JP2023169240A - Laminate of moisture-proof film and wooden base material - Google Patents

Abstract

To provide a laminate of a moisture-proof film and a wooden base material used for a decorative material for a floor having a reduced occurrence of curving and warping even when a decorative sheet with a low moisture permeability is laminated on a front surface of the wooden base material.SOLUTION: A laminate A of a moisture-proof film and a wooden base material used for a decorative material for a floor is formed by laminating a decorative sheet 1, a wooden base material 3 and a moisture-proof film 5 from a front surface to a rear surface, and in the laminate A, (1) the moisture-proof film has a moisture permeability equal to or less than 1 g/m2 24 hours and is a laminate B comprising a primer layer consisting of a two-part curing type urethane resin, an aluminium vapor deposition layer and a surface coat layer containing a polyvinyl alcohol resin in this order on a single surface of a thermoplastic resin film, and (2) the wooden base material has a dimension variation per 1% moisture content variation greater than 0.02% and has an average moisture content rate of 6-10 wt.%.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a decorative floor material that is suppressed from warping and bending.

Conventionally, wood-based decorative boards used as decorative materials for the floors of houses have been made by applying a natural wood design to the top surface of a wood base material obtained from high-quality logs (for example, hardwood lauan plywood) through an adhesive. It is known that a decorative sheet is attached.

As a wood base material, the above-mentioned broad-leaved tree lauan is often used, but in recent years, raw wood has become difficult to obtain due to the scarcity of natural resources, restrictions on logging, etc., and the shortage of the material has progressed. This problem is particularly serious for hardwoods such as lauan. Therefore, progress is being made in the development of wood base materials that can be used in place of lauan plywood. Examples of alternative materials for lauan include softwood plywood, wood boards made by molding and solidifying wood fibers or wood pieces separated from wood waste with adhesive (e.g., medium density wood fiberboard (MDF), high density wood fiberboard). : HDF, particle board: PB), and fast-growing plywood made of fast-growing trees.

However, these lauan substitute materials have a problem in that the amount of dimensional change per 1% change in moisture 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 dimensional change per 1% moisture content of lauan plywood is 0.015 to 0.02%, while for MDF and PB it is about 0.045%, and for softwood plywood (e.g. radiata pine) it is 0.015% to 0.02%. It is about .025%. Therefore, the lauan substitute material has the characteristic that it tends to warp or bend (deviate from the perpendicularity of the floor surface) due to changes in humidity.

In order to improve the above problem, it has been proposed to laminate a moisture-proof sheet on the back side of the lauan alternative material (for example, Patent Documents 1 to 3). However, the moisture-proof sheets described in Patent Documents 1 to 3 have a moisture permeability of about 20 g/m ² ·24 hours at most, and their performance is insufficient to prevent warping and bending of the lauan substitute material. Particularly in recent years, decorative sheets with low moisture permeability (2 g/m ^2.24 hours or less) are often laminated on the front side of lauan alternative materials, so the moisture permeability of the back side is equal to or higher than that of the front side. It is required to reduce moisture permeability.

From the above, even if a lauan substitute material with a dimensional change of more than 0.02% per 1% change in moisture content is used as a wood base material and a decorative sheet with low moisture permeability is laminated on the front surface, It is desired to develop a decorative material for floors that suppresses the occurrence of warping and bending.

Japanese Patent Application Publication No. 2001-193267 Japanese Patent Application Publication No. 2001-260109 JP2006-097321A

The present invention uses a lauan alternative material with a dimensional change of more than 0.02% per 1% change in moisture content as a wood base material, and even when a decorative sheet with low moisture permeability is laminated on the front surface. An object of the present invention is to provide a decorative material for floors in which the occurrence of warping and bending is suppressed.

As a result of extensive research, the present inventors have discovered that the above object can be achieved when using a specific moisture-proof film, and have completed the present invention.

