JP6976063B2 - Laminated sheet - Google Patents

Description

The present invention relates to a laminated sheet, and more particularly to a laminated sheet suitable for an application of firmly joining or fixing an adherend having a rough surface.

Generally, a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive; the same applies hereinafter) exhibits a soft solid state (viscous elastic body) in a temperature range near room temperature, and has a property of adhering to an adherend by pressure. Taking advantage of these properties, the pressure-sensitive adhesive is, for example, in the form of a pressure-sensitive adhesive sheet (laminated sheet) having a resin layer capable of functioning as a pressure-sensitive adhesive on one or both sides of a base material, from home appliances to automobiles, OA equipment, and the like. Widely used in various industrial fields. Patent Documents 1 to 3 are mentioned as technical documents relating to the pressure-sensitive adhesive sheet.

Japanese Unexamined Patent Publication No. 08-104847 Japanese Unexamined Patent Publication No. 2012-251143 Japanese Unexamined Patent Publication No. 2010-120114

However, the conventional adhesive sheet has an adhesive force to an adherend having a rough surface (surface having an uneven shape) such as concrete, mortar, gypsum board, softwood plywood, wood-based cement board, calcium silicate board, etc. It tended to be in short supply. For this reason, adhesives are often used for mutual joining of adherends having these rough surfaces and for fixing to other adherends. In recent years, with the increasing need for easier joining and fixing of adherends having these rough surfaces, an adhesive sheet capable of firmly adhering to the adherend having these rough surfaces has been required. ing.

Patent Document 1 discloses an adhesive sheet provided with a rubber-based adhesive layer, which exhibits good adhesive force to an adherend having a rough surface such as concrete. However, in order to form the rubber-based pressure-sensitive adhesive layer, curing is required after the rubber-based pressure-sensitive adhesive is applied, and there is a concern about a problem from the viewpoint of production efficiency. Further, since the rubber-based pressure-sensitive adhesive contains a certain amount or more of the pressure-sensitive adhesive as an essential component, there is a concern that the adhesive strength may decrease at low temperatures. Patent Document 2 discloses a double-sided adhesive tape having an acrylic pressure-sensitive adhesive layer containing an acrylic polymer obtained by photopolymerization on both sides of a polyethylene foam base material, but an adherend having a rough surface as described above. Adhesive strength to is not considered. Patent Document 3 is a document relating to a waterproof single-sided adhesive tape that can be used as an alternative to a liquid sealing material, and is not intended for strong adhesion to a rough surface.

The present invention has been made in view of such a situation, and is a laminated sheet capable of firmly adhering to an adherend having a rough surface and firmly fixing the adherend. The purpose is to provide.

According to this specification, a laminated sheet including a porous base material and a resin layer provided on at least one side of the porous base material is provided. The porous substrate has a 25% compression hardness of 1.00 MPa or less. Further, the resin layer contains an acrylic polymer which is a polymer of a monomer component containing the monomer a1 and the monomer a2. Here, the monomer a1 is an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms at the end of the ester group. The monomer a2 consists of a (meth) acrylate having a chain ether bond in the molecular skeleton and an alkyl (meth) acrylate having a branched alkyl group having 15 to 20 carbon atoms at the end of the ester group. At least one of the choices. The monomer component typically contains 50 to 97% by weight of the monomer a1 and 3 to 50% by weight of the monomer a2. The tensile breaking strength of the laminated sheet is 0.9 MPa or more.

A porous substrate having a 25% compressive hardness limited to the above value or less has high flexibility and easily absorbs irregularities on the surface of an adherend, for example. According to the laminated sheet having the above configuration provided with the resin layer having the above composition on such a porous substrate, the surface of the resin layer is adhered well to the adherend, and the cohesive force of the resin layer and the adherend to the adherend are obtained. Adhesiveness can be suitably compatible. Further, since the laminated sheet has a tensile breaking strength equal to or higher than a predetermined value, the bonded state between the adherend and the laminated sheet is impaired by the internal fracture of the laminated sheet (particularly the destruction of the porous substrate). Highly resistant. Combined with these actions, according to the laminated sheet, the adherend having a rough surface can be firmly joined or fixed.

In some embodiments, the monomer a1 may comprise an alkyl (meth) acrylate having an alkyl group having 8-14 carbon atoms (preferably a branched alkyl group) at the end of the ester group. The technique disclosed herein can be suitably carried out in an embodiment using such a monomer a1.

In some embodiments, the resin layer preferably has a storage elastic modulus G'at 23 ° C. of 5.0 × 10 ⁴ Pa or less. In the present specification, the storage elastic modulus G'means the storage elastic modulus G'at 23 ° C., unless otherwise specified. When the storage elastic modulus G'of the resin layer becomes low, the deformability of the resin layer tends to improve. As a result, the followability (adhesion) of the resin layer to the unevenness of the rough surface can be improved in a shorter time, and high adhesive strength can be exhibited from the initial stage after the laminated sheet is attached. The lower limit of the storage elastic modulus G'of the resin layer is not particularly limited, but it is usually appropriate to set it to ^{1.0 × 10 4 Pa or more in consideration of the balance with the cohesive force.}

The laminated sheet disclosed herein can be preferably carried out in the form of a laminated sheet in which the resin layer is provided on either one side or the opposite side of the porous base material. In some embodiments, the laminated sheet may have a shear adhesion of 3.0 × 10 ⁵ N / m ² or more after 72 hours of application. According to such a laminated sheet, an adherend having a rough surface such as a gypsum board or a calcium silicate board can be reliably joined or fixed for a long period of time. The shear adhesive force is measured under the condition of a tensile speed of 50 mm / min, and more specifically, it is measured by the method described in Examples described later.

The laminated sheet according to some preferred embodiments has a relationship between the tensile breaking strength Ta (unit: Pa, in an environment of 23 ° C.) of the laminated sheet and the storage elastic modulus G'(unit: Pa) of the resin layer. The following equation: 10 ≦ Ta / G'; is satisfied. Laminated sheets with Ta / G'above or equal to a predetermined value adhere well to the rough surface from an early stage, and peel off from the rough surface due to fracture inside the laminated sheet (particularly inside the porous substrate). It can be difficult to occur.

As the porous base material, a stretchable base material having an elongation at break of 120% or more and 1000% or less can be preferably adopted. In a laminated sheet having such a porous base material, the energy required for deformation of the porous base material acts as a resistance to peeling, so that the peel strength from the adherend can be improved. The porous substrate contains, for example, at least one resin selected from the group consisting of a polyolefin resin, a polyurethane resin, a polyimide resin, a polyether resin, a polyester resin and a polyacrylic resin. It can be preferably adopted.

The monomer component is a (meth) acrylate having a chain ether bond in the molecular skeleton as the monomer a2, and has a general formula (1):
CH ₂ = CR ^1- COO- (AO) _n- R ² ;
It is preferable to contain a monomer represented by. Here, in the above general formula (1), R ¹ is a hydrogen atom or a methyl group. AO is an alkyleneoxy group having 2 to 3 carbon atoms. n is a number indicating the average number of moles of the alkyleneoxy group added, and is preferably about 1 to 8. R ² is a monovalent organic group, typically a group selected from the group consisting of aryl groups, linear or branched alkyl groups, and alicyclic alkyl groups. According to such a monomer a2, it is easy to suitably balance the cohesive force of the resin layer and the adhesiveness to the adherend.

The monomer component may further contain at least one functional group-containing monomer selected from the group consisting of a monomer having a hydroxyl group, a monomer having a carboxy group, and a monomer having an epoxy group. Such a functional group-containing monomer can be useful for adjusting the cohesive force and the storage elastic modulus G'of the resin layer.

The glass transition temperature (Tg) of the acrylic polymer is preferably −40 ° C. or lower. When the Tg of the acrylic polymer is low, the rough surface adhesive strength of the resin layer tends to increase. This is preferable from the viewpoint of improving the initial adhesiveness to the rough surface.

In some embodiments, the weight average molecular weight of the acrylic polymer (Mw) of is preferably 35 × 10 ⁴ or more. According to the acrylic polymer having such Mw, it is easy to obtain a resin layer having both the followability to the unevenness of the rough surface and the cohesive force.

The resin layer may contain a cross-linking agent. The cross-linking agent may be useful for adjusting the cohesive force of the resin layer and the storage elastic modulus G'. The amount of the cross-linking agent used can be, for example, about 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer. As the cross-linking agent, one or both of the isocyanate-based cross-linking agent and the epoxy-based cross-linking agent can be preferably used.

The gel fraction of the resin layer is preferably in the range of 20 to 95% by weight. According to such a resin layer, it is easy to suitably balance the adhesive force with the rough surface and the holding force.

The laminated sheet according to some preferred embodiments has a 180 ° peel strength of 6 N / 20 mm or more after 30 minutes of application to gypsum board and calcium silicate board. For example, the 180 ° peel strength after 30 minutes of application to gypsum board, calcium silicate board, and softwood plywood can all be 6N / 20 mm or more. According to the technique disclosed herein, it is possible to realize a laminated sheet that firmly adheres to the rough surface from the initial stage after being attached.

According to this specification, the adherend having a rough surface and any of the laminated sheets disclosed herein are included, and the resin layer adheres to the rough surface to form the adherend and the laminated sheet. A laminated structure in which is integrated is provided. Such a laminated structure is suitable for an application of being fixed to another adherend via, for example, the laminated sheet.

It should be noted that a combination of the above-mentioned elements as appropriate may be included in the scope of the invention for which protection by the patent is sought by the present patent application.

It is sectional drawing which shows typically the structure of the laminated sheet which concerns on one Embodiment. It is sectional drawing which shows typically the structure of the laminated sheet which concerns on another embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for the practice of the present invention are based on the teachings regarding the practice of the invention described in the present specification and the common general knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in the present specification and the common general technical knowledge in the art.
In the following drawings, members / parts having the same function may be described with the same reference numerals, and duplicate description may be omitted or simplified. In addition, the embodiments described in the drawings are schematically for the purpose of clearly explaining the present invention, and do not necessarily accurately represent the size or scale of the actually provided product.

As used herein, the term "(meth) acrylate" is meant to collectively refer to acrylates and methacrylates. Similarly, in the present specification, "(meth) acrylic acid" means acrylic acid and methacrylic acid, and "(meth) acryloyl group" means acryloyl group and methacrylic acid group, respectively.

<Porous medium>
The laminated sheet disclosed herein includes a porous base material (that is, a base material having a porous structure) on the back surface side (the side opposite to the surface to be attached to the adherend) of the resin layer. As a result, the unevenness of the surface of the adherend can be absorbed by the deformation of the porous base material, and the resin layer with respect to the surface of the adherend can be better followed. The porous base material referred to here may be a base material having voids inside, and the material and structure are not particularly limited. For example, the voids inside the porous substrate may be bubbles or capsules (hollow particles) dispersed in the base material, or may be gaps between particle aggregates and fiber aggregates. The bubble may be an open cell, a closed cell, or an intermediate or complex structure thereof. Further, the porous substrate may have a single-layer (single-layer) structure or a multi-layer structure of two or more layers. In the porous substrate having a multi-layer structure, the material and structure (porosity, average pore size, etc.) of each layer may be the same or different. From the viewpoint of cost reduction and prevention of destruction at the interlayer interface of the porous substrate, the porous substrate having a single layer structure can be preferably adopted in some embodiments. Hereinafter, the porous base material may be simply referred to as a "base material".

The constituent material of the porous base material can be appropriately selected as long as it does not impair the handleability of the laminated sheet, and is not particularly limited. Examples of the constituent material of the porous base material include plastic materials such as thermoplastic resins, thermosetting resins, and elastomers; natural fibers such as pulp, linen, cotton, and wool, and inorganic fibers such as metal fibers and glass fibers. Fiber material; etc. can be used. Examples of the above plastic materials include olefin resins such as polyethylene (PE) and polypropylene (PP); polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate (PBT); polystyrene and the like. Polystyrene resin; Vinyl resin such as polyvinyl chloride; Polyurethane resin; Acrylic resin such as polymethylmethacrylate; Polyurethane such as ether polyurethane, ester polyurethane, carbonate polyurethane, acrylic-urethane copolymer, etc. Polyurethane-based resin; Cellulos-based resin; Polycarbonate-based resin; Polyamide-based resin; Polyimide-based resin; Polyether-based resin such as polyether ether ketone; Polyethyleneimide-based resin; Polysulfone-based resin; Fluorine-based resin; Rubber-based polymer; etc. Can be mentioned. A plastic film or sheet mainly composed of these plastic materials can be preferably used as the porous base material.

The porous substrate may be formed by any method. For example, a porous film obtained by casting a polymer solution into a film and then guiding it to a coagulating liquid, a porous film obtained by stretching treatment, and a film mixed with removal fine particles are removed from the fine particles by elution treatment or the like. Using a porous film obtained by embossing a film, a porous film obtained by fusing a polymer powder under heating, a chemical foaming agent or a physical foaming agent. A foamed foam film, a film in which a hollow filler such as a heat-expandable microsphere or a hollow glass bead is dispersed, or the like can be used as a porous base material of the laminated sheet disclosed herein. The average particle size of the hollow glass beads can be appropriately selected in consideration of the thickness of the porous substrate and the like, but is generally 1 to 500 μm, preferably 3 to 400 μm. Further, the average particle size of the heat-expandable microspheres can be appropriately set in consideration of the thickness of the porous substrate and the like, and is, for example, 1 to 500 μm, preferably 3 to 400 μm after thermal expansion.

In some embodiments, a porous substrate comprising a foam layer formed of a foam of plastic material (plastic foam) may be preferably employed. Specific examples of the plastic foam include a polyolefin resin foam; a polyester resin foam; a polyvinyl chloride resin foam; a vinyl acetate resin foam; a polyphenylene sulfide resin foam; an aliphatic polyamide (nylon) resin foam. Body, amide resin foam such as total aromatic polyamide (aramid) resin foam; polyimide resin foam; polyether ether ketone (PEEK) foam; styrene resin foam such as polystyrene foam; polyurethane Urethane-based resin foams such as resin foams; and the like. Further, as the plastic foam, a rubber-based resin foam such as a foam made of polychloroprene rubber may be used.

