JP2021042662A - Moisture-proof film - Google Patents

Abstract

To provide a moisture-proof film used for a decorative material for a floor where curving or warping is restrained from being occurred even when a decorative sheet with low moisture permeability is laminated on a front surface of woody base material.SOLUTION: The present invention relates to a moisture-proof film used in a decorative material for a floor that is in a laminated structure having, from a front surface to a rear surface, a decorative sheet 1 with at least one thermoplastic resin layer, a woody base material 3 of which dimensional change amount per 1% water content rate is greater than 0.02% and of which average water content rate is 6-10 wt.%, and the moisture-proof film 5. The moisture-proof film has a water-vapor permeability equal to or smaller than 1 g/m2 24 hr and is a laminate body having a primer layer consisting of at least one selected from a group consisting of an ester-based resin, an urethane resin, an acrylic resin, a polycarbonate-based resin, a polyvinyl chloride-acetic-acid copolymer, a polyvinyl butyral-based resin and a nitro cellulose-based resin, and an aluminum vapor deposition layer in this order on one surface of the thermoplastic resin layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a floor decorative material in which warpage and towing are suppressed.

Conventionally, as a wood-based decorative board used as a decorative material for the floor of a house, a natural wood design is provided on the upper surface of a wooden base material (for example, hardwood lauan plywood) obtained from high-quality raw wood via an adhesive. It is known that a decorative sheet is attached.

As the wood base material, the above-mentioned broad-leaved lauan is often used, but in recent years, it is difficult to obtain raw wood due to the scarcity of natural resources, restrictions on logging, etc., and the material shortage is progressing. This problem is especially serious for hardwoods such as Lauan. Therefore, the development of a wood base material that can be used in place of Lauan plywood is underway. As a Lauan alternative material, for example, a wood board formed by molding and solidifying wood fibers or wood pieces separated from coniferous plywood and wood waste wood with an adhesive (for example, medium density wood fiber board: MDF, high density wood fiber board). : HDF, particle board: PB), there are early-maturing plywood consisting of early-maturing trees.

However, these Lauan alternative materials have a problem that the amount of dimensional change per 1% change in water content is larger than that of Lauan plywood, and the dimensional change is likely to occur in response to changes in the surrounding environment. Specifically, the amount of dimensional change per 1% water content of Lauan plywood is 0.015 to 0.02%, but it is about 0.045% for MDF and PB, and 0 for softwood plywood (for example, radiata pine). It is about .025%. Therefore, the Lauan alternative material has a characteristic that warpage and towing (the right angle of the floor surface shifts) are likely to occur due to a change in humidity.

In order to improve the above problem, it has been proposed to laminate a moisture-proof sheet on the back surface of the Lauan alternative material (for example, Patent Documents 1 to 3). However, a moisture-proof sheet moisture permeability at most 20 g / m of about 2 · ²⁴ hr according to Patent Documents 1 to 3, in order to prevent bending stringing warp or lauan alternative material is insufficient performance. Particularly in recent years, moisture permeability is low (less than 2g / m 2 · ²⁴ hours) on the front surface of the lauan alternative material for many cases of laminating a decorative sheet, from equal to or a front surface of the back surface of the moisture permeability It is required to reduce the moisture permeability.

From the above, even when a Lauan alternative material with a dimensional change amount of more than 0.02% per 1% moisture content change is used as the wood base material and a decorative sheet with low moisture permeability is laminated on the front surface thereof. It is desired to develop a decorative material for floors in which the occurrence of warpage and towing is suppressed.

Japanese Unexamined Patent Publication No. 2001-193267 Japanese Unexamined Patent Publication No. 2001-260109 Japanese Unexamined Patent Publication No. 2006-097321

The present invention uses a Lauan alternative material having a dimensional change amount of more than 0.02% per 1% water content change as a wood base material, and even when a decorative sheet having low moisture permeability is laminated on the front surface thereof. It is an object of the present invention to provide a decorative material for floors in which the occurrence of warpage and towing is suppressed.

As a result of diligent research, the present inventor has found that the above object can be achieved when a specific moisture-proof film is used, and has completed the present invention.

That is, the present invention relates to the following wood base material.
1. 1. From the front surface toward the back surface, floors with a decorative sheet comprising at least one layer of a thermoplastic resin layer, and a wood substrate, a laminated structure in which moisture permeability comprises a moisture-proof film is not more than 7g / m 2 · ²⁴ hours The wood base material used for decorative materials.
The amount of dimensional change per 1% moisture content change is larger than 0.02%,
The average water content is 6 to 10% by weight, and the water content in the central part is in the range of -1% to + 2% as compared with the water content in the peripheral part.
A wood base material characterized by that.
2. The wood substrate is at least one selected from the group consisting of medium density wood fiberboard (MDF), high density wood fiberboard (HDF), particle board (PB), coniferous plywood and early-maturing plywood. Item 2. The wood base material according to Item 1.
3. 3. The decorative sheet, the moisture permeability is less than 7 g / m 2 · ²⁴ hours, wood substrate according to Item 1 or 2.

Hereinafter, the floor decorative material of the present invention will be described in detail.

