WO2008016188A1

WO2008016188A1 - Tile unit, tile adhering sheet, and method of installing tiles

Info

Publication number: WO2008016188A1
Application number: PCT/JP2007/065576
Authority: WO
Inventors: Tamon Tadera; Makoto Sakakibara
Original assignee: 3M Innovative Properties Company
Priority date: 2006-08-04
Filing date: 2007-08-02
Publication date: 2008-02-07
Also published as: JP2009545686A

Abstract

A tile unit (10) is provided, comprising a tile adhering sheet (5) comprising a heat-activatable adhesive resin layer, and a plurality of tiles (7) having front surfaces, the tile adhering sheet being heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer. Also, a tile adhering sheet is provided, comprising a heat-activatable adhesive resin layer, whereby the surface of the tile adhering sheet has a surface which can partially heat-activatably adhere a tile. Furthermore, a method of installing tiles is provided, comprising the steps of coating a tile bonding mortar or adhesive on a surface where tiles are to be installed; applying the tile unit above to the surface coated with the tile boding mortar or adhesive to at least partially cure the tile bonding mortar or adhesive; and separating the tile adhering sheet from the tiles.

Description

DESCRIPTION

TILE UNIT, TILE ADHERING SHEET, AND

METHOD OF INSTALLING TILES

TECHNICAL FIELD

The present disclosure relates to a tile unit for the shipping and installation of tiles en bloc on the exterior wall or the like of structures, a tile adhering sheet for forming the tile unit, and a method of installing tiles.

BACKGROUND

In general, tiles for the installation on the exterior wall or the like of a structure such as single- family house, apartment and office building are shipped and installed in the form of tile units comprising a plurality of individual tiles. For example, the tiles for the installation on the exterior wall of a single- family house are generally shipped as tile units where the size of one unit is about 30 cm square. Kraft paper is laminated to the front faces of several individual tiles by using starch glue to form a tile unit. At the installation site, a mortar or adhesive for bonding the tile is applied to the wall and prior to its curing, the tile units connected by kraft paper are attached thereto. Before the complete curing of the adhesive, the kraft paper is wetted with water and when the starch glue is well swelled, the kraft paper is peeled off. At this time, the starch glue remaining on the tile is thoroughly washed with water or dilute hydrochloric acid.

According to such a method, several tiles can be attached en bloc at equal intervals, and the quality and working efficiency are enhanced as compared with the case of attaching the tiles one by one. In the case of the exterior wall of a high-rise building or the like, a tile-adhered unit for wall construction, called pre-cast concrete, which is previously produced in a factory, is generally installed on the wall surface. In this case, the pre-cast concrete is available from aligning previously fixed tiles in a concrete casting formwork and casting concrete.

With recent diversification of the house design, the front face design of the tile is diversified, and rough surface tiles (for example, a tile having a brick surface texture) which have been heretofore unseen, are available. In the case of a rough surface tile, the starch glue after separating the kraft paper cannot be thoroughly washed out and remains on the tile surface. If the glue is left to remain, the tile surface may be discolored or turn moldy and impairs the aesthetic appearance of the tile.

In order to solve these problems, for example, Japanese Unexamined Patent Publication (Kokai) Nos. 2006- 169785 and 2003-328536 disclose a tile unit where a plurality of tiles are connected using a pressure- sensitive adhesive tape in place of adhering a plurality of tiles to kraft paper with a starch glue. However, in such a tile unit, a spacer needs to be disposed in the joint gap between a plurality of aligned and arranged tiles so as to prevent the pressure-sensitive adhesive tape from adhering to the tile side face. Also, the pressure-sensitive adhesive tape is difficult to adhere in close contact to the entire tile surface, though the pressure-sensitive adhesive thereof has some conformability to recesses and projections of the rough surface tile. Furthermore, when the pressure-sensitive adhesive tape is made to adhere by the complete contact with recesses and projections of the tile, adhesive residue tends to remain after the separation.

On the other hand, as for the installation of rough surface tiles, there has been proposed a method of connecting tiles at rear faces with a resin and fixing the tiles together with the resin in the joint part at the installation (see, Kokai No. 2002-106148) . However, this method requires exclusive apparatus and incurs a high installation cost.

SUMMARY

The present disclosure provides a tile unit which comprises a tile adhering sheet comprising a heat- activatable adhesive resin layer, and a plurality of tiles having front faces, the tile adhering sheet being heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer.

In another aspect, the present disclosure provides a tile adhering sheet comprising a heat-activatable adhesive resin layer, whereby the tile adhering sheet has a surface which can partially heat-activatably adhere a tile .

In still another aspect, the present disclosure provides a method of installing tiles comprising: coating a tile bonding mortar or adhesive on a surface where tiles are to be installed; applying the tile unit to said surface coated with the tile bonding mortar or adhesive to at least partially cure the tile bonding mortar or adhesive; and separating the tile adhering sheet from the tiles.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view showing one example of the tile unit of the present disclosure. Fig. 2 is a perspective view showing an example of the tile adhering sheet of the present disclosure, in which a heat-activatable adhesive resin layer having openings is formed on a substrate.

Fig. 3 is a cross-sectional view showing an example of the tile adhering_v sheet of the present disclosure, in which a patterned surface topography having recesses and projections is provided to the tile adhering surface of the heat-activatable adhesive resin layer.

Fig. 4 is a plan view showing an example of the tile adhering sheet of the present disclosure, in which the heat-activatable adhesive resin layer is formed by pattern-coating a heat-activatable adhesive resin on the substrate.

Fig. 5 is plan view showing an example of the tile adhering sheet of the present disclosure, in which the heat-activatable adhesive resin layer is formed by part- coating a heat-activatable adhesive resin on the substrate .

Fig. 6 is a cross-sectional view showing an example of the tile adhering sheet of the present disclosure, in which the substrate is embossed and the heat-activatable adhesive resin layer is provided in the recessed parts.

Fig. 7A and 7B are a plan view and a perspective view, showing another example of the tile adhering sheet of the present disclosure, which further comprises a film having at least partial openings and being laminated on the tile adhering surface of the heat-activatable adhesive resin layer, respectively.

Fig. 8A and 8B are a plan view and a perspective view, showing the tile adhering sheet of the present disclosure in another embodiment, which further comprises a film having at least partial openings and being laminated on the tile adhering surface of the heat- activatable adhesive resin layer, respectively.

Fig. 9 is a plan view showing an example of the tile adhering sheet of the present disclosure, in which a coating for decreasing the adhesion force is at least partially applied onto the tile adhering surface of the heat-activatable adhesive resin layer.

Fig. 10 is a schematic view showing an example of the production apparatus of the tile unit. Fig. 11 is a cross-sectional view showing the tiles and tile unit during installation in an example of the method of installing tiles using the tile unit of the present disclosure.

Fig. 12 is a photograph taken for confirming the adhering area before water spraying in the tile adhering sheet having, on the tile adhering surface of the heat- activatable adhesive resin layer, a sheet obtained by orthogonally stacking high-density polyethylene drawn tape yarns into a grid.

Fig. 13 is a photograph taken for confirming the adhering area after water spraying in the tile adhering sheet having, on the tile adhering surface of the heat- activatable adhesive resin layer, a sheet obtained by orthogonally stacking high-density polyethylene drawn tape yarns into a grid.

Fig. 14 is a photograph taken for confirming the adhering area before water spraying in the tile adhering sheet where the tile adhering surface of the heat- activatable adhesive resin layer is uncovered.

Fig. 15 is a photograph taken for confirming the adhering area after water spraying in the tile adhering sheet where the tile adhering surface of the heat- activatable adhesive resin layer is uncovered.

DETAILED DESCRIPTION Definition The term "heat-activatable adhesion (heat- activatable adhesive, heat-activatably adherable) " as used in the present disclosure means that the resin does not exhibit tack property (adhesive property) at ambient temperature, but can achieve the adhesion by contacting with an adherend (tile) in a state of being heated and activated, and again loses the tack property (adhesive property) after cooling, though the adhesion which has already been effected by the heat-activatable adhesion is maintained. The heat-activatable adhesive property can be achieved by a thermoplastic resin, a thermosetting resin or a mixture thereof. In the present disclosure, a resin having heat-activatable adhesive property is referred to as a heat-activatable adhesive resin. Representatively, when a thermoplastic resin sheet or layer is used and at least the surface of the thermoplastic resin sheet or layer is heated to near the melting point, the resin comes to exhibit tack property and can be put into close contact (pressure-adhered) with an adherend (tile) . After cooling, the sheet adheres to the tile but the sheet returned to ambient temperature does not exhibit tack property any more. In this case, as long as the basic shape of the tile adhering sheet is maintained, the heat-activatable adhesive resin comprising a thermoplastic resin or the like is preferably a resin which is not melted but is softened under heating and thereby exhibits the tack property. However, the heat-activatable adhesive resin may be partially or entirely melted, provided that the basic shape of the tile adhering sheet is maintained.