That is, the present invention relates to the following laminate of a moisture-proof film and a wood base material.
1. A laminate A of the moisture-proof film and the wood base material used for a decorative floor material having a laminated structure comprising a decorative sheet, a wood base material, and a moisture-proof film from the front surface to the back surface,
(1) The moisture-proof film is
Moisture permeability is 1 g/m ^2.24 hours or less,
A laminate B comprising a primer layer made of a two-component curable urethane resin, an aluminum vapor deposited layer, and a surface coat layer containing a polyvinyl alcohol resin on one side of a thermoplastic resin film, in that order,
(2) The wood base material has a dimensional change per 1% change in moisture content of more than 0.02%, and an average moisture content of 6 to 10% by weight.
A laminate A of a moisture-proof film and a wood base material, characterized by:
2. The moisture-proof film according to item 1, wherein the laminate B further includes an adhesive primer layer made of a two-component curable resin containing a main resin containing a urethane resin and a curing agent containing an isocyanate on one or both sides. and a wood base material.
3. Laminated body A of a moisture-proof film and a wood base material according to item 2 above, wherein the main ingredient is a mixture of the urethane resin and a nitrified cotton resin.

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

The decorative floor material of the present invention is a decorative floor material in which a decorative sheet is laminated on the front surface of a wooden base material, and a moisture-proof film is laminated on the back surface of the wooden base material,
(1) The wood base material has a dimensional change of more than 0.02% per 1% change in moisture content, and (2) the moisture-proof film has a moisture permeability of 7 g/m ^2.24 hours or less. It is characterized by Note that the moisture permeability is a value measured under an environment of a temperature of 40°C and a humidity of 90% RH according to JIS Z0208 (moisture permeability test method (cup method)). Hereinafter, moisture permeability in this specification indicates a value measured under the conditions.

The floor decorative material of the present invention having the above-mentioned characteristics has a moisture-proof film having a moisture permeability of 7 g/m ² ·24 hours or less, thereby suppressing the moisture permeability of the back surface of the wooden base material to a low level. Therefore, even if a decorative sheet with low moisture permeability is laminated on the front surface of a lauan substitute material with a dimensional change of more than 0.02% per 1% change in moisture content as a wood base material, Since the moisture permeability of the front and back surfaces of the material can be set to the same level, the occurrence of warping and bending of the decorative floor material is sufficiently suppressed. The decorative floor material of the present invention is suitable as a decorative floor material applied to the floors of various buildings, and as a special purpose decorative material for floors used in floor heating applications.

Hereinafter, each structure of the floor decorative material of the present invention will be explained.
(wood base material)
As the wood base material of the present invention, a lauan alternative material is used. In other words, it is a material that can replace conventional lauan plywood, etc., and includes at least one of medium-density wood fiberboard (MDF), high-density wood fiberboard (HDF), particle board (PB), softwood plywood, fast-wood plywood, etc. Use seeds. Examples of fast-growing trees include poplar, falcata, acacia, chameleon, eucalyptus, terminaria, and the like. These lauan replacement materials have a dimensional change of greater than 0.02% per 1% change in moisture content.

In this specification, "the amount of dimensional change per 1% moisture content" is the amount of dimensional change measured by the following procedure.
(1) Prepare a test piece of wood base material cut to 300 mm x 303 mm.
(2) Measure the current dimensions (lengths of the four sides) of the test piece using a caliper in a normal temperature (25°C) environment. (3) Leave the test piece in a 40°C oven (humidity-free, dry atmosphere≒0%) for one week.
(4) After one week, measure the weight and dimensions (length of four sides) of the test piece.
(5) Measure the dimensional change rate per 1% moisture 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 wooden base material has an average moisture content of 6 to 10% by weight, and the moisture content of the central part is lower than that of the peripheral part, in preparation for the case where the decorative flooring material is cut and used according to the construction site. It is preferable to use a wood base material whose moisture content is in the range of -1% to +2%. If the size of the wood base material is, for example, about 150 mm long x 1840 mm wide (especially the short side length is 200 mm or less), the wood base material may warp or bend due to uneven moisture content in the center and periphery. becomes more likely to occur. Therefore, by setting the moisture content characteristics of the wood base material to the above conditions, it is possible to suppress the occurrence of warping and bending even when the decorative floor material is cut and used. In addition, when cutting and using the floor decorative material, specifically, it is assumed that the floor decorative material is applied to a corner part of the room (along a wall or around a pillar).