The floor decorative material of the present invention is a floor decorative material in which a decorative sheet is laminated on the front surface of a wood base material and a moisture-proof film is laminated on the back surface of the wood base material.
(1) said wood substrate is greater than the amount of dimensional change per 1% moisture content change is 0.02%, (2) the moisture-proof film, the moisture permeability is less than 7 g ^{/ m} 2 · 24 hours It is characterized by. The moisture permeability is a measured value in a temperature of 40 ° C. and a humidity of 90% RH environment according to JIS Z0208 (moisture permeability test method (cup method)). Hereinafter, the moisture permeability in the present specification indicates a measured value under the relevant conditions.

Floor decorative material of the present invention having the above characteristics, moisture permeability by having a moisture-resistant films is less than 7g / m 2 · ²⁴ hours, moisture permeability of the back surface wood substrate is kept low. Therefore, even when a decorative sheet having low moisture permeability is laminated on the front surface of a wood base material using a Lauan alternative material having a dimensional change amount of more than 0.02% per 1% water content change, the wood base is used. Since the moisture permeability of the front surface and the back surface of the material can be set to the same level, the occurrence of warping and bending of the floor decorative material is sufficiently suppressed. Such a floor decorative material of the present invention is suitable as a floor decorative material to be applied to the floor surface of various buildings and a floor decorative material used for floor heating as a special purpose.

Hereinafter, each configuration of the floor decorative material of the present invention will be described.
(Wood base material)
As the wood base material of the present invention, a Lauan alternative material is used. That is, it is a material that replaces the conventional Lauan plywood and the like, and is, for example, at least one such as medium density wood fiberboard (MDF), high density wood fiberboard (HDF), particle board (PB), coniferous plywood, and early-maturing plywood. Use seeds. Examples of early-maturing trees include poplar, falcata, acacia, chamelele, eucalyptus, and terminaria. These Lauan alternative materials have a dimensional change of more than 0.02% per 1% change in water content.

The "dimension change amount per 1% water content" in the present specification is the dimensional change amount measured by the following procedure.
(1) Prepare a test piece of a wood base material cut into a size of 300 mm × 303 mm.
(2) Measure the current dimensions (lengths of four sides) of the test piece with a caliper under a normal temperature (25 ° C.) environment. (3) The test piece is left in an oven at 40 ° C. (humidity-free, dry atmosphere ≈ 0%) for 1 week.
(4) After one week, the weight and dimensions (length of four sides) of the test piece are measured.
(5) Measure the dimensional change rate per 1% water content change from the measurement data under both conditions.

The thickness of the wood base material is not particularly limited, but is preferably about 2 to 15 mm, more preferably about 2 to 12 mm.

In the present invention, the average moisture content of the wood base material is 6 to 10% by weight, and the moisture content of the central portion is that of the peripheral portion, in preparation for the case where the floor decorative material is cut and used according to the construction site. It is preferable to use a wood base material having a water content in the range of -1% to + 2%. When the size of the wood base material is, for example, about 150 mm in length × 1840 mm in width (particularly, the length of the short side is 200 mm or less), the wood base material is warped or towed due to the uneven water content in the central part and the peripheral part. Is likely to occur. Therefore, by setting the moisture content characteristic of the wood base material to the above conditions, it is possible to suppress the occurrence of warpage and towing even when the floor decorative material is cut and used. When the floor decorative material is cut and used, specifically, it is assumed that the floor decorative material is applied to the corner portion (near the wall or around the pillar) of the room where the floor decorative material is applied.

The average moisture content of the wood substrate is preferably 6 to 10% by weight, more preferably 6.5 to 8% by weight. When the average moisture content is within the above range, it is easy to suppress the occurrence of towing and warping after cutting. Among them, when the floor decorative material is used for floor heating, it is preferable to set the average water content to 6 to 9% by weight.

The water content of the wood substrate is preferably in the range of -1% to + 2%, preferably in the range of -0.5% to + 1%, in the water content of the central part as compared with the water content of the peripheral part. Is more preferable. The peripheral portion of the wood base material means a range of 5 cm around the wood base material, and the central portion of the wood base material means the inside of the wood base material excluding the peripheral portion.

The average water content and the difference in water content of the wood base material in the present specification (hereinafter, "water content difference" indicates the difference in water content between the peripheral portion and the central portion of the wood base material) are measured by the following procedure. Is the value to be.
(A) As shown in FIG. 3, a wood base material having a length of 303 mm and a width of 1818 mm is prepared.
(B) The area 5 cm from the periphery of the wood base material is the peripheral portion, and the inside thereof is the central portion. As shown by 1 to 35 in FIG. 3, 35 samples of 5 cm × 5 cm are uniformly collected, and the water content is measured by the total dry method. The total drying method is a method in which each sample is left in an oven at 105 ° C. for 3 days, and then the water content of each sample is measured from the following formula. Before leaving is called before processing, and after leaving is called after processing.

Moisture content (%) = {(weight before treatment-weight after treatment) / weight after treatment} x 100
(C) Let the average value of 35 samples be the "average water content".
(D) The value obtained by subtracting the average value of the samples (20 pieces) in the peripheral part from the average value of the samples (15 pieces) in the central part is defined as the "moisture content difference".
(Cosmetic sheet)
A decorative sheet is laminated on the front surface of the wooden base material. Temperature 40 ° C. As the decorative sheet, the moisture permeability thereof is preferably less than 7g ^{/ m} 2 · 24 hours at 90% humidity, the following 5g ^{/ m} 2 · 24 hours is more preferable. The structure of the decorative sheet is not limited, but for example, it is preferable that the base sheet has a pattern layer (solid ink layer / pattern ink layer), a transparent resin layer, and a surface protection layer in this order. Hereinafter, this decorative sheet will be described exemplarily.