The phrase "the tile adhering sheet comprising a heat-activatable adhesive resin layer" means that the tile adhering sheet may consist of only a heat- activatable adhesive resin layer or may be a tile adhering sheet in which a heat-activatable adhesive resin layer is formed on a substrate. Also, in the present disclosure, a non-adhesive material layer or an adhesion- decreasing material layer can be partially formed on the surface of the heat-activatable adhesive resin layer with or without a substrate. In the case where the tile adhering sheet is composed of only a heat-activatable adhesive resin layer, the heat-activatable adhesive resin layer may also be referred to as a heat-activatable adhesive resin sheet.

According to the present disclosure, there is provided a tile unit comprising a tile adhering sheet comprising a heat-activatable adhesive resin layer, and a plurality of tiles having front faces, wherein the tile adhering sheet is heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer .

Fig. 1 shows one example of the tile unit 10 of the present disclosure. In the tile unit 10, a plurality of tiles 1 are adhered to the tile adhering sheet 5 comprising a heat-activatable adhesive resin layer and are arranged such that the front faces of the tiles come into contact with the sheet. In Fig. 1, the top face of the tiles 1 is a rear face, that is, a face bonded to a surface where tiles are to be installed (hereafter referred to as a tile installation surface) , for example, the outer surface of a building structure.

According to this tile unit, a sheet comprising a heat-activatable adhesive resin layer is used as the tile adhering sheet in place of a conventional sheet comprising kraft paper and starch glue, and the heat- activatable adhesive resin of the heat-activatable adhesive resin layer is softened upon thermal activation by heating to allow the tile adhering surface to closely- contact with and adhere to recesses and projections on the rough surface of the tile, so that sufficiently high adhesive strength can be maintained. Also, the heat- activatable adhesive resin has a high self-cohesive force at ambient temperature as compared with a pressure- sensitive adhesive, so that the heat-activatable adhesive resin layer can be separated from the tile surface with less resin residue remaining thereon, and can be clearly removed merely by peeling off the sheet after the installation.

The heat-activatable adhesive resin layer has no tack property at ambient temperature (for example, about 25°C) as described above. Accordingly, this enables to prevent the heat-activatable adhesive resin layer in the joint gap between tiles from adhering to the tile side face or bonding glue faces with each other to narrow the joint gap, or to prevent attachment of contamination such as dust during storage, transportation or installation. The sheet comprising a heat-activatable adhesive resin layer can have sufficiently high strength as compared with a sheet composed of kraft paper and starch glue and therefore, is assured of easy handling while enabling to maintain the tile intervals at the installation. Furthermore, this sheet has water resistance and is not ruptured even when exposed to water such as rain or is prevented from swelling due to absorption of water or from shrinking on drying, so that excellent dimensional stability can be ensured. By using a tile unit comprising the sheet comprising a heat-activatable adhesive resin layer adhered to tiles, heavy tiles or tiles with a small joining area such as staggered joint can also be arranged, or larger units used, for example, in the production of a pre-cast concrete can also be installed en bloc.

The tile may be any tile which is installed on a surface such as wall surface. The surface topography of the tile, the kind of the glaze, and the like may be variously selected depending on the intended use. The tile adhering sheet for use in the tile unit described above comprises a heat-activatable adhesive resin layer.

As defined above, the tile adhering sheet may be composed of only a heat-activatable adhesive resin layer or may be a tile adhering sheet where a heat-activatable adhesive resin layer is formed on a substrate. Also, the tile adhering sheet may have a non-adhesive material layer or an adhesion-decreasing material layer at least partially on the surface of the heat-activatable adhesive resin layer.

In some embodiments, the elongation of the tile adhering sheet, with or without a substrate, is preferably about 1% or less at the time of adhesion or transportation of the tiles. Considering the temperature which elevates at the time of adhesion or transportation of the tiles, in some embodiments, the elongation of the sheet in one dimension at 60°C or 80°C is preferably about 1% or less based on the length of the sheet in the same dimension at ambient temperature (for example, 25⁰C) . If this elongation of the tile adhering sheet is too large, the tile adhering sheet is deformed before installation and the tiles may be misaligned.

In some embodiments, the tensile stress of the tile adhering sheet at a yield point or a rupture point is preferably from about 10 to about 25 N/10 mm in view of handling property at the time of adhesion, transportation or installation of the tiles as well as flexibility and conformability of the sheet when adhered to tiles .

In some embodiments, the tile adhering sheet may be transparent or translucent, and this is advantageous in that the tile position can be viewed through the sheet during tile installation as compared with the conventional tile adhering sheet using kraft paper and starch glue.

By virtue of using a sheet comprising a heat- activatable adhesive resin layer for adhering tiles, not only can the adhesive strength be maintained resulting from the heat-activatable adhesive resin coming into close contact with the rough surface of the tile when thermally activated under heating, but also the sheet can be easily peeled off after installation. In some embodiments, unlike the case of using a pressure- sensitive adhesive, the tile side face does not adhere to the joint gap portion, the glue faces do not adhere to each other to narrow the joint gap, and/or littel or no contamination attaches during storage, transportation or installation. In addition, in some embodiments, the sheet has sufficiently high strength and therefore, is assured of easy handling while enabling one to maintain the tile intervals at the installation. Furthermore, in some embodiments, this sheet has water resistance and is not ruptured even when exposed to water such as rain or is prevented from swelling due to absorption of water or from shrinking on drying, so that excellent dimensional stability can be ensured.

The dimension of the tile adhering sheet may be variously selected depending on the shape and size of the tile, the installation surface, the installation method and the like and is not limited. In some embodiments, the tile adhering sheet may have, for example, a rectangular or square shape with the sides each being from about 100 mm to about 500 mm, preferably from about 150 mm to about 350 mm, more preferably from about 200 mm to about 300 mm.

The heat-activatable adhesive resin layer can be formed using a heat-activatable adhesive resin. As described above, the heat-activatable adhesive resin may be sufficient if it exhibits the tack property (adhesive property) when heated, and maintains the adhesion level obtained but does not exhibit tack property (adhesive property) after cooling.

As for the heat-activatable adhesive resin, typically, a thermoplastic resin can be used, but a thermosetting resin or a blend of a thermoplastic resin and a thermosetting resin having the above-described properties may also be used.

The resin usable as the heat-activatable adhesive resin includes known materials used for a so-called hot- melt adhesive. The resin may typically be used in a softened state in order to effect adhesion as a heat- activatable adhesive resin, while the hot-melt adhesive is generally used by melting it. However, the materials used for the hot-melt adhesive can be used as the material of the heat-activatable adhesive resin. In this case, the hot-melt adhesive material (heat-activatable adhesive resin) preferably exhibits substantially no tack property at room temperature (for example, at 25°C) so as not to cause adhesion to the tile side face or attachment of contamination. In some embodiments, the heat activatable adhesive resin useful in the present disclosure generally comprises, for example, a thermoplastic resin (base polymer) as the main component and, if desired, a wax and other components.

Representative examples of the thermoplastic resin which is used for the hot-melt adhesive and is also useful for the heat-activatable adhesive resin include an olefin-vinyl acetate copolymer, an olefin- (meth) acrylic acid copolymer, an olefin- (meth) acrylic acid ester copolymer, a polyolefin, a polyamide, a polyester and a polylactic acid. These resins can be suitably used as the heat-activatable adhesive resin of the present disclosure .

A copolymer of an olefin monomer such as ethylene and a comonomer such as a (meth) acrylic acid (or an ester thereof) or a vinyl acetate (VA) is useful as the heat- activatable adhesive resin. Examples of such copolymers include an ethylene-vinyl acetate (EVA) copolymer, an ethylene- (meth) acrylic acid copolymer, and an ethylene- (meth) acrylic acid ester copolymer.

In the present disclosure, a copolymer of an ethylene and a (meth) acrylic acid (or an ester thereof) is preferably used as the base polymer in the heat- activatable adhesive resin of the present disclosure. Examples of such copolymers include an ethylene-ethyl acrylate (EEA) copolymer, an ethylene-methyl methacrylate (EMMA) copolymer, and an ethylene-acrylic acid (EAA) copolymer. Among these, an ethylene-ethyl acrylate (EEA) copolymer is preferred because of its excellent flexibility at the temperatures typically encountered during transportation. Specific examples of the ethylene-acrylic acid copolymer include ZAIKTHENE (trade name) available from Sumitomo Seika Chemicals Co., Ltd., REXPEARL EAA (trade name) available from Japan Polyethylene Corp., EVAFLEX- EEA (trade name) available from Du Pont-Mitsui Polychemicals Co., Ltd., and REXPEARL EEA (trade name) available from Japan Polyethylene Corp.; and specific examples of the ethylene-methacrylic acid copolymer include NUCREL (trade name) available from Du Pont-Mitsui Polychemicals Co., Ltd. The ratio of the olefin monomer to the comonomer may be varied depending on the required adhesion force, the temperature at the adhering process (that is, adhesion temperature at the production of the tile unit) , the estimated maximum peak temperature during transportation, and the like. For example, in the case of EEA copolymer, the weight percent of EA (EA %) based on the entire copolymer is from about 10 to about 50 wt%, preferably from about 15 to about 40 wt%, more preferably from about 20 to 35 wt%.