As a preferable foam, a polyolefin-based resin foam (hereinafter, also referred to as “polyolefin-based foam”) is exemplified. As the plastic material (that is, the polyolefin-based resin) constituting the polyolefin-based foam, various known or commonly used polyolefin-based resins can be used without particular limitation. Examples thereof include polyethylene such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer and the like. .. Examples of LLDPE include Ziegler-Natta catalytic linear low density polyethylene, metallocene catalytic linear low density polyethylene and the like. As the polyolefin resin, one kind may be used alone or two or more kinds may be used in combination as appropriate. In some embodiments, a polyolefin-based foam substantially composed of a polyethylene-based resin or a foam of a polypropylene-based resin may be preferably adopted as the porous substrate or a component thereof. Here, the polyethylene-based resin refers to a resin containing ethylene as a main monomer (that is, the main component of the monomer), and in addition to HDPE, LDPE, LLDPE, etc., ethylene in which the copolymerization ratio of ethylene exceeds 50% by weight- It may include a propylene copolymer, an ethylene-vinyl acetate copolymer and the like. Similarly, the polypropylene-based resin refers to a resin containing propylene as a main monomer. Of these, polyethylene-based foam is preferable.

The method for producing the polyolefin-based foam as described above is not particularly limited, and various known methods can be appropriately adopted. From the viewpoint of improving the strength of the base material, a manufacturing method including a crosslinking step can be preferably adopted. For example, it can be produced by a method including a molding step, a crosslinking step and a foaming step of the corresponding polyolefin resin. In addition, a stretching step may be included if necessary. Examples of the method for cross-linking a polyolefin-based foam include a chemical cross-linking method using an organic peroxide or the like, an ionizing radiation cross-linking method for irradiating ionizing radiation, and the like, and these methods can be used in combination. Examples of the ionizing radiation include electron beams, α rays, β rays, and γ rays. The dose of ionizing radiation is not particularly limited, and an appropriate irradiation dose can be set in consideration of the target physical properties (for example, the degree of cross-linking) of the porous substrate.

(25% compression hardness of base material)
The porous substrate constituting the laminated sheet disclosed herein, 25% compressive hardness 0.10MPa and (i.e., 1.00 × ¹⁰ 6 Pa) not more than is preferably used. When the 25% compressive hardness of the porous substrate is lowered, the flexibility of the porous substrate is increased, and the followability to unevenness (unevenness absorption) tends to be improved. By arranging such a flexible porous base material on the back surface side of the resin layer, the surface of the resin layer can be adhered well to the adherend, and the cohesive force of the resin layer and the adhesiveness to the adherend can be obtained. Can be suitably compatible with each other.

Here, the 25% compressive hardness of the porous base material means that the base material is cut into a square shape of 30 mm square and stacked to make a measurement sample having a thickness of about 2 mm, and the measurement sample is sandwiched between a pair of flat plates. It refers to the load when compressed by the thickness corresponding to 25% of the thickness (load at a compression rate of 25%). That is, it refers to the load when the measurement sample is compressed to a thickness corresponding to 75% of the initial thickness. The 25% compressive hardness of the substrate is measured according to JIS K6767. As a specific measurement procedure, the measurement sample is set in the center of the pair of flat plates, and the flat plates are continuously compressed to a compression rate of 25% by narrowing the space between the flat plates, and the flat plates are stopped at 20. Measure the load after a second. The same method is used in the examples described later. The 25% compressive hardness of the porous substrate can be controlled, for example, by selecting the material of the substrate, adjusting the degree of cross-linking, adjusting the apparent density, adjusting the size and structure of the voids, and the like.

From the viewpoint of further enhancing the unevenness absorption, in some embodiments, the 25% compressive hardness of the substrate may be, for example, 1.00 MPa or less, 0.50 MPa or less, or 0.30 MPa or less. The laminated sheet disclosed herein can also be preferably carried out in an embodiment in which a substrate having a 25% compressive hardness of 0.25 MPa or less or 0.20 MPa or less (for example, a foam sheet) is used. The lower limit of the 25% compressive hardness of the base material is not particularly limited, and it is sufficient that a laminated sheet exhibiting a tensile breaking strength Ta of a predetermined value or higher can be constructed. From the viewpoint of facilitating the construction of a laminated sheet exhibiting such tensile breaking strength Ta, in some embodiments, the 25% compressive hardness of the substrate may be, for example, 0.02 MPa or more, or 0.03 MPa or more. .. The laminated sheet disclosed herein can also be preferably carried out in an embodiment in which a substrate having a 25% compressive hardness of 0.04 MPa or more (for example, a foam sheet) is used.

(Elongation when the base material breaks)
As the porous base material constituting the laminated sheet disclosed herein, a stretchable base material can be preferably adopted. By using the elastic base material, the stress applied to the laminated sheet can be appropriately dispersed. As a result, it is possible to suppress the occurrence of bonding defects due to internal destruction of the laminated sheet (particularly destruction of the base material), and to firmly and reliably bond or fix the adherend having a rough surface. In an embodiment using a stretchable base material, the elongation at break (also referred to as elongation at break) of the base material may be, for example, 50% or more, usually 100% or more is appropriate, and 120% or more. Is preferable. In some embodiments, the elongation at break of the substrate may be, for example, 150% or more, 170% or more, 200% or more, or 220% or more. The upper limit of elongation at break is not particularly limited, but from the viewpoint of availability of materials and balance with other physical properties, 1500% or less is usually suitable, 1200% or less, 1000% or less, 800. It may be less than%.

The elongation at break of the base material is obtained from the chuck distance L1 when the test piece is broken and the chuck distance L0 at the start of pulling by pulling the test piece made of the base material at a speed of 500 mm / min according to JIS K6767. The following formula:
Elongation at break (%) = ((L1-L0) / L0) × 100;
Is required by. Here, L0 is 40 mm. It is preferable that the tensile direction in the above test coincides with the longitudinal direction (which may be the flow direction (MD) of the base material) of the long base material. The elongation at break of the base material can be controlled, for example, by selecting the material of the base material, adjusting the degree of cross-linking, adjusting the apparent density, the size and structure of the voids, and the like.

In the laminated sheet disclosed herein, the influence of the resin layer on the elongation at break of the laminated sheet (obtained in the same manner as the elongation at break of the base material except that the laminated sheet is used as a test piece) is usually obtained. Extremely small. Therefore, when it is difficult to obtain a base material before forming the resin layer, the value of the elongation at break of the laminated sheet, that is, as an alternative value of the elongation at break of the base material or at least a sufficiently approximate value for practical use, that is, Using the laminated sheet as a test piece, the value of elongation at break obtained in the same manner as described above can be used. Further, the above-mentioned preferable range of the elongation at break of the base material can be grasped as the preferable range of the elongation at break of the laminated sheet.

(Tension breaking strength Ts of the base material)
The tensile breaking strength Ts of the base material is not particularly limited, and can be set so as to obtain a desired tensile breaking strength Ta in, for example, a laminated sheet including the base material. The tensile breaking strength Ta (unit: Pa, in an environment of 23 ° C.) of the base material is a test in which a test piece made of the base material is pulled at a rate of 500 mm / min according to the tensile strength measuring method specified in JIS K6767. It is calculated by dividing the load F (unit: N) when the piece is broken by the cross-sectional area A (unit: m ^{2) of the base material.} As will be described later, in the technique disclosed here, the tensile breaking strength Ts of the base material and the tensile breaking strength Ta of the laminated sheet can be roughly equated with each other. Can also be applied to the tensile breaking strength Ts of the base material.

The thickness of the base material is not particularly limited, and can be appropriately set according to the strength and flexibility of the base material, the purpose of use of the laminated sheet, and the like. From the viewpoint of improving the unevenness absorption, the thickness of the base material may be, for example, 20 μm or more, usually 50 μm or more, 70 μm or more, 100 μm or more, or 200 μm or more. In some embodiments, the thickness of the substrate may be 300 μm or more, or 500 μm or more. Further, from the viewpoint of reducing the thickness and weight of the laminated sheet, the thickness of the base material may be, for example, 10 mm or less, 5 mm or less, 3 mm or less, or 2 mm or less.

The porosity (volume basis) of the base material is not particularly limited. The porosity of the substrate can be appropriately set, for example, so as to obtain the desired 25% compressive hardness. The porosity of the base material is usually 95% or less, preferably 90% or less, 85% or less, or 80% or less. As the porosity of the substrate becomes smaller, the tensile breaking strength Ts tends to improve. Further, from the viewpoint of improving the unevenness followability, the porosity of the base material is usually preferably 3% or more, preferably 10% or more, and may be 20% or more. In some embodiments, the porosity of the substrate may be, for example, 25% or higher, 35% or higher, or 40% or higher. The porosity of the base material can be calculated based on the true specific gravity of the base material constituting material and the apparent volume of the base material. The above-mentioned porosity value of the base material can be preferably applied, for example, when a plastic foam (for example, a polyolefin-based foam) is used as the base material.

The density of the base material (referred to as an apparent density; hereinafter the same unless otherwise specified) is not particularly limited and may be ^{, for example, 0.03 to 0.9 g / cm 3.} From the viewpoint of weight reduction of the laminated sheet and improvement of unevenness absorption, the density of the base material may be, for example, 0.8 g / cm ³ or less, 0.7 g / cm ³ or less, or 0 in some embodiments. .6g / cm ³ may be below, may be 0.5 g / cm ³ or less, may be 0.4 g / cm ³ or less. From the viewpoint of easily increasing the tensile strength at break Ts of the substrate, the density of the substrate is usually suitably 0.04 g / cm ³ or more may be 0.05 g / cm ³ or more, 0.06 g / It may be cm ³ or more, 0.07 g / cm ³ or more, 0.10 g / cm ³ or more, or 0.11 g / cm ³ or more. The density (apparent density) of the base material can be measured in accordance with JIS K6767. The above-mentioned density value of the base material can be preferably applied, for example, when a plastic foam (for example, a polyolefin-based foam) is used as the base material.

When a plastic foam (for example, a polyolefin-based foam) is used as the base material, the average cell diameter of the foam is not particularly limited. From the viewpoint of facilitating both a 25% compressive strength of a predetermined value or less and a tensile breaking strength Ts of a predetermined value or more, in some embodiments, a plastic foam having an average cell diameter of 400 μm or less (for example, 200 μm or less, or 100 μm or less) is used. It can be preferably used. Further, from the viewpoint of improving the unevenness absorption, a plastic foam having an average cell diameter of 10 μm or more (for example, 30 μm or more, or 40 μm or more) can be preferably used. The average cell diameter referred to here is a true sphere-equivalent average cell diameter obtained by observing the cross section of the foam substrate with an electron microscope. The average cell diameter in each direction of the foam base material is controlled, for example, by adjusting the composition of the foam base material (the amount of the foaming agent used, etc.) and the production conditions (conditions in the foaming step, stretching step, etc.). be able to.

The base material may be a filler (inorganic filler, organic filler, etc.), a colorant such as a pigment or a dye, an antioxidant, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, or a plasticizer, if necessary. Various additives such as agents, flame retardants, and surfactants may be blended.

On the surface of the base material on which the resin layer is placed, if necessary, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, undercoating agent (primer) application, antistatic treatment, etc. Conventionally known surface treatment may be applied. Such a surface treatment may be a treatment for improving the adhesion between the base material and the resin layer, in other words, the anchoring property of the resin layer on the base material. The composition of the undercoat is not particularly limited and can be appropriately selected from known ones. The coating thickness of the undercoating agent is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm.

In the case of a laminated sheet in which the resin layer is arranged only on one side (front surface) of the base material, conventionally known methods such as peeling treatment and antistatic treatment are performed on the opposite surface (back surface) of the base material, if necessary. It may be surface-treated. For example, by surface-treating the back surface of the base material with a release treatment agent (typically, by providing a release layer with a release treatment agent), the rewinding force of the laminated sheet in the form of being wound in a roll shape can be obtained. Can be lightened. As the stripping agent, a silicone-based stripping agent, a long-chain alkyl-based stripping agent, an olefin-based stripping agent, a fluorine-based stripping agent, a fatty acid amide-based stripping agent, molybdenum sulfide, silica powder, or the like can be used. .. Further, for the purpose of improving the layering property, the back surface of the base material may be subjected to treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, and alkali treatment. Among them, corona discharge treatment and plasma treatment can be preferably applied from the viewpoint of productivity.

<Resin layer>
The resin layer of the laminated sheet disclosed herein contains an acrylic polymer which is a polymer of a monomer component containing a monomer a1 and a monomer a2. Here, the monomer a1 is an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms at the end of the ester group. The monomer a2 has (i) a (meth) acrylate having a chain ether bond in the molecular skeleton, and (ii) an alkyl (meth) acrylate having a branched alkyl group having 15 to 20 carbon atoms at the end of the ester group. , At least one selected from the group consisting of. The content of the monomer a1 in the monomer component is preferably in the range of 50 to 97% by weight. The content of the monomer a2 in the monomer component is preferably in the range of 3 to 50% by weight. According to a laminated sheet having a resin layer containing an acrylic polymer having such a copolymerization composition on a porous substrate, an adherend having a rough surface can be firmly bonded or fixed. It is preferable that the resin layer exhibits a soft solid state (viscoelastic body) in a temperature range of around 23 ° C. and exhibits a property of adhering to an adherend by pressure. The resin layer in the technique disclosed herein can typically be a resin layer formed from a material that functions as a pressure-sensitive adhesive. That is, in the typical example of the laminated sheet disclosed here, the resin layer can be grasped as an adhesive layer.
In the following, "the number of carbon atoms _{X to Y} " may be referred to as "CXY", and "the number of carbon atoms X" _{may be referred to as "CX".} Further, there may be referred to as "alkyl having an alkyl group having a carbon number X~Y the end of the ester group-containing (meth) acrylate" and "C _X-Y alkyl (meth) acrylate", a chain in a "molecular scaffold "(Meta) acrylate having a state ether bond" may be referred to as "chain ether bond-containing (meth) acrylate".