The average moisture content of the wood base material is preferably 6 to 10% by weight, more preferably 6.5 to 8% by weight. If the average moisture content is within the above range, it is easy to suppress the occurrence of bending or warping after cutting. Among these, when the decorative floor material is used for floor heating, it is preferable to set the average moisture content to 6 to 9% by weight.

The moisture content of the wood base material is preferably in the range of -1% to +2%, and preferably in the range of -0.5% to +1%, compared to the moisture content in the peripheral area. is more preferable. In addition, the peripheral part of the wooden base material means the area of 5 cm around the wooden base material, and the central part of the wooden base material means the inside of the wooden base material excluding the said peripheral part.

In addition, the average moisture content and moisture content difference (hereinafter, "moisture content difference" refers to the moisture content difference between the peripheral part and the central part of the wood base material) of the wood base material in this specification are measured using the following procedure. is the value to be used.
(A) As shown in FIG. 3, a wooden base material measuring 303 mm in length x 1818 mm in width is prepared.
(B) The area within 5 cm from the periphery of the wood base material is defined as the peripheral area, and the area inside this area is defined as the central area. As shown by numbers 1 to 35 in FIG. 3, 35 samples of 5 cm x 5 cm are taken evenly, and the moisture content is measured by the total drying method. The total dry method is a method in which each sample is left in an oven at 105° C. for 3 days, and then the moisture content of each sample is measured using the following calculation formula. The time before being left is called before treatment, and the time after being left is called after treatment.

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

Base sheets include 1) paper such as thin paper, high-quality paper, kraft paper, Japanese paper, titanium paper, resin-impregnated paper, paper-reinforced paper, 2) wood fiber, glass fiber, asbestos, polyester fiber, vinylon fiber, rayon. Examples include laminates of one or more of woven fabrics or nonwoven fabrics made of fibers, etc., and 3) sheets made of synthetic resins such as polyolefin, polyester, polyacrylic, polyamide, polyurethane, and polystyrene.

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, or ozone treatment.

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

The ink used for the pattern layer includes, as a vehicle, chlorinated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, polyester, polyurethane consisting of isocyanate and polyol, polyacrylic, polyvinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate, etc. It is possible to use one or a mixture of two or more of polymers, cellulose resins, polyamide resins, etc., and then add pigments, solvents, various auxiliary agents, etc. to form an ink. Among these, one type or a mixture of two or more types of resins such as polyester, polyurethane consisting of isocyanate and polyol, polyacrylic, polyamide resin, etc. are preferable from the viewpoint of environmental issues, adhesion to the printing surface, etc.

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

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

The transparent resin layer may be colored. In this case, a coloring agent may be added to the thermoplastic resin. As the coloring agent, pigments or dyes used in the pattern layer can be used.

The transparent resin layer contains fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, radical scavengers, and soft components (e.g., rubber). Various additives such as these may also be included.

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

Examples of thermosetting resins include unsaturated polyester resins, polyurethane resins (including two-component curing polyurethanes), epoxy resins, aminoalkyd resins, phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, and melamine. - Examples include urea cocondensation resins, silicone resins, and polysiloxane resins.

A crosslinking agent, a curing agent such as a polymerization initiator, and a polymerization accelerator can be added to the resin. For example, as curing agents, isocyanates, organic sulfonates, etc. can be added to unsaturated polyester resins, polyurethane resins, etc., organic amines, etc. can be added to epoxy resins, peroxides such as methyl ethyl ketone peroxide, azoisobutyl nitrile, etc. Radical initiators can be added to unsaturated polyester resins.

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

The ionizing radiation-curable resin is not limited as long as it undergoes a crosslinking polymerization reaction upon 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 epoxy group in the molecule that can be crosslinked by irradiation with ionizing radiation can be used. Examples include acrylate resins such as urethane acrylate, polyester acrylate, and epoxy acrylate; silicon resins such as siloxane; polyester resins; and epoxy resins.