A polyolefin-based material is also useful as the heat-activatable adhesive resin. Examples of the thermoplastic polyolefin or thermoplastic olefin-based elastomer which can be used as the base polymer of the heat-activatable adhesive resin include amorphous polyolefin, amorphous poly-α-olefin (e.g., propylene homopolymer, ethylene-propylene copolymer, and 1-butene- propylene copolymer) , ethylene-propylene copolymer (EPM) , and ethylene-propylene-diene (EPDM) copolymer. Those obtained by partially grafting a functional group to such polymers are also usable. A mixture of two or more kinds of thermoplastic polyolefins or thermoplastic olefin- based elastomers may also be used as the base polymer. Specific examples of the thermoplastic polyolefin or thermoplastic olefin-based elastomer include EASTOFLEX (amorphous polyolefin-based) available from Eastman Chemical Company, UBETAC (amorphous poly-α-olefin-based) available from Ube Industries, Ltd., BESTPLAST (amorphous poly-α-olefin-based) available from Huels AG, THERMORUN (EPM/EPDM-based) available from Mitsubishi Chemical Corp., IDEMITSU TPO (EPM/EPDM-based) available from Idemitsu Petrochemical Co., Ltd., and ADMER (modified polyolefin-based) available from Mitsui Chemicals, Inc. In addition to the thermoplastic resin as the base polymer, the heat-activatable adhesive resin may contain a wax which is not only effective for decreasing the melt viscosity of the adhesive and enhancing its coatability but also effective for adjusting other physical properties (e.g., hardness, softening point, and hot tack) of the adhesive.

As for the wax, generally any known waxes usable in the hot-melt adhesive can be used. Examples of the usable wax include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, microcrystalline wax and paraffin wax. Among these, Fischer-Tropsch wax is preferred because this wax has good compatibility with the thermoplastic polyolefin or thermoplastic olefin-based elastomer and makes it easy to adjust the melt viscosity of the adhesive. Representative examples of the Fischer-Tropsch wax include SASOL H Series available from SASOL Ltd. A mixture of two or more kinds of waxes may also be used.

The heat-activatable adhesive resin may contain the wax, for example, in an amount of 0 to about 40 wt%. If the wax content exceeds about 40 wt%, the intrinsic adhesive property of the heat-activatable adhesive resin (e.g. hot-melt adhesive composition) may be impaired. In the present disclosure, the heat-activatable adhesive resin may contain additives such as antioxidant, stabilizer, plasticizer, filler, thermoplastic resin and thermoplastic elastomer. Generally, the amounts of these and other optional additives are selected to achieve their desired effect, to the extent of not causing practical impairment of the adhesive 's end-use performance.

The heat-activatable adhesive resin may be a thermosetting resin or a blend of a thermoplastic resin and a thermosetting resin. Examples of such thermosetting resins include those generally called a B- stage adhesive which, in a partially-cured state, lacks adhesive property at ambient temperature, melted to exhibit flowability at a certain higher temperature and cured by subjecting to that temperature or more for a certain time. This adhesive may contain a curing agent such as glycidyl ether of bisphenol A, an alicyclic epoxy compound, an epoxy resin (e.g., novolak-type epoxy resin, urethane-modified epoxy resin) , imidazole derivatives and alkylurea derivatives. The adhesive may also contain a curing accelerator and/or filler, if desired. Also, in this adhesive, a thermoplastic resin such as (meth) acrylic acid ester-containing copolymer may be further blended. If desired, a release layer (e.g., release paper, release film) may be provided on the tile adhering surface of the heat-activatable adhesive resin layer, and the adhesive sheet may be used by removing the release layer at the production of the tile unit. The heat-activatable adhesive resin generally has no tack property (adhesive property) at ambient temperature but exhibit the tack property (adhesive property) when heated and softened, that is, the softening temperature of the resin must be higher than ambient temperature. Furthermore, the resin preferably has a high softening temperature and a high melting point in consideration of the temperature which may elevate during storage, transportation or installation, so that the tile adhering sheet after adhering to tiles can be prevented from exhibiting the tack property during storage or transportation and causing adhesion to the tile side surface or attachment of contamination or that the tile adhering sheet can be kept adhered to the tiles during storage or transportation. Accordingly, in some embodiments, although not limited, the melting point of the heat-activatable adhesive resin as measured according to JIS K7121 (1987) is preferably about 6O⁰C or more, more preferably about 8O⁰C or more. On the other hand, in some embodiments, the melting point is preferably about 150⁰C or less, more preferably about 110⁰C or less. As the melting point is higher, the resin is more stable against fluctuation of the temperature in the storage environment, but an excessively high melting point is not necessary and unprofitably decreases the workability in adhesion of tiles. The thickness of the heat-activatable adhesive resin layer is not particularly limited. However, when a substrate is not used, for ensuring sufficiently high strength of the tile unit and maintaining good handling property, the thickness of the heat-activatable adhesive resin layer is, although not limited to, usually from about 50 μm to about 5 mm. In the case where a substrate is used, the thickness of the heat-activatable adhesive resin layer is sufficient if it is a thickness enough to enable conforming to recesses and projections of the tile surface, and although not limited, the thickness may be, for example, from about 10 μm to about 1 mm, preferably from about 20 to about 100 μm.

In the case where the heat-activatable adhesive resin layer has sufficiently high strength by itself or the weight of the tile is small, a substrate is not necessary and the heat-activatable adhesive resin layer in the form of a self-supporting sheet may hold a plurality of tiles .

However, in some embodiments, the strength of the tile adhering sheet is required or desired to be enhanced, and therefore the heat-activatable adhesive resin layer is preferably supported on a substrate. Also, when the heat-activatable adhesive resin layer is discontinuous, the heat-activatable adhesive resin layer sometimes needs to be supported on a substrate.

As for the substrate, in some embodiments, an appropriate plastic sheet is used, including a polyolefin-based polymer sheet such as polyethylene, polypropylene or a copolymer or blend thereof, a polyester sheet such as polyethylene terephthalate, and a polyamide sheet. Among these, a high-density polyethylene is preferred and the strength thereof may be more enhanced by mixing a filler such as CaCC>3 or talc.

In order to suppress the elongation of the tile adhering sheet to about 1% or less during the adhesion and transportation of the tiles, the elongation of the substrate for the tile adhering sheet is preferably about 1% or less at the adhesion and transportation of the tiles. More specifically, considering the maximum temperature at the adhesion and transportation of the tiles, the elongation of the tile adhering sheet in one dimension at 60°C and further at 80°C is preferably 1% or less based on the length of the sheet in the same dimension at ambient temperature (for example, 25°C) .

The tensile stress of the substrate at a yield point or a rupture point is, although not limited, preferably from 5 to 40 N/10 mm, more preferably from about 10 to about 25 N/10 mm, at ambient temperature (25⁰C) .

For ensuring the strength high enough to hold the tiles at predetermined intervals and at the same time, maintaining the flexibility to obtain good workability, in some embodiments, the thickness of the substrate is usually from about 20 μm to about 5 mm, preferably from about 30 to about 150 μm.

The shape and dimension of the substrate help define the shape and dimension of the tile adhering sheet and therefore, as described above, in some embodiments, the substrate may have a rectangular or square shape with the sides each being from about 100 to about 500 mm, preferably from about 150 to about 350 mm, more preferably from about 200 to about 300 mm.

The method for forming the heat-activatable adhesive resin layer on the substrate is not particularly limited. The substrate and the heat-activatable adhesive resin layer may be separately formed and then laminated together, the heat-activatable adhesive resin layer may be formed on the substrate by a method such as extrusion molding or coating, or the substrate and the heat- activatable adhesive resin layer may be formed by a two- layer coextrusion method. In the case where the heat- activatable adhesive resin layer is composed of a thermoplastic resin, melt extrusion is easy and simple.