(Monomer a1)
As the monomer a1, C _4-14 alkyl (meth) acrylate is used. The alkyl group at the end of the ester group of the monomer a1 may be linear or branched. The number of carbon atoms of the alkyl group is preferably 6 or more, and more preferably 8 or more, from the viewpoint of imparting appropriate softness to the resin layer and enhancing the cohesive force of the resin layer. From the same viewpoint, the number of carbon atoms of the alkyl group is preferably 12 or less, and more preferably 10 or less. Further, it is more preferable that the alkyl group is branched. The monomer a1 can be used alone or in combination of two or more.

_{Specific examples of the C 4-14} alkyl (meth) acrylate that can be used as the monomer a1 include, for example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, and t-butyl (meth). Acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, n-hexyl (meth) acrylate, isohexyl (meth) acrylate, n-heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl ( Meta) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, n-undecyl (meth) Acrylate, Isoundecyl (meth) acrylate, n-dodecyl (meth) acrylate, isododecyl (meth) acrylate, n-tridecyl (meth) acrylate, isotridecyl (meth) acrylate, n-myristyl (meth) acrylate, isomyristyl (meth) acrylate And so on.

From the viewpoint of enhancing the adhesive strength of the resin layer, the viewpoint of polymerization reactivity, and the like, C _4-14 alkyl acrylate can be preferably used as the monomer a1. Specific examples include butyl acrylate (BA; Tg = -55 ° C.), n-hexyl acrylate, isohexyl acrylate, 2-ethylhexyl acrylate (2EHA; Tg = -70 ° C.), n-octyl acrylate, and isooctyl acrylate (Tg). = -58 ° C), n-nonyl acrylate, isononyl acrylate (Tg = -58 ° C), n-decyl acrylate, isodecyl acrylate (Tg = -60 ° C), n-undecyl acrylate, isoundecyl acrylate, n -Dodecyl acrylate, isododecyl acrylate, isomyristyl acrylate (Tg = −56 ° C.) and the like can be mentioned.

In some embodiments, the monomer a1 may preferably be an alkyl (meth) acrylate having a homopolymer Tg of −50 ° C. or lower (more preferably −55 ° C. or lower, still more preferably −60 ° C. or lower). By using the monomer a1 having a low Tg of the homopolymer, the unevenness-following property of the resin layer with respect to the rough surface can be improved. The lower limit of Tg of the homopolymer of the monomer a1 is not particularly limited, but from the viewpoint of availability, it is usually appropriate to be −80 ° C. or higher, and preferably −75 ° C. or higher.

In the techniques disclosed herein, the Tg of the homopolymer of each monomer is the numerical value described in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). If a plurality of numerical values are described in the Polymer Handbook, the conventional value is adopted. For the monomer not described in the Polymer Handbook, the catalog value of the monomer manufacturing company is adopted.

As the Tg of the homopolymer of the monomer which is not described in the above Polymer Handbook and the catalog value of the monomer manufacturing company is not provided, the value obtained by the following measuring method is used. That is, in a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser, 100 parts by weight of the monomer to be measured, 0.1 part by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization solvent were added. Add and stir for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 60 ° C. and the reaction is carried out for 12 hours. Then, the homopolymer solution is cooled to room temperature, the homopolymer solution is cast-coated on a release liner, and dried to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 50 μm. Collect 2 to 3 mg of the obtained sample, put it in an aluminum container, crimp it, and perform DSC measurement (Q-2000 manufactured by TA Instruments). The temperature program is -80 ° C to 150 ° C (measurement speed 10 ° C / min), and the measurement is performed under nitrogen (50 ml / min) atmospheric gas. The value of Tmg (midpoint glass transition temperature) is read from the obtained chart, and this value is taken as Tg of the homopolymer.

As the monomer a1 in the technique disclosed herein, a C _4-14 alkyl (meth) acrylate _{having a branched alkyl group at the end of the ester group (typically a branched C 6-14} alkyl (meth) acrylate, for example. Branched C _8-14 alkyl (meth) acrylate) can be preferably used. Of these, branched _C8-14 alkyl acrylates are preferable.

When two or more compounds are used as the monomer a1, at least one of them has a Tg of (A) homopolymer of −50 ° C. or lower (more preferably −55 ° C. or lower, still more preferably −60 ° C. or lower). , And (B) a branched alkyl (meth) acrylate, preferably an alkyl (meth) acrylate satisfying at least one (preferably both). The proportion of the alkyl (meth) acrylate satisfying the above conditions (A) and / or (B) in the monomer a1 contained in the monomer component may be, for example, 50% by weight or more, 70% by weight or more, and 85% by weight. It may be% or more. In some preferred embodiments, the total amount of the monomer a1 may be an alkyl (meth) acrylate that satisfies the above conditions (A) and / or (B).

In the embodiment in which two or more kinds of alkyl (meth) acrylates are used as the monomer a1, the composition of the monomer a1 is set so that the Tg of the acrylic polymer A1 which is a polymer of the monomer a1 is −40 ° C. or lower. Is desirable. As described above, according to the monomer a1 having a composition of giving the acrylic polymer A1 having a Tg of −40 ° C. or lower, a resin layer that easily follows the unevenness of the rough surface tends to be formed. In some embodiments, the composition of the monomer a1 can be set so that the Tg of the acrylic polymer A1 is −50 ° C. or lower (more preferably −55 ° C. or lower, still more preferably −60 ° C. or lower). ..

In the present specification, the Tg of the polymer is based on the composition of the monomer component constituting the polymer (for example, in the acrylic polymer A1 which is a polymer of the monomer a1, based on the composition of the monomer a1). It refers to Tg as a theoretical value obtained by the Fox equation. As shown below, the Fox formula is a relational formula between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer.
1 / Tg = Σ (Wi / Tgi)
In the Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on the weight), and Tgi is the homopolymer of the monomer i. Represents the glass transition temperature (unit: K) of. The Tg of the polymer can be adjusted by selecting the monomer contained in the monomer component constituting the polymer, the weight fraction of each monomer in the entire monomer component, and the like.

(Monomer a2)
As the monomer a2, at least one selected from the group consisting of a chain ether bond-containing (meth) acrylate and a branched C _{15-20 alkyl (meth) acrylate is used.}

[Chain ether bond-containing (meth) acrylate]
As the chain ether bond-containing (meth) acrylate, one or more (meth) acrylates containing a (meth) acryloyl group and a chain ether bond in one molecule can be used without particular limitation. The chain ether bond means an ether bond that does not form a ring structure, unlike a cyclic ether bond such as an epoxy group or an oxetane group.

Examples of the chain ether bond-containing (meth) acrylate that can be used as the monomer a2 include a monomer represented by _{the general formula (1): CH 2} = CR ¹ −COO− (AO) _n −R ^{2 ;.} Here, in the above general formula (1), R ¹ is a hydrogen atom or a methyl group, and AO is an alkyleneoxy group of _{C 2-3.} R ² is a linear or branched alkyl group or an alicyclic alkyl group. That is, R ² is a group that does not contain an ether bond. n indicates the average number of moles of the alkyleneoxy group added, and is typically 1 to 8.

As an example of the monomer represented by the general formula (1), glycol (meth) acrylate having an oxyethylene group having an average addition molar number of 1 to 8, specifically, methoxypolyethylene glycol (meth) acrylate and ethoxypolyethylene glycol ( Examples thereof include meta) acrylate and propoxypolyethylene glycol (meth) acrylate. As another example of the monomer represented by the general formula (1), glycol (meth) acrylate having an oxypropylene group having an average addition molar number of 1 to 8, specifically, methoxypolypropylene glycol (meth) acrylate and ethoxypolypropylene. Glycol (meth) acrylate, propoxypolypropylene glycol (meth) acrylate and the like can be mentioned.

As the AO in the general formula (1), an oxyethylene group (that is, an alkyleneoxy group having 2 carbon atoms) is preferable from the viewpoint of having an appropriate polar balance. Further, n in the general formula (1) is preferably 2 to 8 and more preferably 2 to 5 from the viewpoint of the polarity level and the polymerization reactivity.

^{R 2} in the general formula (1) can be selected from an aryl group, a linear alkyl group, a branched chain alkyl group, and an alicyclic alkyl group. As ^{the aryl group of R 2} , an unsubstituted aromatic ring such as a phenyl group or a naphthyl group is preferable. Linear alkyl as the methyl group of R ^2, ethyl group, propyl group or the like; branched-chain alkyl as the group isopropyl, isobutyl and the like; and the like; a cycloheptyl group, a cyclohexyl group, etc. The alicyclic alkyl group .. Since liable to Tg lower chain ether bond-containing (meth) acrylate homopolymer, it is preferred that R ² is a straight chain alkyl group or branched alkyl group, particularly preferably a straight chain alkyl group. Further, since the likely monomers a2 having moderate polarity, carbon atoms ^{R 2} is preferably from 1 to 6, more preferably 1-5 or 1-4, 1-3 or 1 It is more preferably ~ 2.

In some embodiments, the monomer a2 contains a chain ether bond having a homopolymer Tg of −40 ° C. or lower (more preferably −45 ° C. or lower, still more preferably −50 ° C. or lower, for example −55 ° C. or lower). (Meta) acrylates can be preferably used. By using a chain ether bond-containing (meth) acrylate having a low Tg of the homopolymer, the unevenness-following property of the resin layer with respect to the rough surface can be improved. The lower limit of Tg of the homopolymer of the chain ether bond-containing (meth) acrylate used as the monomer a2 is not particularly limited, but is preferably −90 ° C. or higher from the viewpoint of enhancing the adhesive force and holding power to the rough surface. More preferably, it is -80 ° C or higher. Specific examples of the chain ether bond-containing (meth) acrylate that can be preferably used as the monomer a2 include ethyl carbitol acrylate (also known as ethoxyethoxyethyl acrylate) (Tg = -67 ° C.) and methoxytriethylene glycol acrylate (Tg =-). 57 ° C.) and the like.

When two or more kinds of chain ether bond-containing (meth) acrylates are used as the monomer a2, at least one of them has a Tg of (C) homopolymer of −40 ° C. or lower (more preferably −45 ° C. or lower, more preferably −45 ° C. or lower). Is preferably a chain ether bond-containing (meth) acrylate that satisfies the above (-50 ° C or lower). The proportion of the chain ether bond-containing (meth) acrylate satisfying the above condition (C) in the monomer a2 contained in the monomer component may be, for example, 50% by weight or more, 70% by weight or more, or 85% by weight or more. But it may be. In some preferred embodiments, the total amount of the monomer a2 may be a chain ether bond-containing (meth) acrylate satisfying the above (C).

[Branched C _15-20 alkyl (meth) acrylate]
A non-limiting example of the above-mentioned branched C _15-20 alkyl (meth) acrylate (that is, an alkyl (meth) acrylate having a branched alkyl group having 15 to 20 carbon atoms at the end of an ester group) is isopenta. Decyl acrylate, isopentadecyl methacrylate, isohexadecyl acrylate, isohexadecyl methacrylate, isoheptadecyl acrylate, isoheptadecyl methacrylate, isostearyl acrylate (18 carbon atoms, homopolymer Tg = -18 ° C), isostearyl methacrylate, Examples thereof include isononadecyl acrylate, isononadecyl methacrylate, isoeicocil acrylate and isoeicocil methacrylate. The branched C _15-20 alkyl (meth) acrylate may be used alone or in combination of two or more. As the branched C _{15-20 alkyl (meth) acrylate, a branched C 15-20} alkyl acrylate can be preferably adopted from the viewpoint of enhancing the adhesive strength of the resin layer and the viewpoint of polymerization reactivity. The number of carbon atoms of the branched alkyl group is preferably 15 to 18.

The Tg of the homopolymer of the branched C _15-20 alkyl (meth) acrylate is −30 ° C. or higher and 20 ° C. or lower from the viewpoint of enhancing the adhesive force of the resin layer and imparting an appropriate cohesive force to the resin layer. Is preferable. The Tg of the homopolymer of the branched C _15-20 alkyl (meth) acrylate is more preferably 15 ° C. or lower, further preferably 10 ° C. or lower, from the viewpoint of enhancing the adhesive strength of the resin layer. It is more preferably −28 ° C. or higher, and even more preferably −25 ° C. or higher.

The amount of the monomer a1 used can be, for example, 50 to 97% by weight with respect to all the monomer components forming the acrylic polymer. From the viewpoint of enhancing the unevenness followability to the adherend having a rough surface, in some embodiments, the amount of the monomer a1 used may be 52% by weight or more, 55% by weight or more, or 60% by weight of all the monomer components. It may be 70% by weight or more, 65% by weight or more, 70% by weight or more, or 75% by weight or more. Further, from the viewpoint of better exerting the effect of using the monomer a1 and the monomer a2 in combination, in some embodiments, the amount of the monomer a1 used may be 95% by weight or less of the total monomer components. It may be 93% by weight or less, 90% by weight or less, or 85% by weight or less.

The amount of the monomer a2 used can be, for example, 3 to 50% by weight based on all the monomer components forming the acrylic polymer. From the viewpoint of enhancing the adhesive force and the holding force to the adherend having a rough surface, in some embodiments, the amount of the monomer a2 used may be 4% by weight or more of all the monomer components, or 7% by weight or more. It may be 10% by weight or more, or 13% by weight or more. Further, from the viewpoint of polymerization reactivity and the like, in some embodiments, the amount of the monomer a2 used may be 48% by weight or less, 45% by weight or less, or 40% by weight or less of all the monomer components. It may be 35% by weight or less, 30% by weight or less, or 25% by weight or less.