The base sheet includes 1) thin paper, high-quality paper, kraft paper, Japanese paper, titanium paper, resin-impregnated paper, inter-paper reinforced paper, and 2) wood fiber, glass fiber, asbestos, polyester fiber, vinylon fiber, and rayon. Examples thereof include one or more laminates of woven fabrics or non-woven fabrics made of fibers and the like, and 3) sheets made of synthetic resins such as polyolefins, polyesters, polyacrylics, polyamides, polyurethanes and polystyrenes.

The thickness of the base sheet is preferably about 20 to 300 μm. The base sheet may be colored if necessary. Further, the surface may be subjected to surface treatment such as corona discharge treatment, plasma treatment, ozone treatment and the like.

The pattern layer is composed of a pattern ink layer and / or a solid ink layer. The pattern layer can be formed by a printing method such as gravure printing, offset printing, or silk screen printing. Examples of the pattern of the pattern ink layer include a wood grain pattern, a stone grain pattern, a cloth pattern, a leather pattern, a geometric pattern, characters, symbols, line art, and various abstract patterns. The solid ink layer is obtained by solid printing of colored ink. The pattern layer is composed of one or both of the pattern ink layer and the solid ink layer.

The ink used for the pattern layer includes chlorinated polyethylene such as chlorinated polyethylene and chlorinated polypropylene, polyester, polyurethane composed of isocyanate and polyol, polyacrylic, polyvinyl acetate, polyvinyl chloride, and vinyl chloride-vinyl acetate. A polymer, a cellulose-based resin, a polyamide-based resin, or the like is used by mixing one or more kinds, and a pigment, a solvent, various auxiliary agents, and the like are added thereto to form an ink. Among these, from the viewpoint of environmental problems, adhesion to the surface to be printed, etc., one or a mixture of two or more kinds of polyurethane, polyacrylic, polyamide resin and the like composed of polyester, isocyanate and polyol is preferable.

The transparent resin layer is not particularly limited as long as it is a transparent resin layer, and can be preferably formed by, for example, a transparent thermoplastic resin.

Specifically, both soft, semi-hard or hard polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene-acrylic acid ester. Examples thereof include polymers, ionomers, acrylic acid esters, and methacrylic acid esters. Among the above, polyolefin-based resins such as polypropylene are preferable.

The transparent resin layer may be colored. In this case, a colorant may be added to the thermoplastic resin. As the colorant, a pigment or dye used in the pattern layer can be used.

The transparent resin layer includes a filler, a matting agent, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a radical scavenger, and a soft component (for example, rubber). Various additives such as, etc. may be included.

The surface protective layer (transparent surface protective layer) is provided to impart surface physical properties such as scratch resistance, abrasion resistance, water resistance, and stain resistance required for a decorative sheet. As the resin forming the surface protective layer, a curable resin such as a thermosetting resin or an ionizing radiation curable resin is preferable. In particular, the ionizing radiation curable resin is preferable from the viewpoint of high surface hardness, productivity and the like.

Examples of the heat-curable resin include unsaturated polyester resin, polyurethane resin (including two-component curable polyurethane), epoxy resin, aminoalkyd resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, and melamine. -Urea cocondensation resin, silicon resin, polysiloxane resin and the like can be mentioned.

A curing agent such as a cross-linking agent and a polymerization initiator, and a polymerization accelerator can be added to the resin. For example, as a curing agent, isocyanate, organic sulfonate, etc. can be added to unsaturated polyester resin, polyurethane resin, etc., organic amine, etc. can be added to epoxy resin, peroxide such as methyl ethyl ketone peroxide, azoisobutylnitrile, etc. A radical initiator can be added to the unsaturated polyester resin.

Examples of the method for forming the surface protective layer with the thermosetting resin include a method in which a solution of the thermosetting resin is applied by a coating method such as a roll coating method or a gravure coating method, and dried and cured. The amount of the solution applied is approximately 5 to 30 μm, preferably about 5 to 20 μm in terms of solid content.

The ionizing radiation curable resin is not limited as long as it is a resin that undergoes a cross-linking polymerization reaction by irradiation with ionizing radiation and changes into a three-dimensional polymer structure. For example, one or more of prepolymers, oligomers and monomers having a polymerizable unsaturated bond or an epoxy group in the molecule that can be crosslinked by irradiation with ionizing radiation can be used. For example, acrylate resins such as urethane acrylates, polyester acrylates and epoxy acrylates; silicon resins such as siloxane; polyester resins; epoxy resins and the like can be mentioned.

Examples of ionizing radiation include visible light, ultraviolet rays (near ultraviolet rays, vacuum ultraviolet rays, etc.), X-rays, electron beams, ionizing rays, etc. Among them, ultraviolet rays and electron beams are preferable.

As the ultraviolet source, a light source of an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or a metal halide lamp can be used. The wavelength of ultraviolet rays is about 190 to 380 nm.

As the electron beam source, for example, various electron beam accelerators such as Cockcroft-Walt type, bandegraft type, resonance transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type can be used. The energy of the electron beam is preferably about 100 to 1000 keV, more preferably about 100 to 300 keV. The irradiation amount of the electron beam is preferably about 2 to 15 Mrad.

The ionizing radiation curable resin is sufficiently cured by irradiating it with an electron beam, but when it is cured by irradiating it with ultraviolet rays, it is preferable to add a photopolymerization initiator (sensitizer).