The method of forming a tile unit using a tile adhering sheet comprising a heat-activatable adhesive resin layer with or without a substrate, and the method of installing tiles are described later. Generally, the tiles having various surface topographies and formed by using various materials (e.g., glaze) are available. Therefore, the degree of easiness that the tile and the tile adhering sheet are adhered together may differ depending on each tile. Accordingly, even when a tile adhering sheet having the same heat- activatable adhesive resin layer is used, the force necessary for separating the tile adhering sheet after tile installation may differ depending on the kind of the tile. The tile adhering sheet is separated before the material (e.g., adhesive) for fixing the tiles to a building is completely cured, and therefore, if the release force is excessively large, the installed tiles may be detached from the adhesive coated on the installation surface and this sometimes leads to an installation failure. If the thickness of the tile adhering sheet is changed in order to control the adhesion force, a good balance between the adhesion force and the release force can be difficult to be achieved, when using a tile having a surface material easy to be adhered and having large recesses and protrusions on the surface .

According to some preferred embodiments of the present disclosure, the adhesion force of the tile adhering sheet can be variously adjusted, depending on the surface topography or outermost surface material

(e.g., glaze, surface coating) of the tile used and/or the method of installing tiles. More specifically, the adhering area of the heat-activatable adhesive resin layer to the tile surface is varied depending on the kind of the tile and/or the method of installing tiles. When the sheet release force of the entire tile unit is adjusted by varying the adhering area of the heat- activatable adhesive resin layer in the tile adhering sheet and the relationship of (sheet release force) < (adhesion force for fixing the tiles to the outer surface of a building) is thereby established, misalignment and detachment of tiles at the installation can be prevented. For the purpose of the present application, the sheet release force corresponds to the force necessary for separating the tile adhering sheet from the front face of the tile (that is, the adhered surface to sheet) and in the present disclosure, essentially indicates the force required for the interface separation between the heat- activatable adhesive resin layer of the tile adhering sheet and the front face of the tile. The adhesion force for fixing the tiles to the outer surface of a building corresponds to the adhesion force between the rear face of the tile and the tile installation surface (e.g., outer surface of a building) , and indicates a smallest force out of forces required for the interface separation between the tile and the adhesive for tile installation, the cohesive failure inside the adhesive for tile installation, and the interface separation between the adhesive for tile installation and the tile installation surface. It should be noted that, in general, the adhesive between the tile and the outer surface of a building is not completely cured. The adhesion force between the tile and the tile installation surface is, in some cases, as low as only about 50 gf/cm (49 N/m) , because the adhesive between the tile and the tile installation surface is generally not in a completely cured state so as to allow for positional correction of the tiles. Even in the case of such a low adhesion force between the tile and the tile installation surface, it is desirable that the tile is prevented from misalignment or detachment at the time of separating the tile adhering sheet.

The adhesion force of the tile adhering sheet can be easily adjusted according to various use modes by- adjusting the adhering area of the heat-activatable adhesive resin layer of the sheet, thereby allowing for preventing troubles such as misalignment of tiles or detachment of tiles from occurring when the tile adhering sheet is peeled off after the installation of such tiles, while the tiles having various surface topographies or outermost surface materials are satisfactorily held in place during transportation.

As described above, the tile adhering sheet of the present disclosure is characterized in that the sheet relatively strongly adheres to tiles and maintains the tile unit when transporting the unit, and that at the separation from the tiles, by virtue of high cohesive force of the resin as compared with the pressure- sensitive adhesive, the heat-activatable adhesive resin layer less causes a cohesive failure at ambient temperature and allows no partial remaining of the resin on the tile surface. This provides the tile adhering sheet of the present disclosure with excellent property as an adhesive sheet for forming a tile unit and installing the tiles. In the present disclosure, the separation force from tiles of the tile adhering sheet depends on, for example, the kind of the tile or the kind of the adhesive for attaching the tiles to a wall surface and cannot be limited but is preferably adjusted to, for example, from about 20 to 150 gf/cm (20 to 147 N/m) at 180° peeling.

In a certain embodiment, the adjustment of the adhering area between the heat-activatable adhesive resin layer in the tile adhering sheet and the tile can be achieved by using a tile adhering sheet containing a heat-activatable adhesive resin layer having a surface which partially heat-activatably adheres to the tile. For example, the adjustment can be achieved by imparting a patterned surface topography having recesses and projections to the surface of the heat-activatable adhesive resin layer, only partially forming the heat- activatable adhesive resin layer on the substrate surface, or partially covering the heat-activatable adhesive resin layer formed in the sheet with a non- adhesive material or adhesion-decreasing material layer so that the heat-activatable adhesive resin layer is partially exposed, though the present disclosure is not limited thereto. These methods are described specifically below.

In one method, the adjustment of the adhering area in the heat-activatable adhesive resin layer of the tile adhering sheet can be achieved by changing the shape of the heat-activatable adhesive resin layer itself.

For example, in the case where the tile adhering sheet comprises only a heat-activatable adhesive resin layer, as well as where the tile adhering sheet has a heat-activatable adhesive resin layer on a substrate, the adhering area can be adjusted by a method such as forming a heat-activatable adhesive resin layer with openings or forming a patterned surface topography having recesses and projections on the surface of the heat-activatable adhesive resin layer.

Fig. 2 shows an example of the heat-activatable adhesive resin layer having openings. Openings 9 are formed in the heat-activatable adhesive resin layer 4. In the tile adhering sheet shown in Fig. 2, the heat- activatable adhesive resin layer 4 is formed on a substrate 8, but the substrate may not be necessary. Also, the openings may penetrate from the heat- activatable adhesive resin layer 4 to the substrate 8. In order to form openings in the sheet-like heat- activatable adhesive resin layer, for example, the sheet- like heat-activatable adhesive layer is punched into a certain shape by a punching blade, or a certain shape is cut and removed by using a cutter, a laser or the like, whereby a heat-activatable adhesive resin layer with partial openings can be produced. If possible, openings may be previously formed at the formation of the sheet- like heat-activatable adhesive resin layer.

The sheet-like heat-activatable adhesive resin layer having openings formed therein may be used as the tile adhering sheet without change or after laminating on a substrate.

The shape and dimension of the openings are not particularly limited and may be determined depending on the adhesion force of the heat-activatable adhesive resin layer, the kind of the tile, or the like, but the openings may have, for example, a circular, elliptical, triangular, rectangular or square shape.

The opening ratio of the heat-activatable adhesive resin layer with openings may be, depending on the intended use, from about 20 to about 90%, preferably from about 30 to about 80%, based on the area of the entire adhering surface of the tile adhering sheet. By selecting the appropriate opening ratio in this range, misalignment, detachment or the like of tiles during transportation can be prevented and at the same time, an optimal sheet release force can be obtained when separating this tile adhering sheet after tile installation.

Also, the surface of the heat-activatable adhesive resin layer may be formed to have a patterned surface topography having recesses and projections to allow only the peak surface of the projected parts to contact with the tile and exhibit the heat-activatable adhesive property. For example, Fig. 3 shows a cross-sectional view of a tile adhering sheet 5 where the heat- activatable adhesive resin layer 4 formed on a substrate 8 has a patterned surface topography having recesses and projections on the tile adhering surface. In Fig. 3, the tile adhering sheet has a substrate, but the substrate may not be necessary. By virtue of such a patterned surface topography on the tile adhering surface, only the projected area and its neighborhood work out to the substantial adhering portion and therefore, the adhering area between the heat-activatable adhesive resin layer and the tile surface can be adjusted.

The patterned surface topography having recesses and projections, imparted to the tile adhering surface of the heat-activatable adhesive resin layer, may have arbitrary shape and dimension, and examples thereof include a truncated cone, a truncated pyramid, a rectangular parallelepiped, a cylindrical column and a semispherical form, and such a shape may be reversed to form recessed parts (in this case, the portions other than the portions where such a shape is provided work out to the projected parts) . The arrangement of recesses and projections may be regular or irregular. The shape, dimension and arrangement of this patterned surface topography may be selected depending on the kind of the tile, the melting properties of the heat-activatable adhesive resin and the production conditions of the tile sheet, such that the adhering area effective for the adhesion of tiles becomes from about 20 to about 90%, preferably from about 30 to about 80%, based on the entire area of the tile adhering sheet. The depth of the recessed parts is, depending on the desired adhesion force of the heat-activatable adhesive resin layer, preferably from about 10 μm to about 1 mm, more preferably from about 20 to about 100 μm.

The patterned surface topography having recesses and projections can be imparted to the tile adhering surface of the heat-activatable adhesive resin layer, by heating the heat-activatable adhesive resin to near its melting point or more and pressing a stamping die having a desired topography or by performing an embossing process known in the art. In the case where the tile adhering sheet has the heat-activatable adhesive resin layer on a substrate, as described above, the heat-activatable adhesive resin layer (in the form of a film or a sheet) having openings or a patterned surface topography may be laminated on a substrate and used as the tile adhering sheet. Alternatively, at the formation of the heat-activatable adhesive resin layer on the substrate, the heat- activatable adhesive resin layer may be partially formed on the substrate or formed to have a patterned surface topography thereon, or after forming the heat-activatable adhesive resin layer on the substrate, a part of the heat-activatable adhesive resin layer may be removed.