As the monomer a2, only one kind or two or more kinds of chain ether bond-containing (meth) acrylates may be used, or only one kind or two or more kinds of _{branched C 15-20 alkyl (meth) acrylates may be used.} Further, a chain ether bond-containing (meth) acrylate and a branched C _15-20 alkyl (meth) acrylate may be used in combination. In that case, the weight ratio of the chain ether bond-containing (meth) acrylate to the branched C _15-20 alkyl (meth) acrylate (chain ether bond-containing (meth) acrylate / branched C _15-20 alkyl (meth) acrylate) is For example, it may be 5/95 to 95/5, 10/90 to 90/10, or 25/75 to 75/25.

As a preferred example of the resin layer in the laminated sheet disclosed herein, a C _4-14 alkyl (meth) acrylate having a homopolymer Tg of −50 ° C. or lower (for example, a homopolymer Tg of −50 ° C. or lower) is used. C _8-14 comprise branched alkyl acrylate) and 50 to 97 wt%, and the polymerization of the monomer component Tg comprises a chain ether bond-containing at -40 ℃ below (meth) acrylate 3-50% by weight of the homopolymer Examples thereof include a resin layer containing an acrylic polymer having a Tg of −40 ° C. or lower.

The ratio of the total amount of the monomer a1 and the monomer a2 to the total amount of the monomer components may be, for example, 55% by weight or more, 60% by weight or more, and usually 75% by weight or more. preferable. From the viewpoint of enhancing the adhesive force and the holding force to the adherend having a rough surface, in some embodiments, the total amount of the monomer a1 and the monomer a2 may be 80% by weight or more of the total monomer component, and is 85% by weight. % Or more, more preferably 90% by weight or more. The technique disclosed herein can also be suitably carried out in an embodiment in which the total amount of the monomer a1 and the monomer a2 is 95% by weight or more or 97% by weight or more of the total amount of the monomer components.

(Monomer containing functional groups)
The monomer component forming the acrylic polymer is at least one functional group selected from the group consisting of a monomer having a hydroxyl group, a monomer having a carboxy group, and a monomer having an epoxy group, in addition to the above-mentioned monomers a1 and a2. It may contain a contained monomer. The monomer component may contain, for example, a monomer having a hydroxyl group and a monomer having a carboxy group in combination.

Examples of the monomer having a hydroxyl group (hydroxyl-containing monomer) include 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 6-Hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and other hydroxyalkyl (meth) acrylates; (4-hydroxymethyl) Hydroxyalkylcycloalkano (meth) acrylates such as cyclohexyl) methyl (meth) acrylates may be mentioned. In addition, one or more selected from hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like can be used. Of these, hydroxyalkyl (meth) acrylates are preferable, and 2-hydroxyethyl (meth) acrylates and 4-hydroxybutyl (meth) acrylates are particularly preferable.

Examples of the monomer having a carboxy group (monomer containing a carboxy group) include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. One or more selected from acids and the like may be used. Of these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable.

The monomer having an epoxy group (epoxy group-containing monomer) is selected from, for example, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like. One or more can be used.

When the monomer component forming the acrylic polymer contains a hydroxyl group-containing monomer, the content thereof is preferably 0.01% by weight or more of the entire monomer component, and 0.03% by weight, from the viewpoint of enhancing the cohesive force. % Or more is more preferable. The amount of the hydroxyl group-containing monomer used is preferably 20% by weight or less, preferably 15% by weight or less, from the viewpoint of suppressing an excessive increase in viscosity or gelation of the polymer. It is more preferably 10% by weight or less. In some embodiments, the amount of the hydroxyl group-containing monomer used may be, for example, 5% by weight or less of the total monomer component, preferably 3% by weight or less, and more preferably 2% by weight or less. ..

When the monomer component forming the acrylic polymer contains a carboxy group-containing monomer, the content thereof is the monomer component from the viewpoint of enhancing the cohesive force and imparting the interaction with the surface of the adherend at the molecular level. It is preferably 0.1% by weight or more, and more preferably 0.2% by weight or more of the whole. It is appropriate that the amount of the carboxy group-containing monomer used is 10% by weight or less of the total amount of the monomer components from the viewpoint of enhancing the followability to the rough surface and maintaining the adhesive strength at low temperature. It is preferably 1% by weight or less, more preferably 3% by weight or less, and further preferably 2% by weight or less.

When the monomer component forming the acrylic polymer contains an epoxy group-containing monomer, the content thereof is preferably 0.1% by weight or more of the entire monomer component from the viewpoint of enhancing the cohesive force, and is 0.2. More preferably, it is by weight% or more. The amount of the epoxy group-containing monomer used is preferably 1% by weight or less, and more preferably 0.5% by weight or less of the total amount of the monomer components from the viewpoint of suppressing gelation and high viscosity. This does not apply when the acrylic polymer is a graft polymer.

When a hydroxyl group-containing monomer and a carboxy group-containing monomer are used in combination as the functional group-containing monomer, the weight ratio of the hydroxyl group-containing monomer to the carboxy group-containing monomer (hydroxyl group-containing monomer / carboxy group-containing monomer) is an adherend having a rough surface. From the viewpoint of enhancing the adhesive force to the body, 0.01 or more is preferable, 0.02 or more is more preferable, 1.0 or less is preferable, and 0.50 or less is more preferable.

(Copolymerization monomer)
In addition to the above-mentioned monomers a1 and a2, the monomer component forming the acrylic polymer may contain a copolymerized monomer other than the above-mentioned functional group-containing monomer (excluding those corresponding to the monomer a1 or the monomer a2). .. Such a copolymerization monomer may be used as a component of a monomer component together with the functional group-containing monomer, or may be used as a component of a monomer component having a composition not containing the functional group-containing monomer.

The copolymerized monomer is, for example, _{a monomer represented by the general formula (2): CH 2} = CR ^3- COO-R ⁴ ; (however, any of the above-mentioned monomers a1, monomer a2, and functional group-containing monomer). Applicable ones are excluded.) Can be used. Here, in the above general formula (2), R ³ is a hydrogen atom or a methyl group, and R ⁴ is a C _1-24 , unsubstituted or substituted monovalent hydrocarbon group. The hydrocarbon group may or may not contain an unsaturated bond (eg, a double bond). The copolymerization monomer may be used alone or in combination of two or more.

^{R 4} in the above general formula (2) is C _1-24 (preferably C _1-18 ), for example, an unsubstituted or substituted alkyl group or an unsubstituted or substituted alicyclic. It can be an alkyl group of the formula. In some embodiments, R ⁴ can be a linear alkyl group of _{C 1-18 , a branched alkyl group of C 3-7} , an alicyclic alkyl group of C _4-24 , and the like. When R ⁴ is substituted alkyl or substituted alicyclic alkyl group, the substituent may, for example, an aryl group of C _6-12, aryl group having C _6-12, may be equal. The aryl group is not particularly limited, but for example, a phenyl group is preferable.

Examples of the monomer represented by the general formula (2) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-pentadecyl (meth) acrylate. n-hexadecyl (meth) acrylate, n-heptadecyl (meth) acrylate, n-stearyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 3 , 3,5-trimethylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, terpene (meth) acrylate, dicyclopentanyl (meth) acrylate and the like.

Further, as the copolymerization monomer, for example, vinyl-based monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylcaprolactam, N-vinylpyrrolidone; tetrahydrofurfuryl (meth) acrylate, fluorine (meth). ) Acrylate-based monomers such as acrylates, silicone (meth) acrylates and 2-methoxyethyl acrylates; monomers having nitrogen atom-containing groups such as amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, and N-acryloylmorpholin. ; Vinyl ether monomer; etc. may be used.

Further, as the above-mentioned copolymerization monomer, a silane-based monomer containing a silicon atom may be used. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-vinyloctyloxydecyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

In the present invention, the copolymerization monomer is preferably 20% by weight or less, more preferably 15% by weight or less, based on all the monomer components forming the acrylic polymer. If the content of the copolymerization monomer exceeds 20% by weight, for example, the adhesiveness to the rough surface may decrease.

(Polyfunctional monomer)
The monomer component forming the acrylic polymer may contain a polyfunctional monomer, if necessary, in order to adjust the cohesive force of the resin composition. The polyfunctional monomer may be used alone or in combination of two or more.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups ((meth) acryloyl group, vinyl group, etc.) having an unsaturated double bond, and is, for example, a (poly) ethylene glycol di (meth) acrylate. , (Poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2- Ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethyl propanetri (meth) acrylate, tetramethylol methanetri (meth) acrylate, etc. Polyhydric alcohol and (meth) acrylic acid ester compound; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldi (meth) acrylate, hexyldi (meth) acrylate. And so on. Of these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate are preferable.

The polyfunctional monomer can be used in an amount of 5% by weight or less based on all the monomer components forming the acrylic polymer. The polyfunctional monomer varies depending on its molecular weight, the number of functional groups, and the like, but is preferably 3% by weight or less, more preferably 2% by weight or less, based on all the monomer components forming the acrylic polymer. If the content of the polyfunctional monomer exceeds 5% by weight, for example, the crosslink density and elastic modulus of the resin composition may become too high, and the adhesive strength may decrease.
The Tg of the acrylic polymer obtained from the monomer component containing the polyfunctional monomer is the Tg and the weight of the homopolymer of each monomer other than the polyfunctional monomer in the total amount of the monomer components other than the polyfunctional monomer. It shall be calculated based on the fraction.

Although not particularly limited, the weight ratio of the monomer a1 and the monomer a2 (monomer a1: monomer a2) contained in the monomer component is usually preferably in the range of 50:50 to 97: 3. It is preferably in the range of 55:45 to 97: 3. In some embodiments, the weight ratio (monomer a1: monomer a2) may be, for example, in the range of 60:40 to 95: 5, may be in the range of 70:30 to 93: 7, 75 :. It may be in the range of 25 to 93: 7. Each of the above-mentioned weight ratios is the total of the monomer a1 and the monomer a2 (for example, the sum of the monomers a1 and the monomer a2) when the monomer component is substantially composed of the monomer a1 and the monomer a2 even when the monomer component contains a monomer other than the monomer a1 and the monomer a2. It can also be preferably applied when the amount accounts for 98% by weight or more of the monomer component).

(Acrylic polymer)
The acrylic polymer contained in the resin layer of the laminated sheet disclosed herein is a polymer of a monomer component containing at least the monomer a1 and the monomer a2 as described above. The acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like. From the viewpoint of productivity and ease of production, the acrylic polymer is usually preferably a random copolymer.

The Tg of the above-mentioned acrylic polymer is not particularly limited and may be, for example, −30 ° C. or lower. In some embodiments, the Tg of the acrylic polymer is preferably −40 ° C. or lower, more preferably −45 ° C. or lower, and even more preferably −50 ° C. or lower. According to the Tg acrylic polymer, the adhesion of the resin layer to the rough surface can be efficiently improved. From this point of view, in the laminated sheet disclosed herein, the Tg of the acrylic polymer may be, for example, −55 ° C. or lower, −60 ° C. or lower, or −65 ° C. or lower. .. Further, the Tg of the acrylic polymer is preferably −85 ° C. or higher, and more preferably −80 ° C. or higher, from the viewpoint of enhancing the adhesive force and the holding force to the adherend having a rough surface.

The method for producing the above-mentioned acrylic polymer is not particularly limited, and a known production method can be appropriately selected. For example, various radical polymerizations such as solution polymerization, radiation polymerization by irradiation with electron beam or ultraviolet rays (UV), bulk polymerization, emulsion polymerization and the like can be used. For radical polymerization, a known polymerization initiator, chain transfer agent, emulsifier, polymerization solvent and the like can be used, if desired, depending on the mode of polymerization.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2-amidinopropane) dihydrochloride, and 2,2'-azobis [2- (5- (5-). Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutyramidin), Azo-based initiators such as 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057); potassium persulfate, ammonium persulfate, etc. Persulfate; di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t -Hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, Di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, hydrogen peroxide, etc. Oxide-based initiators; redox-based initiators in which peroxides and reducing agents are combined, such as a combination of persulfate and sodium hydrogen sulfite, a combination of peroxide and sodium ascorbate, etc. , Not limited to these. In some embodiments, AIBN may be preferably employed as the polymerization initiator. The polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably about 0.005 to 1 part by weight, more preferably about 0.01 to 0.5 part by weight, based on 100 parts by weight of the monomer component.

Further, when the monomer component is radiation-polymerized by UV irradiation, the monomer component can contain a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it initiates photopolymerization, and is, for example, a benzoin ether type, an acetophenone type, an α-ketol type, a photoactive oxime type, a benzoin type, a benzyl type, a benzophenone type, or a ketal. A known photopolymerization initiator such as a system or a thioxanthone system can be used. The photopolymerization initiator may be used alone or in combination of two or more. The amount of the photopolymerization initiator used is usually preferably 0.05 to 1.5 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the monomer component.

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol and the like. The chain transfer agent may be used alone or in combination of two or more. Generally, the amount of the chain transfer agent used is approximately 0.1 part by weight or less with respect to 100 parts by weight of the monomer component.

Emulsion polymerization of the monomer components is typically carried out using known emulsifiers. Examples of the emulsifier include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, polyoxyethylene alkyl ether ammonium sulfate, and sodium polyoxyethylene alkyl phenyl ether sulfate; polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether. , Polyoxyethylene fatty acid ester, nonionic emulsifier such as polyoxyethylene-polyoxypropylene block polymer; and the like can be preferably used. An emulsifier having a radically polymerizable functional group (propenyl group, allyl ether group, etc.), which is called a reactive emulsifier, may be used. The emulsifier may be used alone or in combination of two or more. The amount of the emulsifier used can be, for example, 0.3 to 5 parts by weight with respect to 100 parts by weight of the monomer component, and is preferably 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability.