Ionizing radiation includes visible light, ultraviolet rays (near ultraviolet rays, vacuum ultraviolet rays, etc.), X-rays, electron beams, ion beams, etc. Among these, ultraviolet rays and electron beams are preferred.

As the ultraviolet light source, a light source such as 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 approximately 190 to 380 nm.

As the electron beam source, various electron beam accelerators such as Cockcroftwald type, Vandegraft type, resonant 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 amount of electron beam irradiation is preferably about 2 to 15 Mrad.

Ionizing radiation-curable resins are sufficiently cured by irradiation with electron beams, but when curing by irradiation 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, photopolymerization initiators include, for example, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, Michler benzoyl benzoate, Michler ketone, diphenyl sulfide, dibenzyl disulfide. , diethyl oxide, triphenylbiimidazole, and isopropyl-N,N-dimethylaminobenzoate. In addition, in the case of a resin system having a cationic polymerizable functional group, for example, at least one of aromatic diazonium salts, aromatic sulfonium salts, metallocene compounds, benzoin sulfonic acid esters, freeloxysulfoxonium diallylodosyl salts, etc. 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 per 100 parts by weight of the ionizing radiation curable resin.

As a method for forming the protective layer using an 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 coating amount of the solution is approximately 5 to 30 μm in terms of solid content, preferably about 5 to 20 μm.

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

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

Lamination of each layer is performed, for example, by sequentially printing a pattern layer (solid ink layer, pattern ink layer) on one side of the base sheet, and then applying a known dry lamination adhesive such as a two-component curable urethane resin onto the pattern layer. This can be carried out by laminating transparent resin layers via a dry lamination method, T-die extrusion method, etc. via an agent, and then 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, etc. Examples of the uneven pattern include conduit grooves, stone plate surface unevenness, cloth surface texture, satin finish, grain, hairline, parallel grooves, and the like.

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

When laminating the above-mentioned decorative sheet on a wood base material, a known adhesive can be used. Examples of adhesives include polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ionomer, butadiene/acrylonitrile rubber, neoprene rubber, natural rubber, etc. as active ingredients. Examples include adhesives that can be used. Although the thickness of the adhesive layer is not limited, it is preferably about 0.1 to 50 μm.
(moisture-proof film)
The moisture-proof film is provided on the back side of the wood base material. In the present invention, the moisture-proof film used has a moisture permeability of 7 g/m ² ·24 hours or less at a temperature of 40° C. and a humidity of 90%. Among these, those with a moisture permeability of 5 g/m ² ·24 hours or less are preferred.

The moisture-proof film is not limited as long as it satisfies the above-mentioned moisture permeability, and examples thereof include films made of synthetic resins such as olefin thermoplastic resins such as polyethylene and polypropylene, and ester thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Can be used. Among these, those having at least a synthetic resin base material layer and a vapor deposition layer are particularly preferred. This aspect will be explained below by way of example.

For the synthetic resin base layer, olefinic thermoplastic resins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl alcohol copolymer, and mixtures thereof; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, Ester thermoplastic resins such as polyethylene naphthalate-isophthalate copolymer, polycarbonate, and polyarylate; Acrylic thermoplastic resins such as polymethyl methacrylate, polyethyl methacrylate, and polybutyl acrylate; polyimide, polyurethane, Examples include non-halogen thermoplastic resins such as polystyrene and acrylonitrile-butadiene-styrene resin.

The synthetic resin base material layer may be a sheet stretched uniaxially or biaxially, or may be unstretched. It is preferable that the synthetic resin base material layer is further laminated with a vapor deposited layer, and because of its position as a base material on which the vapor deposited layer is formed, it has strong mechanical strength and excellent dimensional stability, so it is preferably formed in two axial directions. Preferably, the sheet is stretched. The thickness of the synthetic resin base layer is approximately 9 to 25 μm.

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

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

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

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 layer/primer layer/evaporation layer/surface coat layer" embodiment, and a primer layer is further provided on one or both sides of the moisture-proof film. It may also be the form.

These primer layers are provided in order to improve the adhesion between the synthetic resin base material layer and the vapor deposited layer, and to improve the adhesion when laminating the moisture-proof film on other layers.