In order to form the heat-activatable adhesive resin layer partially on a substrate, a method such as pattern- coating and part-coating may be utilized. The pattern- coating means that the heat-activatable adhesive resin layer is coated in a predetermined pattern such as dot or grid, and the part-coating means that the heat- activatable adhesive resin layer is partially coated in a stripe manner. For example, Figs. 4 and 5 are plan views showing the tile adhering sheet 5 where the heat- activatable adhesive resin layer 4 is pattern-coated and part-coated, respectively, on a substrate 8. In the pattern coating or part coating, the pattern shape, stripe shape, arrangement, interval and the like may be variously selected depending on the intended use. The area of the pattern-coated or part-coated heat- activatable adhesive resin layer is from about 20 to about 90%, preferably from about 30 to about 80%, based on the entire area of the tile adhering sheet. This tile adhering sheet contains a substrate and therefore, the heat-activatable adhesive resin layer may be continuous or discontinuous. The pattern-coating or part-coating may be performed by selecting the die shape on the heat-activatable adhesive resin layer side to give a desired pattern or stripe and laminating the heat-activatable adhesive resin layer on the substrate by two-layer extrusion or coextruding these layers through the die.

Also, as described above, a patterned surface topography having recesses and projections may be imparted to the tile adhering surface of the heat- activatable adhesive resin layer formed on the substrate or the heat-activatable adhesive resin layer may be embossed. Furthermore, an embossed sheet having a patterned topography-imparted surface may be used as the substrate and the heat-activatable adhesive resin layer may be coated thereon, such that the projected parts of the embossed substrate are used as the non-adhesive part by forming the heat-activatable adhesive layer only in the recessed parts of the embossed substrate or the projected parts of the embossed substrate are used as the substantially non-adhesive part due to in-plane difference in the thickness of the heat-activatable adhesive resin layer. For example, Fig. 6 shows a cross- sectional view of the tile adhering sheet 5 where the heat-activatable adhesive resin layer 4 is formed only in the recessed parts of the embossed substrate 8.

The patterned surface topography of the embossed sheet used as the substrate of this tile adhering sheet may have arbitrary shape and dimension, and examples thereof include a truncated cone, a truncated pyramid, a rectangular parallelepiped, a cylindrical column and a semispherical form. Also, the arrangement of recesses and projections may be regular or irregular. In this embodiment of the present disclosure, a heat-activatable adhesive resin layer is formed substantially in the recessed parts of the patterned surface topography thereby forming the tile adhering surface of the tile adhering sheet. The total area of the recessed parts of the patterned surface topography in the surface where the heat-activatable adhesive resin layer is formed is from about 20 to about 90%, preferably from about 30 to about 80%, based on the entire area of the tile adhering sheet. The depth of the recessed parts is, depending on the thickness of the substrate and the desired adhesion force of the heat-activatable adhesive resin layer, preferably from about 10 μm to about 1 mm, more preferably from about 20 to about 100 μm. Also, in this embodiment, the heat-activatable adhesive resin layer may partially or entirely cover the protruded parts of the patterned surface topography. Even in the case of covering the protruded parts by the heat-activatable adhesive resin layer, the thickness of the heat-activatable adhesive resin layer of the protruded parts differs from that of the recessed parts, thereby differentiating the adhesion force in-plane, so that the adhering area between the heat-activatable adhesive resin layer and the tile surface can be substantially adjusted. This tile adhering sheet contains a substrate and therefore, the heat-activatable adhesive resin layer may be continuous or discontinuous.

The tile adhering sheet of this embodiment can be available from heating a sheet to be used as a substrate to near its melting point or more, subjecting it to a general embossing process to prepare a patterned topography-imparted embossed sheet, that is, a substrate, and laminating the heat-activatable adhesive resin layer to this substrate by two-layer extrusion.

When the tile adhering sheet comprising a heat- activatable adhesive resin layer formed as described above is adhered to a plurality of tiles, the tile adhering sheet is partially adhered to the tile, so that the adhesion force to the tile can be easily adjusted by the change of the adhering area without changing the kind or thickness of the heat-activatable adhesive resin layer, because at least the adhering surface of the heat- activatable adhesive resin layer can be formed not on the entire surface but partially in the tile adhering sheet. As a result, the tiles having various surface topographies or outermost surface materials can be satisfactorily held during transportation, and troubles such as misalignment or detachment of tiles can be prevented from occurring when the tile adhering sheet is peeled off after the installation of such tiles.

In another embodiment, the adjustment of the adhering area in the heat-activatable adhesive resin layer can be achieved by providing a non-adhesive material or adhesion-decreasing material layer on the heat-activatable adhesive resin layer. In this case, even when not specifically indicated, the heat- activatable adhesive resin layer can be formed on a substrate . For example, a non-adhesive material film or sheet with partial openings may be laminated on the heat- activatable adhesive resin layer.

As for the film or sheet with partial openings, a sheet having openings surrounded by side parts of tape yarns (a laminate cloth) , which is obtained by orthogonally or diagonally stacking tape yarns into a grid and fixing grid intersections, can be used. For example, Figs. 7A and 7B show a tile adhering sheet 5 where a sheet having openings 11 is laminated on the tile adhering surface of the heat-activatable adhesive resin layer 4. Fig. 7A is a plan view. In the perspective view of Fig. 7B, a substrate 8 is provided below the heat-activatable adhesive resin layer 4, but this substrate may not be necessary. The tape yarn used for this sheet may be a yarn obtained by drawing the industrial film commonly used, such as polyethylene and polypropylene, and a high-density polyethylene drawn tape yarn is preferred in view of strength and the like.

The thickness of the tape yarn may be, for example, from about 5 to about 100 μm, preferably from about 10 to about 50 μm, depending on the thickness of the heat- activatable adhesive resin layer used. The width of the tape yarn may be variously selected depending on the tile size, the opening area and the like and may be, for example, from about 0.5 to about 10 mm, preferably from about 1 to about 5 mm. A plurality of the tape yarns are disposed at predetermined intervals by orienting the length of the tape yarns to a certain direction, a plurality of the tape yarns are disposed at predetermined intervals by orienting the length of the tape yarns to a different direction orthogonal or diagonal to the direction above, and these tape yarns are pressure-adher,ed under heating or via an adhesive, whereby the above-described sheet can be produced. Also, the length of tape yarns can be oriented in more than two directions (for example, in three directions) and laminated to form a sheet with partial openings .

A film where openings are partially provided by punching or the like may also be used as the film with partial openings. For example, Figs. 8A and 8B show a plan view and a perspective view of the tile adhering sheet 5 obtained by laminating such a film 12 on the tile adhering surface of the heat-activatable adhesive resin layer 4. In Fig. 8B, a substrate 8 is provided below the heat-activatable adhesive resin layer 4, but this substrate may not be necessary. The openings provided by punching may have various shapes and may have, for example, a circular, elliptical, triangular, rectangular or square shape.

Examples of the material which can be used for this film include polyester such as polyethylene, polypropylene and polyethylene terephthalate, polystyrene, nylon and a blend thereof. The thickness of the film is not limited but may be from about 5 to about 100 μm, preferably from about 10 to about 50 μm, depending on the thickness of the heat-activatable adhesive resin layer used.

For example, the film is punched into a certain shape by a punching blade, or a certain shape is cut and removed by using a cutter, a laser or the like, whereby a film or sheet with partial openings can be produced.

The opening ratio of the film or sheet with partial openings may be, depending on the intended use, from about 20 to about 90%, preferably from about 30 to about 80%, based on the area of the entire adhering surface of the tile adhering sheet. By selecting the appropriate opening ratio in this range, misalignment, detachment or the like of tiles during transportation can be prevented and at the same time, an optimal sheet release force can be obtained when separating this tile adhering sheet after tile installation.

Such a film or sheet with partial openings may be laminated on the tile adhering surface of the heat- activatable adhesive resin layer to form a tile adhering sheet. More specifically, the tile adhering sheet can be available from preparing a heat-activatable adhesive resin film or sheet and, for example, heat-laminating the above-described film or sheet with partial openings to the heat-activatable adhesive resin. In order to prevent the heat-activatable adhesive resin from excessively flowing and covering the entirety of the film with partial openings, the heat-lamination temperature is, for example, preferably melting point of heat-activatable adhesive resin plus about 30°C or less, more preferably melting point of heat-activatable adhesive resin plus about 20⁰C or less. More specifically, the heat- lamination temperature is, although not limited, preferably from about 60 to about 150°C.