In the case of a resin system having a radically polymerizable unsaturated group, the photopolymerization initiator is, for example, acetophenone, benzophenone, thioxanthone, benzoin, benzoin methyl ether, Michler benzoyl benzoate, Michler ketone, diphenyl sulfide, dibenzyl disulfide. , Diethyl oxide, triphenylbiimidazole, isopropyl-N, N-dimethylaminobenzoate and the like can be used. In the case of a resin system having a cationically polymerizable functional group, at least one of, for example, an aromatic diazonium salt, an aromatic sulfonium salt, a metallocene compound, a benzoin sulfonic acid ester, and a freeleoxysulfoxonium diallyl iodosyl salt. Can be used.

The amount of the photopolymerization initiator added is not particularly limited, but is generally about 0.1 to 10 parts by weight with respect to 100 parts by weight of the ionizing radiation curable resin.

As a method of forming the protective layer with the ionizing radiation curable resin, for example, a solution of the ionizing radiation curable resin may be applied by a coating method such as a gravure coating method or a roll coating method. The amount of the solution applied is approximately 5 to 30 μm, preferably about 5 to 20 μm as a solid content.

In order to further impart scratch resistance and abrasion resistance to the surface protective layer formed of the ionizing radiation curable resin, an inorganic filler may be blended. Examples of the inorganic filler include powdered aluminum oxide, silicon carbide, silicon dioxide, calcium titanate, barium titanate, magnesium pyrobolate, zinc oxide, silicon nitride, zirconium oxide, chromium oxide, iron oxide, and boron nitride. Examples thereof include diamond, Kongo sand, and glass fiber.

The amount of the inorganic filler added is about 1 to 80 parts by weight with respect to 100 parts by weight of the ionizing radiation curable resin.

In the lamination of each layer, for example, a pattern layer (solid ink layer, pattern ink layer) is formed by printing on one surface of the base sheet in order, and then a two-component curable urethane resin or the like is adhered on the pattern layer for dry lamination. This can be done by laminating a transparent resin layer with an agent by a dry lamination method, a T-die extrusion method, or the like, and further forming a surface protective layer.

An uneven pattern may be formed by embossing from the surface protective layer side. The uneven pattern can be formed by heat pressing, hairline processing, or the like. Examples of the uneven pattern include a conduit groove, a stone plate surface unevenness, a cloth surface texture, a satin finish, a grain, a hairline, and a perforated groove.

The decorative sheet may have a synthetic resin layer (so-called backer layer) having a thickness of 100 μm or more in the lowermost layer (layer that adheres to the wood base material). The backer layer means a cushioning layer for the purpose of shock absorption or the like in a floor decorative material. Examples of the material constituting the backer layer include polypropylene, ethylene-vinyl alcohol copolymer, polyimide, polymethylpentene, polyethylene terephthalate, and highly heat-resistant polyalkylene terephthalate [for example, a part of ethylene glycol is 1,4-. Polyethylene terephthalate substituted with cyclohexanedimethanol, diethylene glycol, etc., so-called trade name PET-G (manufactured by Eastman Chemical Company)], polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, polycarbonate, poly Examples thereof include allylate, polyimide, polystyrene, polyamide and ABS. These resins can be used alone or in combination of two or more. The upper limit of the thickness of the backer layer is not limited, but 600 μm is suitable.

A known adhesive can be used when laminating the decorative sheet on a wood substrate. As the adhesive, for example, polyvinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ionomer, butadiene / acrylic nitrile rubber, neoprene rubber, natural rubber and the like are used as active ingredients. Adhesive to be used. The thickness of the adhesive layer is not limited, but is preferably about 0.1 to 50 μm.
(Moisture-proof film)
The moisture-proof film is provided on the back surface of the wood substrate. In the present invention, the moisture-proof film, the temperature 40 ° C., the moisture permeability humidity 90% used the following 7g ^{/ m} 2 · 24 hours. Moisture permeability among them preferably has the following 5g ^{/ m} 2 · 24 hours.

The moisture-proof film is not limited as long as it satisfies the above moisture permeability, and for example, synthetic resin films such as olefin-based thermoplastic resins such as polyethylene and polypropylene, and ester-based thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate can be used. Can be used. Among these, those having at least a synthetic resin base material layer and a thin-film deposition layer are particularly preferable. Hereinafter, this embodiment will be described as an example.

As the base material layer made of synthetic resin, olefin-based thermoplastic resins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl alcohol copolymer, and a mixture thereof; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, Ester-based thermoplastic resins such as polyethylene naphthalate-isophthalate copolymer, polycarbonate, polyarylate; acrylic thermoplastic resins such as methyl polymethacrylate, ethyl polymethacrylate, butyl polyacrylate; polyimide, polyurethane, Examples thereof include non-halogen thermoplastic resins such as polystyrene and acrylonitrile-butadiene-styrene resin.

The synthetic resin base material layer may be a sheet stretched in the uniaxial or biaxial direction, or may be unstretched. The synthetic resin base material layer is preferably further laminated with a thin-film deposition layer, and is biaxially oriented because of its position as a base material on which the thin-film deposition layer is formed, strong mechanical strength, and excellent dimensional stability. A sheet stretched to 3 is preferable. The appropriate thickness of the synthetic resin base material layer is approximately 9 to 25 μm.