Solution polymerization of the monomer component can be carried out using, for example, a polymerization solvent such as ethyl acetate or toluene. Although not particularly limited, the above solution polymerization is carried out, for example, under an inert gas stream such as nitrogen, using a polymerization initiator as described above, at a polymerization temperature of about 50 to 70 ° C., for 5 to 30 hours. It can be carried out under moderate reaction conditions.

The Mw of the acrylic polymer ^{is preferably 35 × 10 4 or more, more preferably 40 × 10 4} or more, and 50 × 10 ⁴ or more from the viewpoint of enhancing the durability and cohesive force of the resin layer. Is even more preferred. In some embodiments, the Mw of the acrylic polymer may be 60 × 10 ⁴ or more, 70 × 10 ⁴ or more, or 80 × 10 ⁴ or more. Mw of the acrylic polymer, in view enhances the combined resistance and adhesion bonding or viscosity of inhibition of the resin composition, it preferably at 300 × 10 ⁴ or less, 250 × 10 ⁴ or less more preferably, further preferably 200 × 10 ⁴ or less. In some embodiments, the Mw of the acrylic polymer ^{is preferably 150 × 10 4} or less, ^{more preferably 120 × 10 4} or less. The Mw of the acrylic polymer can be controlled, for example, by selecting and using a polymerization initiator, selecting and using a chain transfer agent, reaction conditions, and the like.

The Mw of the acrylic polymer can be calculated in terms of polystyrene based on GPC (gel permeation chromatography). As a sample for GPC, a filtrate obtained by dissolving the sample in tetrahydrofuran (THF) to prepare a 0.1% by weight solution, allowing it to stand overnight, and then filtering it with a 0.45 μm membrane filter is used. GPC can be performed under the following conditions or conditions in which equivalent results can be obtained. The same method is used in the examples described later.
・ Analytical device: HLC-8120GPC manufactured by Tosoh Corporation
-Column: Tosoh, GM7000H _XL + GMH _XL + GMH _XL
-Column size: 7.8 mmφ x 30 cm each, 90 cm in total
-Sample concentration: 0.1% by weight (THF solution)
-Eluent: THF
・ Flow rate: 0.8 ml / min ・ Inlet pressure: 1.6 MPa
-Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection amount: 100 μL
・ Standard sample: Polystyrene

The resin layer constituting the laminated sheet disclosed herein can be formed by using a resin composition containing such an acrylic polymer. The form of the resin composition is not particularly limited, and may be, for example, various forms such as an aqueous dispersion of a resin layer forming component, an organic solvent solution, a hot melt type, and a radiation curable type using an electron beam or UV.

In some embodiments, the proportion of the acrylic polymer in the resin layer may be, for example, more than 50% by weight, 70% by weight or more, or 85% by weight or more from the viewpoint of improving the adhesive force to the rough surface. However, it may be 90% by weight or more, or 95% by weight or more. The technique disclosed herein can also be preferably carried out in an embodiment in which 98% by weight or more of the resin layer is the above-mentioned acrylic polymer.

(Crosslinking agent)
The resin composition used for forming the resin layer may contain a cross-linking agent. Examples of the above-mentioned cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, silicone-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, silane-based cross-linking agents, alkyl etherified melamine-based cross-linking agents, and metal chelate-based cross-linking agents. Includes cross-linking agents such as agents and peroxides. Preferable examples of the above-mentioned cross-linking agent include an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent. An isocyanate-based cross-linking agent and an epoxy-based cross-linking agent may be used in combination.

The above-mentioned cross-linking agent may be used alone or in combination of two or more. The amount of the cross-linking agent used is preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer. The content of the cross-linking agent is more preferably 0.01 to 4 parts by weight, still more preferably 0.02 to 3 parts by weight.

As the isocyanate-based cross-linking agent, a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantification) can be used. .. Examples of the isocyanate-based cross-linking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, aliphatic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, the isocyanate-based cross-linking agent includes lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, and alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate. Aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylenepolyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Toso Co., Ltd., product) Isocyanate additions such as trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Toso Co., Ltd., trade name Coronate HL), isocyanurates of hexamethylene diisocyanate (manufactured by Toso Co., Ltd., trade name Coronate HX). , Trimethylol propane adduct of xylylene diisocyanate (manufactured by Mitsui Chemicals, trade name: Takenate D110N), Trimethylol propane adduct of xylylene diisocyanate (manufactured by Mitsui Chemicals, trade name: Takenate D120N), Trimethylol of isophorone diisocyanate Propane adduct (Mitsui Chemicals, trade name: Takenate D140N), Trimethylol propane adduct of hexamethylene diisocyanate (Mitsui Chemicals, trade name: Takenate D160N); polyether polyisocyanate, polyester polyisocyanate, and these Examples thereof include additions with various polyols, isocyanurate bonds, burette bonds, polyisocyanates polyfunctionalized by allophanate bonds and the like. Among these, it is preferable to use an aromatic isocyanate or an alicyclic isocyanate in order to develop the characteristics related to the adhesive force and the holding force in a well-balanced manner.

The isocyanate-based cross-linking agent may be used alone or in combination of two or more. The amount of the isocyanate-based cross-linking agent used can be, for example, about 0.01 to 5 parts by weight, 0.03 to 4 parts by weight, or 0.05 to 3 parts by weight with respect to 100 parts by weight of the acrylic polymer. It may be a part by weight or 0.08 to 2 parts by weight.

As the epoxy-based cross-linking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1, 6-Hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta Elythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, In addition to resorcin diglycidyl ether and bisphenol-S-diglycidyl ether, epoxy-based resins having two or more epoxy groups in the molecule can be mentioned. Examples of commercially available products of the epoxy-based cross-linking agent include trade names "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company.

The epoxy-based cross-linking agent may be used alone or in combination of two or more. The amount of the epoxy-based cross-linking agent used can be, for example, about 0.005 to 1 part by weight with respect to 100 parts by weight of the acrylic polymer, and 0.01 to 0.5 parts by weight or 0.015 to 0. It may be 4 parts by weight.

(Acrylic oligomer)
In addition to the above-mentioned acrylic polymer, an acrylic oligomer can be added to the resin composition used for forming the resin layer for the purpose of improving the adhesive strength and the like. Here, the acrylic oligomer means a polymer containing a monomer unit derived from an acrylic monomer in a polymer structure, and typically means a polymer containing the monomer unit in a proportion of more than 50% by weight. As the acrylic oligomer, it is preferable to use a polymer having a higher Tg and a lower Mw than the above-mentioned acrylic polymer. The Tg of the acrylic oligomer may be, for example, about 0 ° C. or higher and 300 ° C. or lower, about 20 ° C. or higher and 300 ° C. or lower, or about 40 ° C. or higher and 300 ° C. or lower. The Tg of the acrylic oligomer is a theoretical value calculated based on the Fox formula, like the Tg of the acrylic polymer. The Mw of the acrylic oligomer may be, for example, 1000 or more and less than 30,000, 1500 or more and less than 20,000, or 2,000 or more and less than 10,000. If Mw is too high, the initial adhesive strength may decrease. If Mw is too low, it tends to cause deterioration of shear adhesive force and holding characteristics. The Mw of the acrylic oligomer can be obtained as a polystyrene-equivalent value based on GPC. Specifically, it can be measured by using TSKgelGMH-H (20) × 2 as a column on HPLC8020 manufactured by Tosoh Corporation and using a THF solvent at a flow rate of about 0.5 ml / min.

Examples of the monomer constituting the acrylic oligomer include an alkyl (meth) acrylate having a linear or branched alkyl group of _{C 1-18} (preferably C _{1-12) at the end of the ester group; cyclohexyl (meth).} (Meta) acrylic acid esters of alicyclic alcohols such as acrylates, isobornyl (meth) acrylates, dicyclopentanyl (meth) acrylates; aryl (meth) acrylates such as phenyl (meth) acrylates, benzyl (meth) acrylates. (Meta) acrylate obtained from a terpene compound derivative alcohol; and the like. These can be used alone or in combination of two or more.

Examples of the acrylic oligomer include branched alkyl (meth) acrylates such as isobutyl (meth) acrylate and t-butyl (meth) acrylate; cyclohexyl (meth) acrylate and isobornyl (meth) acrylate dicyclopentanyl (meth) acrylate. It is represented by (meth) acrylate having a cyclic structure such as (meth) acrylic acid ester of alicyclic alcohol and aryl (meth) acrylate such as phenyl (meth) acrylate and benzyl (meth) acrylate. It is preferable that an acrylic monomer having a relatively bulky structure is contained as a monomer unit. By giving such a bulky structure to the acrylic oligomer, the adhesiveness of the resin layer can be further improved. In particular, those having a cyclic structure are highly effective in terms of bulkiness, and those containing a plurality of rings are even more effective. Further, when UV polymerization is used for synthesizing an acrylic oligomer or preparing a resin layer, an alcohol (meth) acrylic acid ester that does not contain an unsaturated bond is preferable because it is unlikely to cause polymerization inhibition. For example, a branched alkyl (meth) acrylate or a (meth) acrylic acid ester of an alicyclic alcohol can be suitably used as a monomer constituting an acrylic oligomer.

Preferable examples of the acrylic oligomer are cyclohexyl methacrylate (CHMA), dicyclopentanyl acrylate (DCPA), dicyclopentanyl methacrylate (DCPMA), isobornyl acrylate (IBXA), isobornyl methacrylate (IBXMA) 1-adamantyl. Homopolymers of acrylate (ADA) and 1-adamantyl methacrylate (ADAM); copolymer of CHMA and isobutyl methacrylate (IBMA), copolymer of CHMA and IBXMA, co-polymer of CHMA and acryloylmorpholine (ACMO) Polymers, polymers of CHMA and diethylacrylamide (DEAA), copolymers of ADA and methylmethacrylate (MMA), copolymers of DCPMA and IBXMA, copolymers of DCPMA and MMA; etc. be able to. In particular, an acrylic oligomer containing CHMA as a main component is preferable.

When an acrylic oligomer is used, the amount used is not particularly limited. From the viewpoint of avoiding the elasticity of the resin layer becoming too high, the amount of the acrylic oligomer used is appropriately 70 parts by weight or less (for example, 1 to 70 parts by weight) with respect to 100 parts by weight of the acrylic polymer. It is preferably 2 to 50 parts by weight, more preferably 3 to 40 parts by weight. The laminated sheet disclosed herein can be preferably carried out in a manner in which an acrylic oligomer is substantially not used in the resin layer.

(Adhesive-imparting resin)
The resin layer may contain a tackifier resin, if necessary, for the purpose of improving the interaction with the interface of the adherend and improving the cohesive force of the resin layer. Examples of the tackifier resin include phenol-based tackifier resins, terpene resins, modified terpene resins (terpenephenol resins, etc.) and rosin-based tackifier resins (unmodified rosin, rosin esters, their hydrogenated products, asymmetrical products, and polymers. Etc.), petroleum resin, styrene resin, kumaron-inden resin, ketone resin, etc., one or more selected from various known tackifier resins can be used. Preferable examples include a rosin-based tackifier resin such as a polymerized rosin ester and a terpene phenol resin. The amount of the tackifier resin used is preferably set within a range in which the elastic modulus of the resin layer does not become too high, and is usually 40 parts by weight or less (preferably 20 parts by weight or less, for example) with respect to 100 parts by weight of the acrylic polymer. 10 parts by weight or less) is preferable. The technique disclosed herein can be preferably carried out in a manner in which the resin layer does not substantially contain the tackifier resin.

(Silane coupling agent)
A known silane coupling agent can be added to the resin composition used for forming the resin layer, if necessary. This can improve the adhesive reliability and the adhesive force at the interface with the adherend. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4 epoxycyclohexyl) ethyltrimethoxy. Epyl group-containing silane coupling agent such as silane; 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl) Butylidene) Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane; (meth) acrylics such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane. Group-containing silane coupling agents; isocyanate group-containing silane coupling agents such as 3-isocyanoxide propyltriethoxysilane; and the like. The amount of the silane coupling agent to be used is preferably 1 part by weight or less, preferably 0.01 to 1 part by weight, and more preferably 0.02 to 0.6 part by weight with respect to 100 parts by weight of the acrylic polymer. be.

In addition, the resin layer in the technique disclosed herein is a leveling agent, a plasticizer, a softening agent, a colorant (dye, pigment, etc.), a filler (inorganic or organic), to the extent that the effect of the present invention is not significantly impaired. Needs known additives that can be used in adhesives, such as particles, foils, metal powders, etc.), antioxidants, anti-aging agents, UV absorbers, antioxidants, light stabilizers, preservatives, etc. It may be included depending on the above.

(Formation of resin layer)
As a method for providing the resin layer on the porous substrate, various conventionally known methods can be applied. For example, a method of directly applying a resin composition used for forming a resin layer to a porous substrate to form a resin layer on the porous substrate (direct method), a resin composition used for forming a resin layer. Is applied onto an appropriate peeling surface to form a resin layer on the peeling surface, and the resin layer is transferred to a porous substrate (transfer method). These methods may be used in combination.

The method for applying the resin composition is not particularly limited, and various known methods can be used. Specific examples include roll coats, kiss roll coats, gravure coats, reverse coats, roll brushes, spray coats, dip roll coats, bar coats, knife coats, air knife coats, curtain coats, lip coats, and die coaters. The law etc. can be mentioned.

The temperature at which the resin composition is dried is preferably 40 to 200 ° C, more preferably 50 to 180 ° C, and particularly preferably 70 to 170 ° C. According to the drying temperature in the above range, it is easy to obtain a resin layer having excellent adhesive properties. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.

When the monomer component is polymerized by UV irradiation to produce an acrylic polymer, the acrylic polymer can be produced from the above-mentioned monomer component and a resin layer can be formed. A material that can be contained in the resin composition, such as a cross-linking agent, can be appropriately added to the monomer component. The monomer component, which is partially polymerized in advance to form a syrup, can be subjected to UV irradiation for forming a resin layer. A high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, or the like can be used for UV irradiation.