Also, the adhering area between the heat-activatable adhesive resin layer and the tile surface can also be changed by partially applying an adhesion-decreasing material coating (also called a "tack-kill" coating) to the tile adhering surface of the heat-activatable adhesive resin layer. For example, Fig. 9 shows a tile adhering sheet 5 where such a coating 13 is applied to the tile adhering surface of the heat-activatable adhesive resin layer 4. The coating for decreasing the adhesion force means a coating using a material which does not exhibit the adhesive property at the temperature when adhering tiles at the production of a tile unit, and forms a non- adhesive portion on the tile adhering surface of the heat-activatable adhesive resin layer. Examples of the material which does not exhibit the adhesive property at the temperature (for example, about 80°C) when adhering tiles at the production of a tile unit include a composition containing (meth) acrylic acid ester polymer such as polymethyl methacrylate (PMMA) . In this case, a photoinitiator, a sensitizer, other reactive or non-reactive monomers or oligomers and the like may be added, for example, to methyl methacrylate (MMA) monomer to obtain a UV-curable composition. Also, irrespective of whether UV-curable or not, other materials may be used as long as the adhesive property is not exhibited at the above-described adhesion temperature, and examples thereof include printing ink commonly used.

The coverage of the adhesion-decreasing material coating is, depending on the intended use, from about 10 to about 80% (that is, the area of the exposed tile adhering surface is from about 20 to about 90%), preferably from about 20 to about 70% (the area of the exposed tile adhering surface is from about 30 to about 80%) . The thickness of the coating may be appropriately selected depending on the thickness of the heat- activatable adhesive resin layer, the viscosity characteristics of the coating composition used, the application method of the coating composition, and the like. For example, the thickness after drying and curing may be from about 0.1 to about 100 μm.

For example, in the case where the UV-curable composition described above is used for the adhesion- decreasing material coating, the UV-curable composition is printed on the tile adhering surface of the heat- activatable adhesive resin layer in a pattern such as stripe, dot or grid to occupy the coverage above, by using a general printing technique such as screen printing and off-set gravure printing, the irradiation atmosphere is then purged with nitrogen, if desired, and ultraviolet light is irradiated for curing using a mercury lamp, a metal halide lamp or the like, whereby a non-adhesive portion can be formed on the tile adhering surface of the heat-activatable adhesive resin layer.

When the tile adhering sheet having the thus-formed heat-activatable adhesive resin layer partially covered with a non-adhesive material or adhesion-decreasing material layer is adhered to a plurality of tiles, the tile adhering sheet is partially adhered to the tile, so that the adhesion force to the tile can be easily adjusted by the change of the adhering area without changing the kind or thickness of the heat-activatable adhesive resin layer, because the heat-activatably adherable area of the heat-activatable adhesive resin layer is present not in the entire surface but partially on the tile adhering sheet. As a result, the tiles having various surface topographies or outermost surface materials can be satisfactorily held during transportation, and troubles such as misalignment or detachment of tiles can be prevented from occurring when the tile adhering sheet is peeled off after the installation of such tiles. The tile unit of the present disclosure can be available from a method comprising a step of heat- adhering a tile adhering sheet having a heat-activatable adhesive property to a plurality of tiles in a state of the front faces of the plurality of tiles being in contact with the tile adhering sheet.

More specifically, the tile unit can be available from a method comprising a step of arranging a plurality of tiles in an array corresponding to the desired array of tiles after installation; a step of preparing a tile adhering sheet comprising a heat-activatable adhesive resin layer; a step of disposing the plurality of arrayed tiles and the tile adhering sheet by arranging the front faces of the plurality of tile to come into contact with the heat-activatable adhesive resin layer; and a step of heat-pressing the heat-activatable adhesive resin layer to adhere the heat-activatable adhesive resin layer to the plurality of tiles.

In the adhering step, although depending on the construction of the tile adhering sheet, it is preferred to closely contact the heat-activatable adhesive resin layer with the tile under pressure by allowing the heat- activatable adhesive resin layer to be softened at the contact surface with the tile but not allowing the adhesive layer to melt (heat-pressure adhesion) . The heat-adhesion temperature is preferably set to a temperature higher than the expected temperature during storage and transportation of the tile unit, in order to avoid detachment or misalignment of the tiles due to the decrease in the tile holding power during storage or transportation of the tile unit. Specifically, the heat- adhesion temperature is, but not limited to, preferably 60°C or more, more preferably 80°C or more.

In one preferred embodiment, a plurality of tiles may be preheated before the adhering step and the adhesion may be performed using the heated tiles.

It should be understood that tile adhering sheet of the present disclosure in all embodiments described above can be used to make the tile unit of the present disclosure.

The method of producing the tile unit is described below by referring to the production apparatus of the tile unit shown in Fig. 10.

A plurality of tiles 1 are arranged on a belt conveyor 2 in a desired array with front faces up. Then, if desired, the tiles 1 are preheated by passing the tiles 1 through a heating furnace 3 set to a temperature at which the heat-activatable adhesive resin is softened, for example, a temperature (for example, 80 to 110⁰C) less than the melting point. A tile adhering sheet 5 having a heat-activatable adhesive resin layer 4 (a substrate 8 may or may not be contained; the heat-activatable adhesive resin layer 4 may be partially formed) is unrolled from a sheet roll 6 having wound thereon the tile adhering sheet 5, and then disposed on the tiles 1 optionally preheated, by arranging the heat-activatable adhesive resin layer 4 to be in contact with the front faces of the tiles 1. The sheet 5 is then pressure- adhered by a roller 7, optionally in heated atmosphere, whereby the tile unit 10 of the present disclosure is formed after cutting into each unit. In order to facilitate the adhesion, the roller 7 may optionally be heated.

The tile unit of the present disclosure can be installed by a method comprising the steps of coating a tile bonding mortar or adhesive on a surface where tiles are to be installed (a tile installation surface) ; applying the tile unit of the present disclosure to the surface coated with the tile boding mortar or adhesive and partially or completely curing the tile bonding mortar or adhesive; and separating the tile adhering sheet from the tiles.

One example of the method of installing tiles of the present disclosure is described in more detail by referring to Fig. 11. The tile unit 10 of the present disclosure is produced as described above, the tile unit is transported to an installation site, a known tile bonding mortar or adhesive 14 such as modified silicone adhesive is coated on a tile installation surface such as outer surface of a building structure 15 at the installation site and, if desired, smoothed and flattened, and the tile unit 10 is attached to the surface coated with the adhesive 14. After leaving to stand for a predetermined time (from about 1 to about 3 hours) , when the tile bonding mortar or modified silicone adhesive is somewhat cured and tiles are fixed at least to the extent of not moving by the own weight, the tile adhering sheet 5 is separated from the tiles 1. Fig. 10 shows a tile adhering sheet 5 which is being separated from the top at the interface between the tiles 1 and the heat-activatable adhesive resin layer 4. By using the tile adhering sheet of the present disclosure, even if the tile bonding mortar or modified silicone adhesive is partially-cured, the tile adhering sheet can be separated without leaving glue residue on the tiles while not causing misalignment or detachment of the tiles, and the fine adjustment of the tile position can be then performed. Particularly, by using the preferred tile adhering sheet of the present disclosure having an appropriately adjusted adhesion force for various tiles, the tile adhering sheet can be separated without leaving glue residue on the tiles during installation while allowing the tile adhering sheet to provide a sufficiently high holding power during transportation, and at the same time, the necessary adhesion force and the desired release force can be easily adjusted in order not to cause misalignment or detachment of the tiles.

Also, when in the step of separating the tile adhering sheet from the tiles, for example, water is sprayed to ingress between the tile adhering sheet 5 and the tiles 1 (indicated by the arrow in Fig. 10) before and/or during separation, the release force of the tile adhering sheet can be advantageously decreased.

When the separation of the tile adhering sheet is performed with spraying water so as to ingress between the tile adhering sheet and the tiles, the tile adhering sheet can be separated more easily. Although not restrained by any theory, this phenomenon is considered to be explained as follows. The front face of the tiles in general has relatively high affinity for water due to glaze, hydrophilic surface coating or surface topography, whereas with respect to the adhering surface of the tile adhering sheet of the present disclosure, the heat- activatable adhesive resin is generally hydrophobic and therefore, the adhering surface of the tile adhering sheet has relatively low affinity for water. Accordingly, when water is sprayed to ingress between the tile adhering sheet and the tiles during separation of the tile adhering sheet, the front face of the tiles is wetted with water and the hydrophobic adhering surface of the tile adhering sheet becomes to easily separate from the front face of the tile. In the preferred tile adhering sheet of the present disclosure, when a patterned surface topography having recesses and projections is at least partly remaining on the adhering surface of the tile adhering sheet even after bonding of the tiles or when a film or sheet with partial openings is provided on the adhering surface, water tends to ingress through the void or gap in the adhering surface or through the discontinuous portion of the adhering surface structure (for example, the boundary between the film with partial openings and the adhesive layer) and therefore, the effect is particularly great. The effect of water spraying to the conventional tile adhering sheet using kraft paper and starch glue is to facilitate the cohesive failure of the starch glue and aid the separation of the adhesive sheet, and this is utterly different from the above-described effect of the present disclosure .