Examples of the vapor-deposited layer include an inorganic vapor-deposited layer made of a metal thin film represented by aluminum, and an inorganic oxide-deposited layer made of an inorganic oxide thin film represented by silicon oxide, magnesium oxide, and aluminum oxide. The thin-film deposition layer is formed on a synthetic resin base material layer by a well-known thin-film deposition method such as a vacuum vapor deposition method or a plasma activation chemical reaction vapor deposition method. More preferably, it is an inorganic oxide-deposited layer in which the vapor-deposited layer is transparent.

A surface coat layer may be provided on the vapor-deposited layer for the purpose of further improving the gas barrier property of the vapor-deposited layer. Examples of the surface coating layer include polyvinyl alcohol-based resins. In addition, the general formula R ¹ _n M (OR ² ) _m (where R ¹ and R ² represent organic groups having 1 to 8 carbon atoms, M represents a metal atom, and n represents an integer of 0 or more. It contains at least one alkoxide represented by (m represents an integer of 1 or more and n + m represents the valence of M), and a polyvinyl alcohol-based resin and / or an ethylene / vinyl alcohol copolymer. Further, a composition prepared by polycondensation by a sol-gel method in the presence of a sol-gel method catalyst, an acid, water and an organic solvent can be mentioned. Further, by combining polyvinyl alcohol and an ethylene / vinyl alcohol copolymer, gas barrier property, water resistance, weather resistance and the like are remarkably improved. A silane coupling agent or the like may be added to the above composition. A surface coating layer can be obtained by applying these resins or compositions onto the thin-film deposition layer by a well-known coating method such as a roll coating method or a gravure coating method. The surface coat layer also functions as a protective layer for the thin-film deposition layer, and its thickness is preferably about 1 to 10 μm.

The synthetic resin base material layer and / or the surface coat layer can be subjected to surface treatment such as corona treatment, if necessary. By such a surface treatment, the adhesive strength with the adjacent layer can be further increased.

In the present invention, a primer layer may be further provided between the synthetic resin base material layer and the vapor deposition layer, and on one or both sides of the moisture-proof film. Therefore, a preferred embodiment of the moisture-proof film is, for example, a "synthetic resin base material layer / primer layer / thin-film deposition layer / surface coat layer", and further, a primer layer is provided on one side or both sides of the moisture-proof film. It may be an embodiment.

These primer layers are provided in order to enhance the adhesion between the synthetic resin base material layer and the vapor-deposited layer, and to enhance the adhesion when the moisture-proof film is laminated on another layer.

Examples of the resin used for such a primer layer include ester-based resins, urethane-based resins, acrylic-based resins, polycarbonate-based resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral-based resins, and nitrocellulose-based resins. These resins can be used alone or in admixture. The primer layer can be formed by using an appropriate coating means such as a roll coating method or a gravure printing method.

Among these, the primer layer is preferably formed from (i) a copolymer of an acrylic resin and a urethane resin and (ii) isocyanate. That is, the copolymer of the acrylic resin and the urethane resin of (i) has an acrylic polymer component (component A) having a hydroxyl group at the terminal, a polyester polyol component (component B) having a hydroxyl group at both ends, and a diisocyanate component (component). It is obtained by blending C) and reacting to form a prepolymer, and further adding a chain extender (component D) such as diamine to the prepolymer to extend the chain. By this reaction, polyester urethane is formed and an acrylic polymer component is introduced into the molecule to form an acrylic-polyester urethane copolymer having a hydroxyl group at the terminal. The hydroxyl group at the end of this acrylic-polyester urethane copolymer is reacted with the isocyanate of (ii) and cured to form it.

As the component A, a linear acrylic acid ester polymer having a hydroxyl group at the terminal is used. Specifically, linear polymethylmethacrylate (PMMA) having a hydroxyl group at the terminal is preferable because it has excellent weather resistance (particularly, characteristics against photodegradation) and can be easily copolymerized with urethane. The component A is an acrylic resin component in the copolymer, and those having a molecular weight of 5000 to 7000 (weight average molecular weight) are preferably used because they have particularly good weather resistance and adhesiveness. Further, as the component A, only those having hydroxyl groups at both ends may be used, but those having a conjugated double bond at one end may be mixed with the above-mentioned one having hydroxyl groups at both ends. May be good.

The component B reacts with diisocyanate to form polyester urethane, and constitutes a urethane resin component in the copolymer. As the component B, a polyester diol having hydroxyl groups at both ends is used. The polyester diol is composed of an addition reaction product of a diol compound having an aromatic or spiro ring skeleton and a lactone compound or a derivative thereof, or an epoxy compound, a condensation product of a dibasic acid and a diol, and a cyclic ester compound. Induced polyester compounds and the like can be mentioned. Examples of the diol include short-chain diols such as ethylene glycol, propylene glycol, diethylene glycol, butanediol, hexanediol, and methylpentenediol; and alicyclic short-chain diols such as 1,4-cyclohexanedimethanol. it can. Examples of the dibasic acid include adipic acid, phthalic acid, isophthalic acid, and terephthalic acid. The polyester polyol is preferably adipic acid or a mixture of adipic acid and terephthalic acid as the acid component, particularly adipic acid, and an adipate system using 3-methylpentenediol and 1,4-cyclohexanedimethanol as the diol component. It is polyester.