(Characteristics of resin layer)
The thickness of the resin layer is not particularly limited and may be, for example, about 1 μm to 1000 μm or 3 μm to 500 μm. From the viewpoint of improving the adhesive force and the adhesiveness to the unevenness of the rough surface, the thickness of the resin layer is preferably 10 μm or more, more preferably 25 μm or more, still more preferably 35 μm or more. In some embodiments, the thickness of the resin layer may be, for example, 50 μm or more, 70 μm or more, or 85 μm or more. Further, from the viewpoint of avoiding insufficient cohesive force of the resin layer, the thickness of the resin layer may be, for example, 250 μm or less, 200 μm or less, or 150 μm or less.

Although not particularly limited, the gel fraction of the resin layer disclosed herein is usually preferably in the range of 20 to 95% by weight. In some embodiments, the gel fraction of the resin layer may be, for example, 22% by weight or more, 25% by weight or more, or 30% by weight or more from the viewpoint of enhancing the cohesive force and holding power of the resin layer. .. The gel fraction of the resin layer may be, for example, 85% by weight or less, 80% by weight or less, or 75% by weight or less, from the viewpoint of enhancing the adhesive force of the resin layer and the ability to follow the unevenness on the rough surface. It may be 70% by weight or less, for example, 68% by weight or less. The gel fraction can be adjusted by the composition of the monomer component constituting the acrylic polymer, the Mw of the acrylic polymer, the use of a cross-linking agent, and the like. The gel fraction of the resin layer is measured by the following method. The same method is used in the examples described later.

[Measurement of gel fraction]
_{A sample (weight Wg 1} ) of about 0.1 g collected from the resin layer _{is wrapped in a purse-like shape with a porous polytetrafluoroethylene membrane (weight Wg 2} ) having an average pore diameter of 0.2 μm, and the mouth is octopus thread (weight Wg _3). ). As the porous polytetrafluoroethylene membrane, the trade name "Nitoflon (registered trademark) NTF1122" (Nitto Denko Corporation, average pore diameter 0.2 μm, porosity 75%, thickness 85 μm) or an equivalent product thereof is used. This packet is immersed in 50 mL of ethyl acetate and held at room temperature (typically 23 ° C.) for 7 days to elute the sol component (ethyl acetate-soluble component) in the sample to the outside of the membrane. Then, the package is taken out, the ethyl acetate adhering to the outer surface is wiped off, the package is dried at 130 ° C. for 2 hours, and the weight of the package (Wg ₄ ) is measured. By substituting each value into the following equation, it is possible to calculate the gel fraction G _C of the resin layer.
Gel fraction _{G C (%) = [(} Wg 4 -Wg 2 -Wg 3) / Wg 1] × 100

In some embodiments, the storage elastic modulus G'of the resin layer ^{is preferably 5.0 × 10 4} Pa or less, ^{more preferably 4.5 × 10 4} Pa or less, 4.0 × 10 It is more preferably ^{4 Pa or less.} When the storage elastic modulus G'of the resin layer is low, the adhesion of the resin layer to the unevenness of the rough surface (following the uneven shape) tends to be high. When the adhesiveness is high, the contact area between the resin layer and the rough surface becomes large, and the adhesive strength is easily improved. From this point of view, in some embodiments, the storage elastic modulus G'of the resin layer may be 3.8 × 10 ⁴ Pa or less, and may be 3.5 × 10 ⁴ Pa or less, 3.3 × 10 ^4. It may be Pa or less, 3.0 × 10 ⁴ Pa or less, or 2.8 × 10 ⁴ Pa or less. Further, from the viewpoint of imparting an appropriate cohesive force to the resin layer to enhance the adhesive force and the holding force, the storage elastic modulus G'of the resin layer may be, for example, 1.0 × 10 ⁴ Pa or more, 1.2. × may be ¹⁰ 4 Pa or more, may be 1.5 × ¹⁰ 4 Pa or more.

The storage elastic modulus G'of the resin layer can be measured using a commercially available dynamic viscoelasticity measuring device, and more specifically, it is measured by the method described in Examples described later. The storage elastic modulus G'of the resin layer can be adjusted by the composition of the monomer component constituting the acrylic polymer, the Mw of the acrylic polymer, the use of a cross-linking agent, and the like. For example, by increasing the weight fraction of the monomer a2 in the entire monomer component or by reducing the weight ratio of the monomer a1: the monomer a2 (that is, using a larger amount of the monomer a2 with respect to the monomer a1). Therefore, the storage elasticity G'of the resin layer can be reduced. As an example of the monomer a2 having a high effect of lowering the storage elastic modulus G', the chain ether bond-containing (meth) acrylate represented by the above general formula (1) has a homopolymer Tg of −40 ° C. or lower (more than that). The temperature is preferably −45 ° C. or lower, more preferably −50 ° C. or lower, for example, −55 ° C. or lower).

<Laminated sheet>
The laminated sheet disclosed herein has any of the resin layers described above on at least one side of the porous substrate described above. Hereinafter, the exemplary structure of the laminated sheet will be described with reference to the drawings, but the structure of the laminated sheet disclosed herein is not limited by these examples.

The laminated sheet may be in the form of a single-sided pressure-sensitive adhesive sheet (that is, a single-sided adhesive pressure-sensitive adhesive sheet) in which the resin layer is a pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer is provided only on one side of the porous substrate. .. An embodiment of such a laminated sheet is schematically shown in FIG. The laminated sheet (single-sided adhesive sheet) 1 is a sheet-like porous base material (for example, a resin foam sheet) 10 having a first surface 10A and a second surface 10B, and a resin provided on the first surface 10A side thereof. A layer (adhesive layer) 21 is provided. The resin layer 21 is provided fixedly on the first surface 10A side of the base material 10, that is, without the intention of separating the resin layer 21 from the base material 10. The laminated sheet 1 is used by attaching the resin layer 21 to the adherend. As shown in FIG. 1, the laminated sheet 1 before use (that is, before being attached to the adherend) has a surface (adhesive surface) 21A of the resin layer 21 having a peeling surface at least on the side facing the resin layer 21. It may be a component of the laminated sheet 100 with a release liner in a form protected by the release liner 31. As the peeling liner 31, for example, a sheet-like base material (liner base material) having a peeling layer provided on one side thereof so that one side becomes a peeling surface can be preferably used. Alternatively, the release liner 31 is omitted, the base material 10 having the second surface 10B as the release surface is used, and the laminated sheet 1 is wound so that the adhesive surface 21A comes into contact with the second surface 10B of the base material 10. It may be in a protected form (roll form).

The structure of the laminated sheet according to another embodiment is schematically shown in FIG. The laminated sheet 2 includes a sheet-like base material (for example, a resin foam sheet) 10 having a first surface 10A and a second surface 10B, a resin layer 21 fixedly provided on the first surface 10A side thereof, and the like. A resin layer 22 fixedly provided on the second surface 10B side is provided. At least one of the resin layers 21 and 22 is any of the above-mentioned resin layers. In a preferred embodiment, both the resin layers 21 and 22 are any of the resin layers described above. In this case, the materials and thicknesses of the resin layers 21 and 22 may be the same or different. Alternatively, only one of the resin layers 21 and 22 may be one of the above-mentioned resin layers, and the other one may be another resin layer (for example, a resin layer having a composition not containing the above-mentioned acrylic polymer). .. When the other resin layer is a pressure-sensitive adhesive layer, the laminated sheet 2 of the present embodiment is configured as a double-sided pressure-sensitive adhesive sheet (that is, a double-sided adhesive pressure-sensitive adhesive sheet). The laminated sheet 2 is used by attaching the resin layer (first pressure-sensitive adhesive layer) 21 and the resin layer (second pressure-sensitive adhesive layer) 22 to different parts of the adherend. The locations where the resin layers 21 and 22 are attached may be the respective locations of the different members, or may be different locations within a single member. In the laminated sheet 2 before use, as shown in FIG. 2, the surface (first adhesive surface) 21A of the resin layer 21 and the surface (second adhesive surface) 22A of the resin layer 22 face at least the resin layers 21 and 22. It may be a component of the laminated sheet 200 with a peeling liner in a form protected by the peeling liners 31 and 32 whose respective sides are peeling surfaces. As the release liners 31 and 32, for example, those configured by providing a release layer with a release treatment agent on one side of a sheet-shaped base material (liner base material) so that one side becomes a release surface are preferably used. obtain. Alternatively, the peeling liner 32 is omitted, a peeling liner 31 having both sides as peeling surfaces is used, and the laminated sheet 2 is overlapped with the peeling liner 31 and wound in a spiral shape so that the second adhesive surface 22A becomes the peeling liner 31. An adhesive sheet with a release liner in a protected form (roll form) may be formed by abutting against the back surface of the sheet. The other resin layer may be a layer other than the pressure-sensitive adhesive layer.

The thickness of the laminated sheet disclosed herein is not particularly limited and may be, for example, 60 μm or more. From the viewpoint of improving unevenness absorption, in some embodiments, the thickness of the laminated sheet may be, for example, 100 μm or more, 150 μm or more, 250 μm or more, 400 μm or more, or 600 μm or more. In some embodiments, the thickness of the laminated sheet may be 800 μm or greater. Further, from the viewpoint of thinning and weight reduction of the laminated sheet, the thickness of the laminated sheet may be, for example, 10 mm or less, 5 mm or less, 3 mm or less, or 2 mm or less.

The tensile breaking strength Ta of the laminated sheet disclosed herein ^{is preferably 0.9 × 10 6} Pa or more. A laminated sheet having such a tensile breaking strength Ta has high durability against tensile stress. Therefore, even when combined with a resin layer (typically an adhesive layer) that strongly adheres to the adherend, the bonded state between the adherend and the laminated sheet is broken inside the laminated sheet (particularly porous). It is unlikely that it will be damaged by (destruction of the base material). This makes it possible to firmly join or fix the adherend.

In the present specification, the tensile breaking strength Ta of the laminated sheet means a value per cross-sectional area of the base material of the laminated sheet, which is obtained by using the laminated sheet as a test piece, unless otherwise specified. The tensile breaking strength Ta (unit: Pa) of the laminated sheet is the load F (unit: Pa) when the test piece is pulled at a speed of 500 mm / min according to the tensile strength measuring method specified in JIS K6767 and the test piece is broken. It is calculated by dividing N) by the cross-sectional area A (unit: m ^{2) of the base material.} The cross-sectional area A of the base material is typically obtained as the product of the width of the base material and the thickness of the base material. As the width of the base material, the value of the width of the test piece can usually be used. More specifically, the tensile breaking strength Ta of the laminated sheet can be measured by the method described in Examples described later. When the laminated sheet is long, it is desirable that the pulling direction in the above test coincides with the longitudinal direction (which may be the flow direction (MD) of the base material). Further, it is desirable that the tensile breaking strength Ta of the laminated sheet does not be extremely different between the strength measured for MD and the strength measured for TD. Here, TD means a direction orthogonal to MD. For example, the tensile breaking strength Ta for MD is preferably 0.2 to 5 times, more preferably 0.5 to 2 times, the tensile breaking strength Ta for TD. The tensile breaking strength Ta of the laminated sheet can be controlled, for example, by selecting the material of the base material constituting the laminated sheet, adjusting the degree of cross-linking, adjusting the apparent density, adjusting the size and structure of the voids, and the like.

Here, the tensile breaking strength Ta of the laminated sheet is obtained as the value of "per cross-sectional area of the base material". In the laminated sheet disclosed here, the contribution of the resin layer to the breaking load of the test piece is usually ignored. It is small enough to be possible (typically less than 1% of the value of the breaking load), and therefore, it is an object of the present application to include the cross-sectional area of the resin layer in the cross-sectional area used for calculating the tensile breaking strength Ta. This is because it is rather difficult to grasp the characteristics of the laminated sheet suitable for the above. Further, since the presence of the resin layer has an extremely small contribution to the tensile breaking strength Ta of the laminated sheet, from the viewpoint of solving the problem of the present invention, the laminated sheet is used as a sample by the above method (that is, of the laminated sheet). The tensile breaking strength Ta obtained by dividing the breaking load by the cross-sectional area of the base material and the tensile breaking strength Ts of the base material can be roughly equated. Therefore, in the technique disclosed herein, the value of the tensile breaking strength Ts of the base material can be used as an alternative value of the tensile breaking strength Ta of the laminated sheet or at least a practically sufficient approximation value. Further, Ta and Ts in the present specification can be interchanged with each other unless otherwise specified. The tensile breaking strength Ts of the base material is the same as the tensile breaking strength Ta of the laminated sheet described above, except that the base material is used as a test piece (that is, the load at break of the base material is applied to the base. (Divided by the cross-sectional area of the material).

From the viewpoint of enabling stronger bonding, the tensile breaking strength Ta of the laminated sheet is preferably 1.0 × 10 ⁶ Pa or more, more preferably 1.1 × 10 ⁶ Pa or more, and further preferably 1. It is 2 × 10 ⁶ Pa or more. The laminated sheet disclosed herein can also be preferably carried out in an embodiment in which the tensile breaking strength Ta is 1.5 × 10 ⁶ Pa or more or 1.8 × 10 ^{6 Pa or more.} The tensile breaking strength Ta of the laminated sheet is not particularly limited. From the viewpoint of facilitating compatibility with the unevenness followability of the rough surface, in some embodiments, the tensile breaking strength Ta of the laminated sheet is usually 30 × 10 ⁶ Pa or less, and 20 × 10 ⁶ Pa or less. But well, it may be a less than ¹⁰ × 10 6 Pa, may be 8.0 × ¹⁰ 6 Pa or less. The laminated sheet disclosed herein can also be suitably carried out in an embodiment in which the tensile breaking strength Ta is, for example, 6.0 × 10 ⁶ Pa or less, 5.0 × 10 ⁶ Pa or less, or 4.0 × 10 ^{6 Pa or less.} ..