The tile unit of the present disclosure can be applied directly to a tile installation surface such as surface of a building structure. Alternatively, the tile unit of the present disclosure can also be installed to a pre-cast plate in a factory and the pre-cast plate can be then applied to a building structure in the conventional manner.

EXAMPLES

The present disclosure is described and illustrated below by referring to Examples. Unless otherwise indicated, the percentage, part and ratio are on the weight basis.

Evaluation Method 1 of Tile Unit (Examples 1 to 5)

The tile unit is hung in the vertical direction by holding the end part and swayed back and forth, and whether detachment of tiles occurs or not is observed. Also, a tile bonding mortar is coated on a wall, the tile unit is attached to the wall and the sheet is peeled off from the tiles after curing the mortar. The surface of the tile is observed and whether there is a residue or not is observed. Evaluation Method 2 of Tile Unit (Examples 6 to 16)

The tile unit is hung in the vertical direction by holding the end part and swayed back and forth, and whether dropping or detachment of tiles occurs or not is observed. Then, a modified silicone adhesive is coated on a base of the outer wall of a building, and after smoothing and flattening the adhesive face by combing, another tile unit produced in the same manner is attached to the adhesive face and left standing for 2 hours.

Thereafter, the tile adhering sheet is peeled off. The surface of the tile is observed and whether there is a residue or not is observed. Furthermore, whether the tiles are misaligned or detached from the outer wall is observed. Example 1

An 80 μm-thick sheet comprising a blend of polypropylene and polyethylene (6:4) was used as the substrate, and ZAIKTHENE (trade name) available from Sumitomo Seika Chemicals Co., Ltd., which is an ethylene- acrylic acid copolymer (EAA) emulsion, was coated thereon and dried to form a heat-activatable adhesive resin layer having a thickness of 15 μm. The melting point of this heat-activatable adhesive resin layer was 90°C determined by DSC (differential scanning calorimetry) .

Tiles were arrayed at equal intervals with front faces up and heated at 80°C in an oven. The sheet above cut into a size of 200 mm x 280 mm was disposed by arranging the heat-activatable adhesive resin layer to come into contact with the front faces of the tiles, and a pressure was applied thereto, as a result, the heat- activatable adhesive resin was softened and adhered to the tiles. After enough cooling of the tiles, a tile unit where a plurality of tiles were adhered to the sheet was formed.

This tile unit was evaluated according to Evaluation Method 1 of Tile Unit and the results obtained are shown in Table 1 below. Example 2

The same sheet as in Example 1 was used as the substrate, and N0908 (article number) available from Du Pont-Mitsui Polychemicals Co., Ltd., which is an ethylene-methacrylic acid copolymer, was extruded and laminated thereon to a thickness of 80 μm by using a T- die to form a heat-activatable adhesive resin layer. The melting point of this heat-activatable adhesive resin layer was 99⁰C determined by DSC (differential scanning calorimetry) . The fabrication and evaluation of a tile unit were performed in the same manner as in Example 1 and the results obtained are shown in Table 1 below. Example 3 The same sheet as in Example 1 was used as the substrate, and A210K (trade name) available from Japan Polyethylene Corp., which is an ethylene-acrylic acid copolymer, was extruded and laminated thereon to a thickness of 80 μm by using a T-die to form a heat- activatable adhesive resin layer. The melting point of this heat-activatable adhesive resin layer was 98°C determined by DSC (differential scanning calorimetry) . The fabrication and evaluation of a tile unit were performed in the same manner as in Example 1 and the results obtained are shown in Table 1 below. Example 4 (Comparison)

Tiles were arrayed at equal intervals with front faces up and a sheet obtained by applying starch glue to the entire surface of kraft paper in a size of 200 mm x 280 mm was attached thereon and well dried at 100°C for about 10 minutes. After enough cooling of the tiles, a tile unit where a plurality of tiles were adhered to the sheet was formed. The evaluation of the tile unit was performed in the same manner as in Example 1 and the results obtained are shown in Table 1 below. Example 5 (Comparison)

The same sheet as in Example 1 was used as the substrate, and a pressure-sensitive adhesive obtained by adding 100 parts by weight of a petroleum-based tackifier to 100 parts by weight of a styrene-isoprene copolymer was laminated on the substrate to a thickness of 30 μm. A tile unit was formed in the same manner as in Example 1, except that the pressure-sensitive adhesive layer was adhered to the tiles. The evaluation of the tile unit was performed in the same manner as in Example 1 and the results obtained are shown in Table 1 below. Table 1:

Example 6

A 90 μm-thick sheet formed of a high-density polyethylene containing talc added thereto was used as the substrate, and an ethylene-ethyl acrylate (EEA) copolymer having an ethyl acrylate (EA) content of 25% was extruded and laminated to a thickness of 60 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet. Subsequently, a sheet obtained by orthogonally stacking high-density polyethylene drawn tape yarns into a grid and fixing grid intersections (thickness of tape yarn: 30 μm, width of tape yarn: 2 mm, opening ratio: 58%) was contacted with the heat-activatable adhesive resin layer and heat- laminated at about 80°C to form a tile adhering sheet. The melting point of this heat-activatable adhesive resin layer was 91⁰C determined by DSC (differential scanning calorimetry) .

12 Tiles (45 mm (width) x 145 mm (length) x 5 mm (thickness) ) were arrayed in a palette by creating a joint gap of about 5 mm with front faces up. The tiles were preheated at 80⁰C, the tile adhering sheet cut into a size of 200 mm x 280 mm was disposed by arranging the heat-activatable adhesive resin layer to come into contact with the front faces of the tiles, and a pressure was applied thereto at 8O⁰C, as a result, the heat- activatable adhesive resin was softened and adhered to the tiles. After enough cooling of the tiles, a tile unit where a plurality of tiles were adhered to the sheet was formed.

This tile unit was evaluated according to Evaluation Method 2 of Tile Unit and the results obtained are shown in Table 2 below.

Also, according to the same method as in Evaluation Method 2 of Tile unit, two tile units were attached to a base of the outer wall of a building and left standing for 2 hours. As for one tile unit, it was visually confirmed that the sheet was entirely adhered to the base (shown in Fig. 12) , and while measuring the sheet release force by a push-pull gauge, the tile adhering sheet was peeled off. As for the other tile unit, a part of the tile adhering sheet was peeled off, water was sprayed in the periphery of the tile adhering sheet, and the sheet was left standing for 5 minutes. Afterwards, the adhering area (indicated by surrounding with a white line in Fig. 13) was visually observed, and while measuring the release force by a push-pull gauge, the tile adhering sheet was peeled off. The results of comparison between the presence and the absence of water spraying are shown in Table 3. Example 7

The same sheet and ethylene-ethyl acrylate (EEA) copolymer as in Example β were used as the substrate and heat-activatable adhesive resin, respectively, and this heat-activatable adhesive resin was extruded and laminated to a thickness of 60 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet, thereby forming a tile adhering sheet. The fabrication and evaluation of a tile unit were performed in the same manner as in Example 6, and the results obtained are shown in Tables 2 and 3 below. Also, the comparison between before water spraying and 5 minutes after water spraying are shown in Figs. 14 (in which the sheet is entirely adhered to the base) and 15 (in which the adhering area is indicated by surrounding with a white line) , respectively. Example 8 The same sheet as in Example 6 was used as the substrate, and an ethylene-methyl methacrylate (EMMA) copolymer having a methyl methacrylate (MMA) content of 9% was extruded and laminated thereon to a thickness of 80 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet, thereby forming a tile adhering sheet. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 2 below. Example 9

The same sheet as in Example 6 was used as the substrate, and an ethylene-acrylic acid (EAA) copolymer having an acrylic acid (AA) content of 7% was extruded and laminated thereon to a thickness of 80 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet , thereby forming a tile adhering sheet . The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 2 below . Example 10 (Comparison)

12 Tiles ( 45 mm (width) x 145 mm ( length) x 5 mm (thickness ) ) were arrayed in a palette by creating a j oint gap of about 5 mm with front faces up, and a sheet obtained by applying starch glue to the entire surface of kraft paper in a size of 200 mm x 280 mm was attached thereon and well dried at 100°C for about 10 minutes . After enough cooling of the tiles , a tile unit where a plurality of tiles were adhered to the sheet was formed . The results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 2 below . Table 2 :

1 ) After enough cooling of the tiles , the tile unit was hung in the vertical direction by holding the end part and swayed back and forth, and dropping or separation of tiles was observed . ++ : no dropping and no separation, + : no dropping .