In the primer layer, the urethane resin component formed by the reaction of the component B and the component C gives flexibility to the primer layer and contributes to improvement of adhesiveness. In addition, the acrylic resin component composed of the acrylic polymer contributes to weather resistance and blocking resistance in the primer layer. In the urethane resin, the molecular weight of the component B may be within the range in which a urethane resin capable of sufficiently exhibiting flexibility in the primer layer can be obtained, and adipic acid or a mixture of adipic acid and terephthalic acid and 3-methylpentanediol are used. In the case of a polyester diol composed of 1,4-cyclohexanedimethanol, 500 to 5000 (weight average molecular weight) is preferable.

As the component C, an aliphatic or alicyclic diisocyanate compound having two isocyanate groups in one molecule is used. Examples of this diisocyanate include tetramethylene diisocyanate, 2,2,4 (2,4,4) -1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4'-cyclohexyl. Diisocyanate and the like can be mentioned. As the diisocyanate component, isophorone diisocyanate is preferable in terms of physical properties and cost. The equivalent ratio of the isocyanate group to the total hydroxyl group (which may be an amino group) of the acrylic polymer, polyester polyol, and chain extender described later when reacting the above components A to C is such that the isocyanate group is excessive. To.

When the above three components A, B, and C are reacted at 60 to 120 ° C. for about 2 to 10 hours, the isocyanate group of the diisocyanate reacts with the hydroxyl group at the terminal of the polyester polyol to form a polyester urethane resin component and an acrylic polymer. A compound in which diisocyanate is added to the terminal hydroxyl group is also mixed, and a prepolymer in a state where excess isocyanate groups and hydroxyl groups remain is formed. As a chain extender, for example, diamines such as isophoronediamine and hexamethylenediamine are added to this prepolymer to react the isocyanate group with the chain extender, and the chain is extended so that the acrylic polymer component is contained in the polyester urethane molecule. The acrylic-polyester urethane copolymer of (i) which is introduced and has a hydroxyl group at the terminal can be obtained.

Add the isocyanate of (ii) to the acrylic-polyester urethane copolymer of (i), and adjust the viscosity to the required viscosity in consideration of the coating method and the coating amount after drying. The primer layer may be formed by applying by a well-known coating method such as a coating method. Further, the isocyanate of (ii) may be any as long as it can react with the hydroxyl group of the acrylic-polyester urethane copolymer of (i) and be cross-cured, for example, an aliphatic or aromatic divalent or higher. Group isocyanates can be used, and aliphatic isocyanates are particularly desirable from the viewpoint of preventing thermal discoloration and weather resistance. Specifically, tolylene diisocyanate, xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate monomer, multimers such as dimers and trimers of these, or these. Examples thereof include polyisocyanates such as derivatives (adducts) in which the isocyanate of the above is added to a polyol.

As the coating amount after drying of the primer layer is from 1 to 20 g / ^{m 2,} preferably from 1 to 5 g / ^{m 2.} Further, the primer layer may be a layer to which an additive such as a filler such as silica powder, a light stabilizer, or a colorant is added, if necessary.

A known adhesive can be used when laminating the moisture-proof sheet on a wood substrate. As the adhesive, for example, polyvinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ionomer, butadiene / acrylic nitrile rubber, neoprene rubber, natural rubber and the like are used as active ingredients. Adhesive to be used. The thickness of the adhesive layer is not limited, but is preferably about 0.1 to 50 μm.

Floor decorative material of the present invention, moisture permeability by having a moisture-resistant films is less than 7g / m 2 · ²⁴ hours, moisture permeability of the back surface wood substrate is kept low. Therefore, even when a decorative sheet having low moisture permeability is laminated on the front surface of a wood base material using a Lauan alternative material having a dimensional change amount of more than 0.02% per 1% water content change, the wood base is used. Since the moisture permeability of the front surface and the back surface of the material can be set to the same level, the occurrence of warping and bending of the floor decorative material is sufficiently suppressed. Such a floor decorative material of the present invention is suitable as a floor decorative material to be applied to the floor surface of various buildings and a floor decorative material used for floor heating as a special purpose.

It is a schematic diagram (one example) of the decorative material for a floor of this invention. It is a schematic diagram which shows the warp and the tow bending of a decorative material for a floor. It is a figure which shows the sample used for measuring the average moisture content and the moisture content difference of a wood base material. It is a schematic diagram of the floor heating system test standard II.

1. 1. Decorative sheet 2. Adhesive layer 3. Wood base material (Lauan alternative material)
4. Adhesive layer 5. Moisture proof film

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Example 1
(1) A decorative sheet (0.4 mm) containing a synthetic resin layer is coated with an adhesive (BA-10L / BA-11B, 9 g / scale) manufactured by Chuo Rika Kogyo to a 5.5 mm thick MDF (wooden base material). I stuck it on the front side. The dimensional change rate per 1% water content change of the MDF was 0.05%. The scale angle indicates the area of a plane represented by 303 mm in length × 303 mm in width (the same applies hereinafter).
(2) A moisture-proof film was attached to the back surface of the MDF using an adhesive (BA-10L / BA-11B, 9 g / shaku angle) manufactured by Chuo Rika Kogyo. The laminated body in this state is called a decorative board.
(3) The decorative board was cut with a gang saw to a size of 313 mm in length × 1840 mm in width.
(4) Further, a tenona processing machine was used to perform sane processing, end chamfering processing, and V-groove processing (V-groove processing width is 1.5 mm width).
(5) Further, a paint was applied to the sane processed portion, the end chamfered portion and the V-groove processed portion on the coating line (paint: a paint containing a two-component curable urethane resin).

