition (c-2), the hard coat resin composition (c-1) 100 is used. A laminate with a pressure-sensitive adhesive layer (sample), and a resin laminate / transparent adhesive, in the same manner as in Example 1, except that a hard coat preliminary layer (Cb) was formed using a hard coat resin composition comprising parts by mass. An agent layer / glass laminate (bonding sample) was prepared.

<Comparative Example 1>
In Example 1, after producing a resin laminate having a laminated structure of (Cf) / (A) / (B) / (Cb), an ultraviolet ray with an accumulated light amount of 700 mJ / cm ² was irradiated by a high-pressure mercury lamp. The hard coat preliminary layer (Cb) was cured.
Next, in the above resin laminate, the pressure-sensitive adhesive surface exposed by peeling off one release film of the pressure-sensitive adhesive sheet is superimposed on the surface after the hard coat preliminary layer (Cb) of the resin laminate is cured, and then a hand roller Then, the remaining release film was peeled off to form an adhesive preparatory layer to form a laminate.

Then, the laminated body is irradiated with ultraviolet rays having an accumulated light amount of 2000 mJ / cm ² from the pressure-sensitive adhesive preliminary layer side to cure the pressure-sensitive adhesive preliminary layer, and the hard coat layer (Cf) / (A) A laminate (sample) with an adhesive layer composed of / (B) / hard coat layer (Cb) / transparent adhesive layer was produced.
Furthermore, it carried out similarly to Example 1, and produced the resin laminated body / transparent adhesive layer / glass laminated body (bonding sample).

<Comparative Example 2>
In Example 2, after producing a resin laminate having a laminate structure of (Cf) / (A) / (B) / (Cb), ultraviolet rays having an accumulated light amount of 700 mJ / cm ² were irradiated by a high-pressure mercury lamp. The hard coat preliminary layer (Cb) was cured.
Next, in the above resin laminate, the pressure-sensitive adhesive surface exposed by peeling off one release film of the pressure-sensitive adhesive sheet is superimposed on the surface after the hard coat preliminary layer (Cb) of the resin laminate is cured, and then a hand roller Then, the remaining release film was peeled off to form an adhesive preparatory layer to form a laminate.

Then, the laminated body is irradiated with ultraviolet rays having an accumulated light amount of 2000 mJ / cm ² from the pressure-sensitive adhesive preliminary layer side to cure the pressure-sensitive adhesive preliminary layer, and the hard coat layer (Cf) / (A) A laminate (sample) with an adhesive layer composed of / (B) / hard coat layer (Cb) / transparent adhesive layer was produced.
Furthermore, it carried out similarly to Example 1, and produced the resin laminated body / transparent adhesive layer / glass laminated body (bonding sample).

<Evaluation test>
About the laminated body with an adhesive layer (sample) or resin laminated body / adhesive sheet / glass laminated body (bonding sample) obtained by the Example and the comparative example, the evaluation test was done as follows.

(1) Adhesive strength test About the laminated body (sample) with an adhesive layer obtained in the Example and the comparative example, using a tensile testing machine (205X by Intesco Corp.) under the condition of a tensile speed of 200 mm / min. The pressure-sensitive adhesive sheet was peeled off from the hard coat layer (Cb) in the 180 ° direction, and the adhesive strength between the pressure-sensitive adhesive sheet and the hard coat layer (Cb) was measured. The sample width was 10 mm.

(2) Moist heat exposure test of resin laminate / adhesive sheet / glass plate laminate The resin laminate / adhesive sheet / glass plate laminate (bonded sample) obtained in Examples and Comparative Examples was heated at 85 ° C. and humidity 85. Immediately after being left in a constant temperature and humidity chamber set at% RH for 120 hours and then left in a constant temperature and humidity chamber set at a temperature of 23 ° C. and a humidity of 50% RH for 4 hours, the appearance of the test piece was visually observed. .

At this time, if the adhesive strength between the front plate resin substrate and the transparent pressure-sensitive adhesive layer is not sufficient, peeling occurs at the interface between the front plate and the pressure-sensitive adhesive sheet, resulting in poor appearance due to air bubbles (air) mixing in the peeled location. The size of the defective appearance portion was visually measured and evaluated according to the following criteria.
○ (good): Area ratio of appearance defective part is less than 10% × (poor): Area ratio of appearance defective part is 10% or more

From Table 1, the back side hard coat layer is bonded to the transparent pressure-sensitive adhesive layer in an uncured or semi-cured state, and the hard coat layer and the transparent pressure-sensitive adhesive layer are simultaneously irradiated with ultraviolet rays to be cured, thereby increasing the adhesive strength. It has been found that the appearance after exposure to a wet heat environment can also be improved.
Also, by using an after-cure type coating agent as the hard coat resin composition, it becomes easy to handle the back side hard coat layer while suppressing the appearance defect while remaining uncured. It turned out that it can respond also to the case where storage and transportation are required in an uncured state, such as when the layer bonding step is a separate step. However, it was found that even a coating agent other than the after-curing type can be used without problems when the production of the back hard coat layer and the bonding of the pressure-sensitive adhesive layer are continuous steps.

From the above examples and test results conducted by the inventors so far, a hard coat preliminary layer is formed on the back surface of the front plate resin base material, and the hard coat resin composition and the adhesive resin composition are bonded together to form both resin compositions. If the product is photocured at the same time, not only can the adhesive strength between the hard coat layer and the transparent adhesive layer be increased, but also the peeling of the hard coat layer and the transparent adhesive layer in a high temperature and high humidity environment can be suppressed. I understood.
In addition, when forming the hard coat preliminary layer, without irradiating the photocurable hard coat resin composition with ultraviolet rays, until the hard coat preliminary layer is formed only in the drying process and two layers are simultaneously cured, It has been found that it is preferable to leave the photocurable hard coat resin composition in an uncured state.

  The adhesive strength between the hard coat layer and the transparent adhesive layer can be increased by simultaneously curing the hard coat resin composition and the adhesive resin composition with the acrylic monomer of the hard coat layer and the transparent adhesive. It can be inferred that the crosslinking reaction of the agent layer with the acrylic monomer proceeds and the adhesive strength between the hard coat layer and the transparent adhesive layer increases.

Claims (2)

A pressure-sensitive adhesive having a constitution in which a hard coat layer is provided on at least the back surface of a resin base material of the front plate (referred to as “front plate resin base material”), and a transparent pressure-sensitive adhesive layer is further laminated on the back surface of the hard coat layer. In the method for producing a layered laminate,
A hard coat resin composition is attached to the back surface of the front plate resin base material to form a hard coat preliminary layer, and then a photo curable adhesive resin composition is attached to the back surface of the hard coat preliminary layer. To form a pre-adhesive layer, and then irradiate light from the back side of the pre-adhesive layer to form a hard coat resin composition for the pre-hard coat layer and an adhesive resin composition for the pre-adhesive layer A method for producing a laminate with a pressure-sensitive adhesive layer, characterized by simultaneously photocuring a product.   After forming the hard coat preliminary layer as described above, the photocurable adhesive resin composition is attached to the back surface of the hard coat preliminary layer without passing through the step of UV curing the hard coat preliminary layer. The method for producing a laminate with a pressure-sensitive adhesive layer according to claim 1, wherein an agent preliminary layer is formed.