2 ) ++ : No misalignment of tiles and no detachment from outer wall , + : misalignment occurred depending on the tile , but no detachment from outer wall .

3 ) + : No residue, - : glue remained . Table 3 :

Example 11 The same sheet and ethylene-ethyl acrylate (EEA) copolymer as in Example 6 were used as the substrate and heat-activatable adhesive resin, respectively, and this heat-activatable adhesive resin was extruded and laminated to a thickness of 60 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet. Subsequently, a high-density polyethylene film having provided therein many circular holes (thickness: 50 μm, diameter of hole: 6 mm, opening ratio: 58%) was contacted with the heat-activatable adhesive resin layer and heat-laminated at about 8O⁰C to form a tile adhering sheet. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below.

Example 12

The same sheet and ethylene-ethyl acrylate (EEA) copolymer as in Example 6 were used as the substrate and heat-activatable adhesive resin, respectively, and this heat-activatable adhesive resin was extruded and laminated to a thickness of 60 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet. Subsequently, a UV-curable composition containing a methyl methacrylate monomer was printed on the adhesive layer in a grid pattern with a line width of 2 mm by using a screen printer to leave a non-printed portion at 58%, and ultraviolet light was irradiated using a metal halide lamp to cure the printed grid pattern, thereby forming a tile adhering sheet. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below. Example 13

The same sheet and ethylene-ethyl acrylate (EEA) copolymer as in Example 6 were used as the substrate and heat-activatable adhesive resin, respectively, and this heat-activatable adhesive resin was extruded and laminated to a thickness of 60 μm by using a T-die to form a heat-activatable adhesive resin layer throughout one surface of the sheet. Subsequently, a die having truncated pyramidal recesses (sides of peak of truncated pyramid: each 5 mm, sides of bottom: each 7 mm, height: 50 μm, area ratio of peak of truncated pyramid to entire sheet processing surface: 50%) was heated at 80°C and pressed to the adhesive layer for 2 seconds to transfer the topography of the die to the adhesive layer, thereby forming a tile adhering sheet. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below. Example 14 The substrate used in Example 6 was embossed to form rectangular recesses (sides: each 5 mm, sides of bottom: each 7 mm, height: 50 μm, area ratio of recesses: 50%) in the surface on which a heat-activatable adhesive resin layer is to be formed. On the surface where the heat- activatable adhesive resin layer is to be formed, the ethylene-ethyl acrylate (EEA) copolymer used in Example 6 was extruded and laminated to a thickness of 60 μm by using a T-die, whereby a tile adhering sheet having a heat-activatable adhesive resin layer provided in the recesses of the substrate was formed. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below. Example 15

The ethylene-ethyl acrylate (EEA) copolymer used in Example 6 was extruded and laminated on the substrate used in Example 6 to a thickness of 60 μm by using a special shaped die to form a tile adhering sheet where an adhesive layer in a rectangular pattern having one side length of 5 mm and a thickness of 60 μm and having a coated area ratio of 58% was provided to the substrate. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below. Example 16

The ethylene-ethyl acrylate (EEA) copolymer used in Example 6 was extruded and laminated on the substrate used in Example 6 to a thickness of 60 μm by using a slit-shaped die to form a tile adhering sheet where an adhesive layer in a stripe shape having a width of 5 mm and a thickness of 60 μm and having a coated area ratio of 56% was provided to the substrate. The fabrication of a tile unit was performed in the same manner as in Example 6, and the results of the evaluation performed according to Evaluation Method 2 of Tile Unit are shown in Table 4 below. Table 4 :

1) After enough cooling of the tiles, the tile unit was hung in the vertical direction by holding the end part and swayed back and forth, and dropping or separation of tiles was observed. ++: no dropping and no separation, +: no dropping.

2) ++ : No misalignment of tiles and no detachment from outer wall, +: misalignment occurred depending on the tile, no detachment from outer wall.

3) +: No residue, -: glue remained.

INDUSTRIAL APPLICABILITY

According to the tile adhering sheet and tile unit of the present disclosure, as compared with the conventional tile adhering sheet of kraft paper and the tile unit using the sheet, not only good dimensional stability, no glue residue and excellent aesthetic appearance but also high workability and capability of low-cost installation are ensured, and the separation property can be adjusted by adjusting the area of the heat-activatable adhesive resin layer of the tile adhering sheet while holding the adhesion force depending on various tiles. The present disclosure is apparently useful in industry.

Claims

1. A tile unit which comprises a tile adhering sheet comprising a heat-activatable adhesive resin layer, and a plurality of tiles having front faces, the tile adhering sheet being heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer.

2. The tile unit as claimed in claim 1, wherein the tile adhering sheet consists of a heat-activatable adhesive resin layer.

3. The tile unit as claimed in claim 1, wherein the tile adhering sheet comprises a substrate and a heat- activatable adhesive resin layer formed on the substrate.

4. The tile unit as claimed in claim 2, wherein the heat-activatable adhesive resin layer has openings or a patterned surface topography having recesses and projections, whereby the tile adhering sheet is partially heat-activatably adhered to the front faces of the tiles.

5. The tile unit as claimed in claim 3, wherein the heat-activatable adhesive resin layer is partially formed on the substrate or has a patterned surface topography having recesses and projections, whereby the tile adhering sheet is partially heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer.

6. The tile unit as claimed in claim 1, wherein the tile adhering sheet comprises a heat-activatable adhesive resin layer and a non-adhesive material layer or adhesion-decreasing material layer partially formed on the heat-activatable adhesive resin layer, whereby the tile adhering sheet is partially heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer.

7. The tile unit as claimed in claim 1, wherein the tile adhering sheet comprises a substrate, a heat- activatable adhesive resin layer formed on the substrate, and a non-adhesive material layer or adhesion-decreasing material layer partially formed on the heat-activatable adhesive resin layer, whereby the tile adhering sheet is partially heat-activatably adhered to the front faces of the tiles by the heat-activatable adhesive resin layer.

8. A tile adhering sheet comprising a heat- activatable adhesive resin layer, whereby the tile adhering sheet has a surface which can partially heat- activatably adhere to a tile.

9. The tile adhering sheet as claimed in claim 8, consisting of a heat-activatable adhesive resin layer, having openings or a patterned surface topography having recesses and projections.

10. The tile adhering sheet as claimed in claim 8, comprising a substrate and a heat-activatable adhesive resin layer, the heat-activatable adhesive layer being partially formed on the substrate or having a patterned surface topography having recesses and projections.

11. The tile adhering sheet as claimed in claim 8, comprising a heat-activatable adhesive resin layer and a non-adhesive material layer or adhesion-decreasing material layer partially formed on the heat-activatable adhesive resin layer.

12. The tile adhering sheet as claimed in claim 8, comprising a substrate, a heat-activatable adhesive resin layer formed on the substrate, and a non-adhesive material layer or adhesion-decreasing material layer partially formed on the heat-activatable adhesive resin layer.

13. The tile adhering sheet as claimed in any one of claims 8 to 12, wherein the heat-activatable adhesive resin layer comprises a thermoplastic resin.

14. The tile adhering sheet as claimed in any one of claims 8 to 12, wherein the heat-activatable adhesive resin layer comprises a resin selected from the group consisting of olefin-vinyl acetate copolymer, olefin-

(meth) acrylic acid copolymer, olefin- (meth) acrylic acid ester copolymer, polyolefin, polyamide, polyester and polylactic acid.

15. The tile adhering sheet as claimed in any one of claims 8 to 12, wherein the heat-activatable adhesive resin layer comprises a resin having a melting point of about 60°C or more.

16. The tile adhering sheet as claimed in any one of claims 8 to 12, wherein the elongation of the tile adhering sheet in one dimension is 1% or less at 60°C based on the length of the sheet in the same dimension at 25°C.

17. The tile adhering sheet as claimed in any one of claims 8 to 12, wherein the tile adhering sheet is transparent or translucent.

18. A method of installing tiles comprising: coating a tile bonding mortar or adhesive on a surface where tiles are to be installed; applying the tile unit claimed in any one of claims 1 to 7 to said surface coated with the tile boding mortar or adhesive to at least partially cure the tile bonding mortar or adhesive; and separating the tile adhering sheet from the tiles.

19. The method of installing tiles as claimed in claim 18, wherein the separating step comprises spraying water to the tile unit before and/or during separation of the tile adhering sheet from the tiles.