In the laminated sheet disclosed herein, the relationship between the tensile breaking strength Ta (unit: Pa) of the laminated sheet and the storage elastic modulus G'(unit; Pa) of the resin layer is as follows: 10 ≦ Ta / G'. It can be preferably carried out in a manner satisfying. The value of Ta / G'tends to increase due to the flexibility of the resin layer and / or the resistance to breakage due to the tensile stress of the laminated sheet. Therefore, the laminated sheet having Ta / G'at least a predetermined value adheres well to the rough surface from an early stage, and is from the rough surface due to fracture inside the laminated sheet (particularly inside the porous substrate). It can be difficult for peeling to occur. From this point of view, Ta / G'may be, for example, 18 or more, 25 or more, 30 or more, or 40 or more. In some embodiments, Ta / G'may be 45 or greater, 50 or greater, 60 or greater, 75 or greater, or 100 or greater. The laminated sheet disclosed herein may also be suitably carried out in an embodiment in which Ta / G'is 110 or more or 125 or more. The upper limit of Ta / G'is not particularly limited, but may be, for example, 400 or less, or 300 or less in consideration of availability of materials and the like.

Although not particularly limited, the laminated sheet disclosed herein may have an initial adhesive force (gypsum board adhesive force) of 6.0 N / 20 mm or more with respect to the gypsum board. In some embodiments, the gypsum board adhesive strength is preferably 9.0 N / 20 mm or more, preferably 10.0 N / 20 mm or more, 12.5 N / 20 mm or more, and 13.0 N /. It may be 20 mm or more. The gypsum board adhesive strength is grasped by measuring the 180 ° peel strength 30 minutes after application to the gypsum board by the method described in Examples described later. In this 180 ° peel strength measurement, it is desirable that the peeling of the laminated sheet from the gypsum board proceeds without breaking the laminated sheet inside the base material.

Although not particularly limited, the laminated sheet disclosed herein may have an initial adhesive force (calcium silicate plate adhesive force) of 6.0 N / 20 mm or more with respect to the calcium silicate plate. In some embodiments, the calcium silicate plate adhesive strength is preferably 9.0 N / 20 mm or more, may be 10 N / 20 mm or more, may be 20 N / 20 mm or more, or may be 30 N / 20 mm or more. .. The adhesive strength of the calcium silicate plate is grasped by measuring the 180 ° peel strength 30 minutes after the application to the calcium silicate plate by the method described in Examples described later. In this 180 ° peel strength measurement, it is desirable that the peeling of the laminated sheet from the calcium silicate plate proceeds without breaking the laminated sheet inside the substrate. Further, in the laminated sheet disclosed herein, the adhesive strength of the gypsum board and the adhesive strength of the calcium silicate board are preferably 6.0 N / 20 mm or more, and both are 9.0 N / 20 mm or more. It is more preferable, and it is further preferable that both are 10.0 N / 20 mm or more.

Although not particularly limited, the laminated sheet disclosed herein may have an initial adhesive force (plywood adhesive force) of 6.0 N / 20 mm or more with respect to the softwood plywood. In some embodiments, the plywood adhesive strength is preferably 9.0 N / 20 mm or more, preferably 10 N / 20 mm or more, 13 N / 20 mm or more, 15 N / 20 mm or more, 18 N /. It may be 20 mm or more. The plywood adhesive strength is grasped by measuring the 180 ° peel strength 30 minutes after application to the plywood (typically softwood plywood) by the method described in Examples described later. In this 180 ° peel strength measurement, it is desirable that the peeling of the laminated sheet from the plywood proceeds without breaking the laminated sheet inside the base material.

Although not particularly limited, when the laminated sheet disclosed herein is in the form of a double-sided adhesive sheet, the laminated sheet has a shear adhesive force of 3.0 × measured by the method described in Examples described later. It can be 10 ⁵ N / m ² or more. In some embodiments, the shear adhesive force is ^{preferably 3.5 × 10 5} N / m ² or more, and may be 4.0 × 10 ⁵ N / m ² or more, 4.5 × may be a 10 ⁵ N / ^{m 2} or more, it may be 5.0 × ¹⁰ 5 N / ^{m 2} or more.

Although not particularly limited, the laminated sheet disclosed herein preferably has a deviation distance of less than 1.0 mm in a holding force test measured by the method described in Examples described later, and is 0.8 mm or less. Is more preferable. In such a laminated sheet, the resin layer has a moderately high cohesive force. According to the laminated sheet having such a resin layer on a porous base material having good unevenness absorption, an adherend having a rough surface can be firmly bonded or fixed.

<Peeling liner>
When the resin layer of the present invention is exposed, the resin layer may be protected by a release liner whose surface in contact with the resin layer is a release surface until it is put into practical use. In practical use, the release liner is removed from the resin layer. The release liner is not particularly limited, and is, for example, a release liner having a release layer on the surface of a liner base material such as a resin film or paper (paper on which a resin such as PE is laminated) or a fluoropolymer. A release liner made of a resin film formed of a low adhesive material such as (polytetrafluoroethylene, etc.) or a polyolefin resin (PE, PP, etc.) can be used. Since the surface smoothness is excellent, a release liner having a release layer on the surface of the resin film as a liner base material or a release liner made of a resin film formed of a low adhesive material can be preferably adopted. The resin film is not particularly limited as long as it can protect the resin layer, and is, for example, a PE film, a PP film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride copolymer film. , Polyester film (PET film, PBT film, etc.), polyurethane film, ethylene-vinyl acetate copolymer film and the like can be exemplified. For forming the peeling layer, for example, a silicone-based stripping agent, a long-chain alkyl-based stripping agent, an olefin-based stripping agent, a fluorine-based stripping agent, a fatty acid amide-based stripping agent, molybdenum sulfide, silica powder, or the like can be used. , A known stripping agent can be used. The use of a silicone-based stripping agent is particularly preferred. The thickness of the release layer is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm. The thickness of the release liner is not particularly limited, but is usually about 5 μm to 200 μm (for example, about 10 μm to 100 μm, preferably about 20 μm to 80 μm). The release liner may be subjected to antistatic treatment such as a coating type, a kneading type, and a thin-film deposition type, if necessary.

<Use>
The laminated sheet disclosed here takes advantage of its excellent ability to follow the unevenness of the rough surface, for example, concrete, mortar, gypsum board, wood such as coniferous plywood, cement board such as wood-based cement board, calcium silicate. It can be preferably used in a manner of being attached to an adherend having a rough surface such as a board, a tile, a brick, a foam, or the like. The arithmetic average roughness Ra of the rough surface may be, for example, about 1 μm to 800 μm. The laminated sheet can be particularly preferably used for an adherend having a rough surface having an arithmetic average roughness Ra of 1 μm to 500 μm. The arithmetic average roughness Ra of the rough surface may be, for example, about 3 μm to 300 μm, or may be about 5 to 150 μm.
Further, the laminated sheet disclosed herein is used to firmly fix a member having a large weight and / or size to a base material, such as a building material, by taking advantage of its high resistance to breakage in the laminated sheet. Can be preferably used in. The laminated sheet used for this purpose is typically in the form of a double-sided adhesive sheet, and is used in such a manner that one adhesive surface and the other adhesive surface are attached to the member and the base material, respectively. In applications where at least one of the surface of the member and the surface of the base material is the rough surface described above, the effect of applying the laminated sheet disclosed herein can be particularly well exhibited. The member having a large weight and / or size may be, for example, a concrete board, a mortar board, a gypsum board, a wood board such as a softwood plywood, a cement board such as a wood-based cement board, a calcium silicate board or the like. Further, the laminated sheet disclosed herein can be firmly adhered to a smooth adherend, and can be preferably applied to such an adherend.

The matters disclosed herein include:
(1) A laminated sheet containing a porous base material and a resin layer provided on at least one surface of the porous base material.
The porous substrate has a 25% compression hardness of 1.00 MPa or less, and has a hardness of 1.00 MPa or less.
The resin layer is
Monomer a1; C _4-14 alkyl (meth) acrylate and
Monomer a2; at least one selected from the group consisting of chain ether bond-containing (meth) acrylates and branched C _{15-20 alkyl (meth) acrylates.}
Contains an acrylic polymer, which is a polymer of monomer components containing
Here, the content of the monomer a1 in the monomer component is 50 to 97% by weight, and the content of the monomer a2 is 3 to 50% by weight.
A laminated sheet having a tensile breaking strength Ta of 0.9 × 10 ⁶ Pa or more.
(2) The laminated sheet according to (1) above, wherein the monomer component contains _{C8-14 alkyl (meth) acrylate as the monomer a1.}
(3) the monomer component comprises a _{C 8-14} branched alkyl (meth) acrylate as the _{C 8-14} alkyl (meth) acrylate, laminated sheet according to (2).
(4) The laminated sheet according to any one of (1) to (3) above, wherein the resin layer has a storage elastic modulus ^{G'at 23 ° C. of 1.0 × 10 4 to} 5.0 × 10 ^{4 Pa.} ..
(5) The resin layer is provided on both one side and the opposite side of the porous base material, and the shear adhesive force (under a 23 ° C. environment) 72 hours after application is 3.0 × 10 ⁵ N. The laminated sheet according to any one of (1) to (4) above, which is / m ^{2 or more.}
(6) The relationship between the tensile breaking strength Ta (unit: Pa, in an environment of 23 ° C.) of the laminated sheet and the storage elastic modulus G'(unit: Pa) of the resin layer is as follows: '; The laminated sheet according to any one of (1) to (5) above, which satisfies;
(7) The laminated sheet according to any one of (1) to (6) above, wherein the porous base material is a stretchable base material having an elongation at break of 120% or more and 1000% or less.
(8) The porous substrate contains at least one resin selected from the group consisting of a polyolefin resin, a polyurethane resin, a polyimide resin, a polyether resin, a polyester resin and a polyacrylic resin. The laminated sheet according to any one of (1) to (7).
(9) The above-mentioned monomer component is the same as the above-mentioned monomer a2, and the general formula (1):
CH ₂ = CR ^1- COO- (AO) _n- R ²
(In the above general formula (1), R ¹ is a hydrogen atom or a methyl group, AO is an alkyleneoxy group having 2 to 3 carbon atoms, and n is a number indicating the average number of moles of the alkyleneoxy group added. There are 1 to 8, and R ² is an aryl ring, a linear or branched alkyl group, or an alicyclic alkyl group.);
The laminated sheet according to any one of (1) to (8) above, which contains a chain ether bond-containing (meth) acrylate represented by.
(10) The above-mentioned monomer component further contains at least one functional group-containing monomer selected from the group consisting of a monomer having a hydroxyl group, a monomer having a carboxy group, and a monomer having an epoxy group (1) to (9). The laminated sheet described in any of.
(11) The laminated sheet according to any one of (1) to (10) above, wherein the Tg of the acrylic polymer is −40 ° C. or lower.
(12) The weight average molecular weight of the acrylic polymer is 35 × 10 ⁴ or more, the laminated sheet according to any one of the above (1) to (11).
(13) The laminated sheet according to any one of (1) to (12) above, wherein the resin layer contains 0.01 to 5 parts by weight of a cross-linking agent with respect to 100 parts by weight of the acrylic polymer.
(14) The laminated sheet according to (13) above, wherein the cross-linking agent contains one or both of an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent.
(15) The laminated sheet according to any one of (1) to (14) above, wherein the resin layer has a gel fraction of 20 to 95% by weight.
(16) The above-mentioned (1) to (15), wherein the resin layer has a 180 ° peel strength of 6.0 N / 20 mm or more after 30 minutes of application to the gypsum board and the calcium silicate board. Laminated sheet.

(17) The laminate according to any one of (1) to (16) above, wherein the monomer component contains a chain ether bond-containing (meth) acrylate having a homopolymer Tg of −40 ° C. or lower as the monomer a2. Sheet.
(18) The monomer component is any one of (1) to (17) _{above, wherein the monomer a2 contains a branched C 15-20} alkyl (meth) acrylate having a homopolymer Tg of −30 ° C. or higher and 20 ° C. or lower. The laminated sheet described in.
(19) The laminated sheet according to any one of (1) to (18) above, wherein the ratio of the total amount of the monomer a1 and the monomer a2 to the total amount of the monomer components is 60% by weight or more.
(20) The laminated sheet according to any one of (1) to (19) above, wherein the porous base material contains a foam layer formed of a plastic foam.
(21) The laminated sheet according to (20) above, wherein the plastic foam is a crosslinked polyolefin-based foam.
(22) The laminated sheet according to (20) or (21) above, wherein the plastic foam has an average cell diameter of 10 μm or more and 400 μm or less.
(23) The laminated sheet according to any one of (1) to (22) above, wherein the density of the porous substrate is 0.07 g / cm ³ or more and 0.5 g / cm ^{3 or less.}
(24) The laminated sheet according to any one of (1) to (23) above, wherein the thickness of the porous substrate is 200 μm or more.
(25) The laminated sheet according to any one of (1) to (24) above, wherein the thickness of the resin layer is 25 μm or more.
(26) The laminated sheet according to any one of (1) to (25) above, wherein the total thickness of the laminated sheet is 250 μm or more.
(27) The adherend having a rough surface and the laminated sheet according to any one of (1) to (26) above are included, and the resin layer described above adheres to the rough surface to form the adherend. A laminated structure in which the above laminated sheet is integrated.

Hereinafter, some examples of the present invention will be described, but the present invention is not intended to be limited to those shown in such specific examples. In addition, "part" and "%" in the following description are based on weight unless otherwise specified.

<Manufacturing of laminated sheet>
(Example 1)
80 parts of 2-ethylhexyl acrylate (2EHA), 20 parts of ethylcarbitol acrylate (CBA), 4-hydroxybutyl acrylate (4HBA) in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a cooler. 0.2 part and 1 part of acrylic acid (AA) were charged together with 0.07 part of AIBN (polymerization initiator) and 100 parts of ethyl acetate, and nitrogen gas was introduced with gentle stirring to replace with nitrogen for 1 hour. The liquid temperature in the flask was maintained at around 60 to 65 ° C., and the polymerization reaction was carried out for 13 hours to prepare an acrylic polymer solution. The acrylic polymer thus obtained had a Tg of -68.4 ° C. calculated from the monomer composition and an Mw of 85 × 10 ⁴ determined by GPC.