A floor decorative material was produced through the above steps.

The moisture-proof film was prepared as follows. That is, a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm was prepared, and a primer layer made of a two-component curable urethane resin was provided on one side. Further, an aluminum vapor deposition layer was provided on the primer layer. The film thus obtained is referred to as a "deposited PET film".

^{0.2 g / m 2} (dry state) of a PVA / silicate-based surface coat layer is formed on the vapor-deposited PET film, and a laminate (synthetic resin base material layer (PET) / vapor-deposited layer / surface coat layer) is formed. Was produced. After corona discharge treatment on both sides of the laminate, a two-component curable resin in which a curing agent (isocyanate) was added to a main agent (a mixture of urethane resin and nitrocellulose resin) was used as a solid content of 5 g each by a gravure printing method. It was applied at a coating amount of / m ² to form an adhesive primer layer on both sides. This gave moistureproof film (moisture permeability 1g ^{/ m} 2 · 24 hours).

Example 2
A floor decorative material was prepared in the same manner as in Example 1 except that a particle board having a thickness of 9 mm (the dimensional change rate per 1% change in water content was 0.049%) was used as the wood base material.

Example 3
A floor decorative material was prepared in the same manner as in Example 1 except that a 12 mm thick softwood plywood (radiata pine, dimensional change rate per 1% water content change was 0.026%) was used as a wood base material.

Example 4
Except for using the PE (polyethylene sheet. Moisture permeability 7g / m 2 · ²⁴ hours) as a moisture film in the same manner as in Example 1 to prepare a floor decorative material.

Comparative Example 1
A floor decorative material was produced in the same manner as in Example 1 except that a moisture-proof film was not used.

Comparative Example 2
A floor decorative material was produced in the same manner as in Example 2 except that a moisture-proof film was not used.

Comparative Example 3
A floor decorative material was produced in the same manner as in Example 3 except that a moisture-proof film was not used.

Comparative Example 4
Proof paper as a moisture film was prepared except for using (polyethylene as a core layer, both sides of those that have been stacked in the paper. Moisture permeability 10g / m 2 · ²⁴ hours) in the same manner as in Example 1 for floors decorative material ..

Conventional example 1
A floor decorative material was prepared in the same manner as in Example 1 except that a 12 mm thick Lauan plywood (dimension change rate per 1% water content change was 0.016%) was used as a wood base material and a moisture-proof film was not used. did.

Test Example 1 (warp and tow in an atmosphere of 40 ° C)
The floor decorative materials prepared in Examples 1 to 4, Comparative Examples 1 to 4, and Conventional Example 1 were left in a 40 ° C. atmosphere (dry atmosphere) (7 days), and the amount of warpage and the amount of bending of the floor decorative material. Was measured.

A schematic diagram of the amount of warpage and the amount of towing is shown in FIG. The amount of warpage and the amount of towing were measured with a feeler gauge. If the amount of warpage is 20 mm / 1840 mm (the amount of warpage with respect to the horizontal length) or less, it is acceptable (suitable for practical use). In addition, a pass (suitable for practical use) is a result of a pulling bend amount of 0.3 mm / 1840 mm (a pulling bend amount with respect to the horizontal length) or less. The results are shown in Table 1.

Test Example 2 (warp and tow in a 90% RH atmosphere at 40 ° C)
The floor cosmetics prepared in Examples and Comparative Examples were left in a 90% RH atmosphere at 40 ° C. (7 days), and the amount of warpage and the amount of bending of the floor cosmetics were measured in the same manner as in Test Example 1. .. The results are shown in Table 1.

As apparent from the results shown in Tables 1, floor decorative material of the present invention that the moisture permeability is provided moisture barrier film is less than 7g / m 2 · ²⁴ hours, the dimensions due to humidity of the wood substrate by the presence of the moisture-resistant films Change is effectively suppressed. As a result, warping and towing of the floor decorative material are prevented, and the result is closer to the test result of Conventional Example 1 (using Lauan plywood).

Example 5
(1) floor for decorative sheet: a (0.16 mm thick, the moisture permeability 3g / m ² · 24 hours), 12 mm thick with a central Rika made adhesive (BA-10L / BA-11B , 9g / scale angle) It was attached to the front surface of the particle board (PB) (wooden base material) of. The dimensional change rate per 1% water content change of the PB was 0.045%, and the average water content was 6.5% by weight.
(2) to the back surface of the PB, the central Rika made adhesive (BA-10L / BA-11B , 9g / scale angle) using a moisture-proof film (PET film + deposition layer, moisture permeability: 3g / m ² · 24 hours ) Was pasted together. The laminated body in this state is called a decorative board.
(3) The decorative board was cut with a gang saw to a size of 313 mm in length × 1840 mm in width.
(4) Further, a tenona processing machine was used to perform sane processing, end chamfering processing, and V-groove processing (V-groove processing width is 1.5 mm width).
(5) Further, a paint was applied to the sane processed portion, the end chamfered portion and the V-groove processed portion on the coating line (paint: a paint containing a two-component curable urethane resin).

A floor decorative material was produced through the above steps. Between each step, the decorative board was wrapped with a PP film (30 μm thickness, moisture permeability 15 g) to prevent moisture.