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

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

As the component A, a linear acrylic acid ester polymer having a hydroxyl group at the end is used. Specifically, linear polymethyl methacrylate (PMMA) having a hydroxyl group at the end is preferable because it has excellent weather resistance (especially properties against photodeterioration) and is easy to copolymerize with urethane. The component A is an acrylic resin component in the copolymer, and those having a molecular weight of 5,000 to 7,000 (weight average molecular weight) are preferably used because they have particularly good weather resistance and adhesive properties. In addition, as the component A, a component having a hydroxyl group at both ends may be used alone, but a component with a conjugated double bond remaining at one end may be mixed with the component having a hydroxyl group at both ends. Good too.

The component B reacts with the diisocyanate to form a polyester urethane, and constitutes the urethane resin component in the copolymer. The component B used is a polyester diol having hydroxyl groups at both ends. This polyester diol includes an addition reaction product of a diol compound having an aromatic or spiro ring skeleton and a lactone compound or its derivative, or an epoxy compound, a condensation product of a dibasic acid and a diol, and a cyclic ester compound. Examples include derived polyester compounds. 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. can. Further, examples of dibasic acids include adipic acid, phthalic acid, isophthalic acid, and terephthalic acid. Preferred polyester polyols include 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 improved adhesion. Further, the acrylic resin component made of an 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 a range that provides a urethane resin that can sufficiently exhibit flexibility in the primer layer, and may include adipic acid or a mixture of adipic acid and terephthalic acid, and 3-methylpentanediol. In the case of a polyester diol consisting of 1,4-cyclohexanedimethanol, the weight average molecular weight is preferably 500 to 5000 (weight average molecular weight).

As the component C, an aliphatic or alicyclic diisocyanate compound having two isocyanate groups in one molecule is used. Examples of the diisocyanate include tetramethylene diisocyanate, 2,2,4(2,4,4)-1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4'-cyclohexyl Diisocyanates and the like can be mentioned. As the diisocyanate component, isophorone diisocyanate is preferred in terms of physical properties and cost. When reacting the above components A to C, the equivalent ratio of the total hydroxyl groups (sometimes amino groups) and isocyanate groups of the acrylic polymer, polyester polyol, and chain extender described below is such that the isocyanate groups are in excess. Make it.

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 end of the polyester polyol to form a polyester urethane resin component and an acrylic polymer. A compound in which a diisocyanate is added to the terminal hydroxyl group is also mixed, and a prepolymer with excess isocyanate groups and hydroxyl groups remaining is formed. A diamine such as isophorone diamine or hexamethylene diamine is added to this prepolymer as a chain extender, and the isocyanate group is reacted with the chain extender. By extending the chain, the acrylic polymer component is incorporated into the polyester urethane molecules. The acrylic-polyester urethane copolymer (i) having a hydroxyl group at the end can be obtained.

The isocyanate (ii) is added to the acrylic-polyester urethane copolymer (i), and the coating liquid is adjusted to the required viscosity by considering the coating method and amount of coating after drying. The primer layer may be formed by coating using a well-known coating method such as a coating method. The isocyanate (ii) may be any one that can react with the hydroxyl group of the acrylic-polyester urethane copolymer (i) to crosslink and cure it, such as divalent or higher aliphatic or aromatic Group isocyanates can be used, and aliphatic isocyanates are particularly preferred from the viewpoint of preventing thermal discoloration and weather resistance. Specifically, monomers of tolylene diisocyanate, xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, dimers and trimers of these, or multimers of these. Examples include polyisocyanates such as derivatives (adducts) of isocyanates added to polyols.

The coating amount of the primer layer after drying is 1 to 20 g/m ² , preferably 1 to 5 g/m ² . Further, the primer layer may be a layer to which additives such as a filler such as silica powder, a light stabilizer, and a coloring agent are added, if necessary.