Next, in the acrylic polymer solution obtained above, a trimethylolpropane / 2,4-tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name: Coronate) was added as a cross-linking agent to 100 parts of the solid content of the polymer. A resin composition solution was prepared by blending 0.16 parts of L).

This resin composition solution was applied to the peeled surface of the peeling liner so that the thickness of the dried resin layer was 95 μm, and dried at 130 ° C. for 5 minutes to form a resin layer. As the peeling liner, a 38 μm PET film (diafoil MRF manufactured by Mitsubishi Plastics Co., Ltd.) having a peeling surface treated with silicone on one side was used.
The resin layer formed on the release liner was treated with a corona discharge-treated polyethylene-based foam sheet (thickness 1 mm, density 0.14 g / cm ³ , 25% compression hardness 0.130 × 10 ⁶ Pa; hereinafter, “ It was attached to one side of the base material F1). The release liner was left as it was on the resin layer and used to protect the surface (adhesive surface) of the resin layer. The obtained laminated sheet was passed once through a laminator at 85 ° C. under the conditions of a pressure of 0.3 MPa and a speed of 0.5 m / min, and then cured in an oven at 50 ° C. for 2 days to obtain the laminated sheet according to Example 1. Got

(Examples 2 to 13)
The composition of the monomer component was changed as shown in Table 1, and in Examples 10 to 13, 0.02 parts of 1,3-bis (N, N-diglycidylaminomethyl) was added to the cross-linking agent with respect to 100 parts of the solid content of the polymer. ) Cyclohexane (manufactured by Mitsubishi Gas Chemical Company, trade name: Tetrad C) was used, and the acrylic polymer solution and the resin composition solution according to each example were prepared in the same manner as in Example 1. Here, in Examples 6 and 7, the amount of ethyl acetate (polymerization solvent amount) was adjusted so that an acrylic polymer having a higher Mw than in Example 1 could be obtained. As the base material, a corona discharge-treated polyethylene-based foam sheet having the density and 25% compression hardness shown in Table 1 and having a thickness of 1 mm was used. Laminated sheets according to each example were prepared in the same manner as in Example 1 except that the resin composition solution and the base material were used. The same resin composition solution as in Example 1 was used to prepare the laminated sheets according to Examples 4 and 5.

In each of the base materials used in Examples 1 to 13, the elongation at break measured by the above-mentioned method was in the range of 120% to 1000%.

<Measurement and evaluation>
(Measurement of tensile breaking strength Ta of laminated sheet)
A test piece was prepared by cutting the laminated sheet to be measured into a size of 10 mm in width and 80 mm in length. At this time, the flow direction (MD) of the laminated sheet was set to be the length direction of the test piece. The test piece was sandwiched between chucks of a tensile tester so that the distance between chucks was 40 mm under a measurement environment of a temperature of 23 ° C. and 50% RH, and was pulled at a speed of 500 mm / min. The cross-sectional area of the material group which is calculated from the thickness and width of the substrate (unit: m ^2); Load (N units) when the test piece was broken by dividing tensile strength at break Ta (units of the laminated sheet; Pa) was calculated.

(Measurement of storage elastic modulus G'of resin layer)
The resin composition solution according to each example was applied to the peeling surface of the peeling liner and dried at 130 ° C. for 3 minutes to form a resin layer having a thickness of 95 μm, which was then laminated to prepare a laminate having a thickness of about 2 mm. bottom. A sample obtained by punching the laminate into a disk shape having a diameter of 7.9 mm was sandwiched between parallel plates, and the temperature dispersion was measured under the following conditions using a viscoelasticity test apparatus. From the result, the storage elastic modulus G'(unit: Pa) at 23 ° C. was read.
[Test conditions]
Equipment: ARES manufactured by TA Instruments
Deformation mode: Torsion measurement frequency: Constant frequency 1Hz
Temperature rise rate: 5 ° C / min Measurement temperature: Measured from -70 ° C to 100 ° C Shape: Parallel plate with a diameter of 8.0 mm Sample thickness: Approximately 2 mm (initial installation)

(Calculation of Ta / G')
Ta / G'was calculated from the values of Ta (Pa) and G'(Pa) obtained above.

(Measurement of gel fraction of resin layer)
The gel fraction of the resin layer was measured by the method described above.

(180 ° peel strength measurement)
A laminated sheet to be measured was cut into a size of 20 mm in width and about 100 mm in length to prepare a measurement sample. At this time, the MD of the laminated sheet was set to be in the length direction of the measurement sample. As an adherend, gypsum board (manufactured by Yoshino Gypsum Co., Ltd., trade name Tiger board, thickness 9.5 mm), calcium silicate board (A & A Material Co., Stained # 400, thickness 6 mm), or softwood plywood (obtained from Shimachu Homes) , 12 mm thick) was used to attach the resin layer side of the measurement sample to the adherend by reciprocating a 2 kg roller once. After allowing this to stand in an environment of 23 ° C. for 30 minutes, the peel strength (N / 20 mm) was measured under the conditions of a peeling angle of 180 ° and a peeling speed of 300 mm / min.

(Measurement of holding force)
A laminated sheet to be measured was cut into a size of 10 mm in width and 100 mm in length to prepare a measurement sample. At this time, the MD of the laminated sheet was set to be in the length direction of the measurement sample. A calcium silicate plate (A & A Material Co., Ltd., stained # 400, thickness 6 mm) was used for the adherend, and the above measurement sample was applied to the adherend, and a 2 kg roller was applied to the adherend with a pasting area of 10 mm in width and 20 mm in length. It was crimped by reciprocating once. The adherend to which the measurement sample was attached in this way was hung in an environment of 40 ° C. so that the length direction of the measurement sample was in the vertical direction, and was allowed to stand for 60 minutes. Next, a load of 500 g was applied to the free end of the measurement sample, and the sample was left in an environment of 40 ° C. for 1 hour with the load applied. For the measurement sample after being left to stand, the deviation distance from the first sticking position was measured.

(Measurement of shear adhesive force)
A laminated sheet to be measured was cut into a square of 20 mm × 20 mm to prepare a measurement sample. A gypsum board (manufactured by Yoshino Gypsum Co., Ltd., trade name Tiger board, thickness 9.5 mm) and a calcium silicate board (A & A Material Co., Ltd., stained # 400, thickness 6 mm) are overlapped with this measurement sample sandwiched between them, and the weight is 5 kg. The roller was reciprocated once and crimped. This is allowed to stand in an environment of 23 ° C. for 72 hours, and then pulled by using a universal tensile compression tester (product name "TG-1kN", manufactured by Minebea) so that the adherends are kept in parallel with each other. The peel strength per 20 mm × 20 mm was measured under the condition of a speed of 50 mm / min in an environment of 23 ° C., and the shear adhesive force (N / m ² ) was obtained from the measured value.

(Followability evaluation)
The laminated sheet to be evaluated was cut into a size of 100 mm in length × 20 mm in width to prepare a measurement sample. At this time, the MD of the laminated sheet was set to be in the length direction of the measurement sample. By preparing two slide glasses (Matsunami glass) with a thickness of 1.0 mm and laminating the second slide glass so as to cover a part of the first slide glass, the thickness of the slide glass can be increased. An adherend having a corresponding step was prepared. The measurement sample is placed on the adherend so that about half of the length is located on the second slide glass and the remaining length is located on the first slide glass across the step. Placed. At this time, one side of the second slide glass forming the step was made to be substantially orthogonal to the length direction of the measurement sample. Then, an electric laminator (manufactured by MCK) was passed once along the length direction of the measurement sample at a pressure of 0.1 MPa for laminating, and the measurement sample was pressure-bonded to the adherend. After allowing this to stand in an environment of 23 ° C. for 30 minutes, the followability (adhesion) of the laminated sheet to the step was visually confirmed. Based on the result, the followability was evaluated in the following four stages.
E: No floating of the laminated sheet was observed in the stepped portion, or the length of the floating portion was 0.5 mm or less (excellent in followability).
G: Floating of the laminated sheet was observed at the stepped portion, but the length of the floating portion of the laminated sheet was less than 1.0 mm (good followability).
P: Floating of the laminated sheet was observed in the stepped portion, and the length of the floating portion of the laminated sheet was 1.0 mm or more (poor followability).

In Table 1, 2EHA is 2-ethylhexyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., homopolymer Tg = -70 ° C);
ISTA is isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., homopolymer Tg = -18 ° C);
CBA is ethyl carbitol acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., homopolymer Tg = -67 ° C);
4HBA is 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., homopolymer Tg = −32 ° C.);
AA is acrylic acid (manufactured by Toagosei Co., Ltd., homopolymer Tg = 106 ° C);
C / L is a trimethylolpropane / 2,4-tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name Coronate L);
T / C indicates 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, trade name Tetrad C);

As shown in Table 1, the laminated sheets according to Examples 1 to 9 had a clearly higher shear adhesive force than the laminated sheets according to Examples 10 to 13. Further, the laminated sheets according to Examples 1 to 9 had a shorter deviation distance in the holding force test than the laminated sheets according to Examples 10 to 13, and showed good cohesive force. The laminated sheets according to Examples 1 to 8 were particularly excellent in cohesive force. Further, the laminated sheets according to Examples 1 to 9 showed good initial adhesiveness to various adherends having a rough surface.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

1,2 Laminated sheet 10 Porous base material 10A 1st surface 10B 2nd surface 21,22 Resin layer 21A, 22A Surface 31,32 Release liner 100,200 Laminated sheet with release liner

Claims (17)

A laminated sheet containing a porous base material and a resin layer provided on at least one surface of the porous base material.
The porous substrate has a 25% compression hardness of 0.50 MPa or less, and has a hardness of 0.50 MPa or less.
The resin layer is
Monomer a1; an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms at the end of the ester group, and
Monomer a2; selected from the group consisting of (meth) acrylate having a chain ether bond in the molecular skeleton and alkyl (meth) acrylate having a branched alkyl group having 15 to 20 carbon atoms at the end of the ester group. At least one kind of
Contains an acrylic polymer, which is a polymer of monomer components containing
Here, the content of the monomer a1 in the monomer component is 50 to 97% by weight, and the content of the monomer a2 is 3 to 50% by weight.
A laminated sheet having a tensile breaking strength Ta of 0.9 × 10 ⁶ Pa or more. The laminated sheet according to claim 1, wherein the monomer component contains, as the monomer a1, an alkyl (meth) acrylate having an alkyl group having 8 to 14 carbon atoms at the end of an ester group. The monomer component is an alkyl (meth) acrylate having an alkyl group having 8 to 14 carbon atoms at the end of the ester group, and an alkyl (meth) having a branched alkyl group having 8 to 14 carbon atoms at the end of the ester group. ) The laminated sheet according to claim 2, which comprises an acrylate. The laminated sheet according to any one of claims 1 to 3, wherein the resin layer has a storage elastic modulus ^{G'at 23 ° C. of 1.0 × 10 4 to} 5.0 × 10 ^{4 Pa.} Wherein the porous substrate wherein the one side and to either of the opposite surface thereof and the resin layer is provided, it is shear adhesive strength after joining 72 hours 3.0 × 10 5 ^{N /} m ² or more, claim The laminated sheet according to any one of 1 to 4. Claim 1 that the relationship between the tensile breaking strength Ta (unit: Pa) of the laminated sheet and the storage elastic modulus G'(unit; Pa) of the resin layer satisfies the following formula: 10≤Ta / G'; The laminated sheet according to any one of 5 to 5. The laminated sheet according to any one of claims 1 to 6, wherein the porous base material is a stretchable base material having an elongation at break of 120% or more and 1000% or less. The porous base material comprises at least one resin selected from the group consisting of a polyolefin resin, a polyurethane resin, a polyimide resin, a polyether resin, a polyester resin and a polyacrylic resin, according to claim 1. The laminated sheet according to any one of 7. The monomer component is a (meth) acrylate having a chain ether bond in the molecular skeleton as the monomer a2, and has a general formula (1):
CH ₂ = CR ^1- COO- (AO) _n- R ²
(In the general formula (1), R ¹ is a hydrogen atom or a methyl group, AO is an alkyleneoxy group having 2 to 3 carbon atoms, and n is a number indicating the average number of moles of the alkyleneoxy group added. There are 1 to 8, and R ² is an aryl ring, a linear or branched alkyl group, or an alicyclic alkyl group.);
The laminated sheet according to any one of claims 1 to 8, which comprises a monomer represented by. The monomer component further comprises at least one functional group-containing monomer selected from the group consisting of a monomer having a hydroxyl group, a monomer having a carboxy group, and a monomer having an epoxy group, according to any one of claims 1 to 9. The laminated sheet described. The laminated sheet according to any one of claims 1 to 10, wherein the glass transition temperature of the acrylic polymer is −40 ° C. or lower. The weight average molecular weight of the acrylic polymer is 35 × 10 ⁴ or more, the laminated sheet according to any one of claims 1 to 11. The laminated sheet according to any one of claims 1 to 12, wherein the resin layer contains 0.01 to 5 parts by weight of a cross-linking agent with respect to 100 parts by weight of the acrylic polymer. The laminated sheet according to claim 13, wherein the cross-linking agent contains one or both of an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent. The laminated sheet according to any one of claims 1 to 14, wherein the resin layer has a gel fraction of 20 to 95% by weight. The laminate according to any one of claims 1 to 15, wherein the resin layer has a 180 ° peel strength of 6 N / 20 mm or more after 30 minutes of application to gypsum board, calcium silicate board, and softwood plywood. Sheet. The adherend having a rough surface and the laminated sheet according to any one of claims 1 to 16 are included, and the resin layer adheres to the rough surface to allow the adherend and the laminated sheet to adhere to each other. An integrated, laminated structure.

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