Example 6
A floor decorative material was produced in the same manner as in Example 5, except that the moisture-proof treatment using a PP film was not performed between the steps. As a result, the moisture content of the peripheral part of the wood base material was made higher than that of the central part.

Example 7
A floor decorative material was produced in the same manner as in Example 5, except that a PB base material having a water content of 2% higher in the central portion of the wood base material than that in the peripheral portion was used.

Example 8
A floor decorative material was prepared in the same manner as in Example 5, except that a softwood plywood having a water content of 1.7% higher in the central portion of the wood base material was used than in the peripheral portion.

Comparative Example 5
A floor decorative material was prepared in the same manner as in Example 6 except that PB having an average moisture content of 5.5% was used as the wood base material.

Comparative Example 6
A floor decorative material was prepared in the same manner as in Example 6 except that the floor cosmetic material was left for one week without moisture-proof treatment after the tenona processing.

Comparative Example 7
A floor decorative material was produced in the same manner as in Example 5, except that a PB base material having a water content of 2.5% higher in the central portion of the wood was used.

Comparative Example 8
A floor decorative material was prepared in the same manner as in Example 5, except that the average moisture content was adjusted to 10.5% and a PB base material having a moisture content in the central portion of the wood was 1.3% lower than that in the peripheral portion was used.

Test Example 3 (Towing and bending after cutting the floor decorative material and evaluation of construction suitability)
<Evaluation of the amount of bending after cutting>
The floor decorative materials (length 313 mm × width 1840 mm) prepared in Examples 5 to 8 and Comparative Examples 5 to 8 were cut into about half (length 150 mm × width 1840 mm) at the central portion.

The amount of lateral bending of the cut flooring material was measured using a straightedge and a feeler gauge. The measurement was performed within 30 minutes after cutting. The amount of pulling and bending is indicated by + when each sane side (male sane, female sane) is convex.

The amount of bending after cutting is allowed as long as it is in the range of "-1.0 mm / width 1840 mm to + 0.7 mm / width 1840 mm".
<Construction aptitude evaluation>
The floor decorative materials (length 313 mm × width 1840 mm) prepared in Examples 5 to 8 and Comparative Examples 5 to 8 were first applied in the same size. Then, the floor decorative material cut in about half (length 150 mm × width 1840 mm) at the center was applied within 30 minutes after cutting, and the construction suitability after cutting was evaluated. The evaluation criteria were as follows.

◯: As with before cutting, construction can be performed without problems, and no gaps are found at the seams.

Δ: It can be constructed with some effort, and no gap is found at the seam.

X: Construction is difficult, and a gap exceeding 0.3 mm is observed at the seam.

Test Example 4 (Floor heating system test)
The floor decorative materials (length 313 mm × width 1840 mm) prepared in Examples 5 to 8 and Comparative Examples 5 to 8 were subjected to a floor heating system test. Underfloor heating systems are generally not installed in the corners of the room (near walls or around pillars), but in the center of the room except for the corners. Therefore, in Test Example 4, a floor heating system test was conducted on a floor decorative material (length 313 mm × width 1840 mm).

Specifically, the floor heating system test shown in Fig. 4 (finishing material / base material "II. Durability performance thermal durability test" 80 ° C hot water x 1100 is used as a test piece made by assembling floor decorative materials. It was used for continuous hot water flow for hours and a unified standard system for gas companies).

About the test piece after the test
(1) Pass if the clearance displacement amount of the sane assembly part (fitting part) is 0.5 mm or less (2) Pass if the step displacement amount of the sane assembly part (fitting part) is 0.5 mm or less (3) Horizontal If the amount of warpage (= width warp) in the direction (1840 mm) was less than 1 mm, evaluation was performed according to the acceptance criteria. All passed and marked with ○, and those with requirements that did not meet even one were marked with ×.

The results of each evaluation / test are shown in Table 2 below.

As is clear from the results in Table 2 above, the average water content is 6 to 10% by weight, and the water content in the central part is in the range of -1% to + 2% as compared with the water content in the peripheral part. By using a wood base material, it is possible to effectively suppress the towing and bending after cutting. Moreover, floor decorative material of the present invention, the moisture permeability of the moisture-proof film is not more than 7g / m 2 · ²⁴ hours, can be subjected to practical use as a floor heating flooring.

Claims (4)

A decorative sheet having at least one thermoplastic resin layer from the front surface to the back surface, the amount of dimensional change per 1% moisture content change is larger than 0.02%, and the average moisture content is 6 to 10% by weight. The moisture-proof film used for a floor decorative material having a laminated structure including a wood base material and a moisture-proof film, wherein the moisture-proof film is
Moisture permeability is less than or equal to 1g ^{/ m} 2 · 24 hours,
At least selected from the group consisting of ester resin, urethane resin, acrylic resin, polycarbonate resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, and nitrocellulose resin on one side of the thermoplastic resin film. It is a laminate having a primer layer and an aluminum vapor deposition layer made of one kind in this order.
Moisture-proof film characterized by that. The moisture-proof film according to claim 1, wherein the laminate includes the primer layer, the aluminum vapor deposition layer, and the surface coat layer on one side of the thermoplastic resin film in that order. The moisture-proof according to claim 1 or 2, wherein the laminate further includes an adhesive primer layer made of a two-component curable resin containing a main agent containing a urethane resin and a curing agent containing an isocyanate on one or both sides. the film. The moisture-proof film according to claim 3, wherein the main agent is a mixture of the urethane resin and a nitrified cotton-based resin.

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