When laminating the above-mentioned moisture-proof sheet on a wooden base material, a known adhesive can be used. Examples of adhesives include polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ionomer, butadiene/acrylonitrile rubber, neoprene rubber, natural rubber, etc. as active ingredients. Examples include adhesives that can be used. Although the thickness of the adhesive layer is not limited, it is preferably about 0.1 to 50 μm.

The floor decorative material of the present invention has a moisture-proof film having a moisture permeability of 7 g/m ² ·24 hours or less, so that the moisture permeability of the back surface of the wood base material is kept low. Therefore, even if a decorative sheet with low moisture permeability is laminated on the front surface of a lauan substitute material with a dimensional change of more than 0.02% per 1% change in moisture content as a wood base material, Since the moisture permeability of the front and back surfaces of the material can be set to the same level, the occurrence of warping and bending of the decorative floor material is sufficiently suppressed. The decorative floor material of the present invention is suitable as a decorative floor material applied to the floors of various buildings, and as a special purpose decorative material for floors used in floor heating applications.

FIG. 1 is a schematic diagram (an example) of a floor decorative material of the present invention. FIG. 3 is a schematic diagram showing warping and bending of a floor decorative material. It is a figure which shows the sample used for the measurement of the average moisture content and moisture content difference of a wood base material. It is a schematic diagram of floor heating system test standard II.

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

The present invention will be explained in more detail by showing Examples and Comparative Examples below. 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 attached to a 5.5 mm thick MDF (wood base material) using Chuo Rika Kogyo adhesive (BA-10L/BA-11B, 9 g/square). It was pasted on the front side. The dimensional change rate per 1% moisture content change of the MDF was 0.05%. Note that the square angle refers to the area of a plane expressed as 303 mm long x 303 mm wide (the same applies hereinafter).
(2) A moisture-proof film was attached to the back side of the MDF using an adhesive manufactured by Chuo Rika Kogyo (BA-10L/BA-11B, 9 g/square). The laminate in this state is called a decorative board.
(3) The decorative board was cut with a gang saw to a size of 313 mm (length) x 1840 mm (width).
(4) Also, using a Tenona processing machine, tongue processing, end chamfering, and V-groove processing (V-groove processing width was 1.5 mm) were performed.
(5) Further, on the painting line, a paint was applied to the grooved part, the end chamfered part, and the V-groove part (paint: a paint containing a two-component curable urethane resin).

A decorative floor material was produced through the above steps.

The moisture-proof film was produced as follows. That is, a biaxially stretched polyethylene terephthalate film with a thickness of 12 μm was prepared, and a primer layer made of a two-component curable urethane resin was provided on one side. Furthermore, an aluminum vapor deposition layer was provided on the primer layer. The film obtained in this way is called a "deposited PET film".

A surface coating layer of 0.2 g/m ² (dry state) made of PVA/silicate system was formed on the vapor-deposited PET film, and a laminate (synthetic resin base material layer (PET)/evaporation layer/surface coating layer) was formed. was created. After subjecting both sides of the laminate to corona discharge treatment, a two-component curing resin in which a curing agent (isocyanate) was added to the base resin (a mixture of urethane resin and nitrified cotton resin) was printed using a gravure printing method, with a solid content of 5 g each. / ^m2 to form adhesive primer layers on both sides. As a result, a moisture-proof film (moisture permeability of 1 g/m ² ·24 hours) was obtained.

Example 2
A decorative floor material was produced in the same manner as in Example 1, except that 9 mm thick particle board (dimensional change rate per 1% moisture content change was 0.049%) was used as the wood base material.

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

Example 4
A decorative floor material was produced in the same manner as in Example 1, except that PE (polyethylene sheet, moisture permeability 7 g/m ² 24 hours) was used as the moisture-proof film.

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

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

Comparative example 3
A decorative floor material was produced in the same manner as in Example 3 except that no moisture-proof film was used.

Comparative example 4
A decorative floor material was produced in the same manner as in Example 1, except that moisture-proof paper (polyethylene as a core layer and paper laminated on both sides. Moisture permeability: 10 g/m ^2.24 hours) was used as the moisture-proof film. .

Conventional example 1
A decorative floor material was produced in the same manner as in Example 1, except that 12 mm thick lauan plywood (dimensional change rate per 1% moisture content change was 0.016%) was used as the wood base material and no moisture-proof film was used. did.

Test example 1 (warping and bending in a 40°C atmosphere)
The floor decorative materials produced in Examples 1 to 4, Comparative Examples 1 to 4, and Conventional Example 1 were placed in a 40°C atmosphere (dry
The decorative material for flooring was left in an atmosphere (for 7 days), and the amount of warpage and amount of bending of the decorative floor material was measured.

A schematic diagram of the amount of warpage and amount of bending is shown in FIG. The amount of warpage and amount of bending was measured using a feeler gauge. If the amount of warpage is 20mm/1840mm (the amount of warpage relative to the horizontal length) or less, it is passed (suitable for practical use). In addition, the amount of towing bending is 0.3mm/1840mm (the amount of towing bending relative to the horizontal length) or less.
suitable for practical use). The results are shown in Table 1.

Test example 2 (warping and bending in an atmosphere of 40°C and 90% RH)
The decorative floor materials produced in Examples and Comparative Examples were left in an atmosphere of 40°C and 90% RH (7 days), and the amount of warpage and amount of bending of the decorative floor materials was measured in the same manner as Test Example 1. . The results are shown in Table 1.

As is clear from the results in Table 1 above, the decorative floor material of the present invention, which is provided with a moisture-proof film having a moisture permeability of 7 g/ ^m2.24 hours or less, has a dimensional stability that depends on the humidity of the wooden base material due to the presence of the moisture-proof film. Changes are effectively suppressed. As a result, warping and bending of the floor decorative material was prevented, and the result was closer to the test results of Conventional Example 1 (using lauan plywood).

Example 5
(1) Decorative floor sheet (0.16 mm thick, moisture permeability: 3 g/m ^2.24 hours) was made into a 12 mm thick sheet using Chuo Rika Kogyo adhesive (BA-10L/BA-11B, 9 g/square). It was attached to the front surface of particle board (PB) (wood base material). The dimensional change rate per 1% change in water content of the PB was 0.045%, and the average water content was 6.5% by weight.
(2) On the back side of PB, use Chuo Rika Kogyo adhesive (BA-10L/BA-11B, 9g/square) to apply a moisture-proof film (PET film + vapor deposition layer, moisture permeability: 3g/m ^2.24 hours) ) were pasted together. The laminate in this state is called a decorative board.
(3) The decorative board was cut with a gang saw to a size of 313 mm (length) x 1840 mm (width).
(4) Also, using a Tenona processing machine, tongue processing, end chamfering, and V-groove processing (V-groove processing width was 1.5 mm) were performed.
(5) Further, on the painting line, a paint was applied to the grooved part, the end chamfered part, and the V-groove part (paint: a paint containing a two-component curable urethane resin).

A decorative floor material was produced through the above steps. In addition, between each process, the decorative board was wrapped in a PP film (30 μm thick, moisture permeable 15 g) for moisture-proofing treatment.

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

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

Example 8
A decorative floor material was produced in the same manner as in Example 5, except that softwood plywood was used in which the moisture content in the central part of the wooden base material was 1.7% higher than in the peripheral part.

Comparative example 5
A decorative floor material was produced 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 decorative floor material was produced in the same manner as in Example 6, except that it was left for one week without being subjected to moisture-proofing treatment after Tenona processing.

Comparative example 7
A decorative floor material was produced in the same manner as in Example 5, except that a PB base material in which the moisture content in the central part of the wood was 2.5% higher than in the peripheral part was used.

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

Test Example 3 (Evaluation of bending and construction suitability after cutting decorative flooring material)
<Evaluation of the amount of bending after cutting>
The decorative floor materials (313 mm long x 1840 mm wide) produced in Examples 5 to 8 and Comparative Examples 5 to 8 were cut in half (150 mm long x 1840 mm wide) at the center.

The amount of horizontal bending of the cut flooring material was measured using a straight line ruler and a feeler gauge. Measurements were taken within 30 minutes after cutting. The amount of drag bending was indicated as + when each tongue side (male tongue, female tongue) was convex.

The amount of bending after cutting is allowed as long as it is within the range of -1.0mm/1840mm to +0.7mm/1840mm.
<Construction suitability evaluation>
The decorative floor materials (313 mm long x 1840 mm wide) produced in Examples 5 to 8 and Comparative Examples 5 to 8 were first constructed in their original size. Thereafter, a decorative floor material cut into approximately half (150 mm in length x 1840 mm in width) at the center was installed within 30 minutes after cutting, and its suitability for installation after cutting was evaluated. The evaluation criteria were as follows.

○: As before cutting, construction can be performed without any problems, and no gaps are observed at the seams.

△: It can be constructed with some effort, and no gaps are observed at the joints.

×: Construction is difficult, and a gap exceeding 0.3 mm is observed at the joint.

Test example 4 (floor heating system test)
The decorative floor materials (313 mm long x 1840 mm wide) produced 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 rooms (along walls or around pillars), but rather in the center of the room, excluding the corners. Therefore, in Test Example 4, a floor heating system test was conducted on a decorative floor material (313 mm long x 1840 mm wide).

Specifically, we used a test piece made of decorative flooring material as a test piece, and subjected it to the floor heating system test shown in Figure 4 (Finishing Materials/Substrate Material Edition "II. Durability Thermal Durability Test" 80℃ hot water x 1100 It was subjected to continuous hot water flow for hours (unified gas company standard method).

Regarding the test piece after the test,
(1) Pass if the gap displacement of the tongue-assembled part (fitting part) is 0.5 mm or less. (2) Pass if the step displacement of the tongue-assembled part (fitting part) is 0.5 mm or less. (3) Horizontal If the amount of warpage in the direction (1840 mm) (=width warpage) was less than 1 mm, evaluation was performed according to the criteria for passing. Those that passed all requirements were marked as ○, and those that did not meet at least one of the requirements were marked as ×.

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

As is clear from the results in Table 2 above, in particular, the average moisture content is 6 to 10% by weight, and the moisture content in the center is in the range of -1% to +2% compared to the moisture content in the periphery. By using a wood base material, bending after cutting can be effectively suppressed. Further, the decorative floor material of the present invention can be practically used as a floor material for floor heating because the moisture permeability of the moisture-proof film is 7 g/m ² ·24 hours or less.

That is, the present invention relates to the following floor decorative material .
1. A decorative floor material having a laminated structure comprising a decorative sheet, a wood base material, and a moisture-proof film from the front surface to the back surface ,
(1 ) The wood base material has a dimensional change per 1% change in moisture content of more than 0.02%, and an average moisture content of 6 to 10% by weight ,
(2) The decorative sheet has a pattern layer, a transparent resin layer containing a thermoplastic resin, and a surface protection layer in this order on a base sheet,
(3) The moisture permeability of the decorative sheet is 5 g/m ^2.24 hours or less,
(4) the moisture permeability of the moisture-proof film is equal to or lower than the moisture permeability of the decorative sheet;
(5) The floor decorative material is cut into a length of 150 mm x width of 1840 mm, and the amount of horizontal bending within 30 minutes after cutting is in the range of -1.0 mm to +0.7 mm.
A floor decorative material characterized by:
2. 2. The decorative floor material according to item 1, wherein the decorative sheet includes a synthetic resin layer having a thickness of 100 μm or more and 600 μm or less as the lowermost layer.

Claims (1)

A laminate A of the moisture-proof film and the wood base material used for a decorative floor material having a laminated structure comprising a decorative sheet, a wood base material, and a moisture-proof film from the front surface to the back surface,
(1) The moisture-proof film is
Moisture permeability is 1 g/m ^2.24 hours or less,
A laminate B comprising a primer layer made of a two-component curable urethane resin, an aluminum vapor deposited layer, and a surface coat layer containing a polyvinyl alcohol resin on one side of a thermoplastic resin film, in that order,
(2) The wood base material has a dimensional change per 1% change in moisture content of more than 0.02%, and an average moisture content of 6 to 10% by weight.
A laminate A of a moisture-proof film and a wood base material, characterized by: